BS 1377‑3:2018
BSI Standards Publication
Methods of test for soils for civil
engineering purposes –
Part 3: Chemical and electrochemical tests
BS 1377‑3:2018
BRITISH STANDARD
Publishing and copyright information
The BSI copyright notice displayed in this document indicates when the document was last issued.
© The British Standards Institution 2018
Published by BSI Standards Limited 2018
ISBN 978 0 580 96354 4
ICS 93.020
The following BSI references relate to the work on this document:
Committee reference B/526/3
Draft for comment 18/30351283 DC
Amendments/corrigenda issued since publication
Date
Text affected
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
Contents
Page
Foreword
ii
1
Scope
1
2
3
4
5
6
7
Normative references
Terms and definitions
Determination of the organic matter content
Determination of total organic carbon (TOC)
Determination of the mass loss on ignition
Determination of sulfur compounds
2
2
3
8
12
14
Table 1 — Example concentration of calibration ranges
Table 2 — Example anion concentrations in calibration standards
Table 3 — The concentration as a % of the upper limit of the apparatus of the different
calibration standards for ICP-AES
Table 4 — Example of five calibration standards for copper, magnesium and sulfur
Figure 1 — Constant-head device for use with ion-exchange column
Figure 2 — Ion-exchange column for sulfate determination
Figure 3 — Schematic diagram of the apparatus for total reduced sulfur determination
Figure 4 — Jones reductor assembly
Figure 5 — Apparatus for determination of acid-soluble mono-sulfide (MS)
44
8
Determination of the carbonate content
48
9
Determination of the chloride content
54
10
Determination of magnesium — water‑soluble magnesium in 2:1 extract
63
11
Determination of total dissolved solids
64
12
Determination of the pH value
66
13
Determination of electrical resistivity
68
14
Annex A
Figure 6 — Testing undisturbed cylindrical samples
Figure 7 — Design for open container for resistivity tests on saturated coarse soil
Figure 8a — Design for reduced size open container for resistivity tests on fine-grain cohesive
soil — Example of a small resistivity test cell for use with fine-grained soils
Figure 8b — Design for reduced size open container for resistivity tests on fine-grain cohesive
soil — Example of a reconstituted soil sample trimmed from a Proctor mould
Figure 9 — Circuit diagram for resistivity test using Wenner probes
Determination of the redox potential
(informative)
Bibliography
Determination of sulfur compounds
21
21
23
23
29
30
38
39
71
75
76
77
83
90
94
98
Summary of pages
This document comprises a front cover, and inside front cover, pages i to iv, pages 1 to 98, an inside back cover and
a back cover.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED I
BS 1377‑3:2018
BRITISH STANDARD
Foreword
Publishing information
This part of BS 1377 is published by BSI Standards Limited, under licence from The British Standards
Institution, and came into effect on 31 July 2018. It was prepared by Subcommitee B/526/3, Site
investigation and ground testing , under the authority of Technical Committee B/526, Geotechnics. A
list of organizations represented on these committees can be obtained on request to their secretary.
Supersession
This part of BS 1377 supersedes BS 1377‑3:1990, which is withdrawn.
Relationship with other publications
BS 1377‑3 is published in the following parts:
•
Part 1: General requirements and sample preparation ;
•
Part 2: Classification tests;
•
Part 3: Chemical and electrochemical tests;
•
Part 4: Compaction-related tests;
•
Part 5: Compressibility, permeability and durability tests;
•
Part 6: Consolidation and permeability tests in hydraulic cells and with pore pressure
measurement;
•
Part 7: Shear strength tests (total stress);
•
Part 8: Shear strength tests (effective stress) ;
•
Part 9: In-situ tests.
Information about this document
This part of BS 1377 is intended to be read in conjunction with BS 1377‑1.
In this part of BS 1377, the tests described in the 1990 edition have been retained. Additional tests
have been added to include the recommendations of BRE Special Digest 1 [SD1] (BRE 2005) [1] .
Also, analytical methods of chemical analysis have been included, i.e. total carbon analyzer, ion
chromatography and inductively coupled plasma atomic emission spectroscopy. The two point
resistivity method has been removed and additional four point tests included.
This is a full revision of the standard, and introduces the following principal changes:
•
determination of total organic carbon;
•
determination of total sulfur content;
•
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determination of water soluble magnesium.
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BRITISH STANDARD
BS 1377‑3:2018
Hazard warnings
WARNING. Persons using this British Standard are expected be familiar with normal laboratory practice.
This British Standard calls for the use of substances and/or procedures that can be injurious to health if
adequate precautions are not taken. It refers only to technical suitability and does not absolve the user from
legal obligations relating to health and safety at any stage. These include the use of fume cupboards or similar
apparatus when using acids and other toxic chemicals. This standard does not purport to address the safety
problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and
health practices and to ensure compliance with any national regulatory conditions.
It is expected that tests conducted in accordance with this British Standard will be carried out by suitably
trained and experienced staff.
WARNING. It is dangerous to add water to concentrated acid.
Use of this document
It has been assumed in the preparation of this part of BS 1377 that the execution of its provisions will
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Presentational conventions
The provisions of this standard are presented in roman (i.e. upright) type. Its methods are expressed
as a set of instructions, a description, or in sentences in which the principal auxiliary verb is “shall”.
Commentary, explanation and general informative material is presented in smaller italic type, and does
not constitute a normative element.
Contractual and legal considerations
This publication does not purport to include all the necessary provisions of a contract. Users are
responsible for its correct application.
Compliance with a British Standard cannot confer immunity from legal obligations.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED III
BS 1377‑3:2018
THIS PAGE DELIBERATELY LEFT BLANK
BRITISH STANDARD
BRITISH STANDARD
1
BS 1377‑3:2018
Scope
This part of BS 1377 describes test methods for determining the amount of chemical substances in
samples o f soil and extremely weak and very weak rocks, as defined by BS 5930, and groundwater.
NOTE 1 Chemical tests in this part of BS 1377 may be used on other rocks if required.
It also describes test methods for the determination of some electrochemical and resistivity
properties of solid samples.
NOTE 2 These tests provide data to assess the potential of the ground and solutes to damage construction
materials, including cementitious materials and metals in the ground. They can also be used in assessment of the
potential for volume change of the ground due to chemical reaction. Resistivity test results can also be used to assess
in-situ resistivity results.
This British Standard is not written for testing samples from contaminated land or for soil
quality assessment.
Procedures described in this part of BS 1377 are for the determination of the following:
a)
organic matter content in the material (Clause 4);
b)
total organic carbon (TOC) content in the material (Clause 5 );
c)
loss on ignition of the material (Clause 6 );
d)
sulfur compounds (Clause 7 ):
1)
water‑soluble sulfate content of the material by 2:1 extraction;
2)
sulfate content in groundwater;
3)
acid‑soluble sulfate content of the material;
4)
total sulfur content of the material;
5)
total sulfide content (total reduced sul fur) content o f the material;
6)
acid-soluble sulfide (monosulfides sul fur) content o f the material;
e)
carbonate content of the material (Clause 8 );
f)
chloride content (Clause 9 ):
1)
water‑soluble chloride content of the material;
2)
acid‑soluble chloride content of the material.
g)
water‑soluble magnesium content of the material (Clause 10 );
h)
total dissolved solids of the groundwater (Clause 11 );
i)
pH value (Clause 12 );
j)
electrical resistivity of the material (Clause 13 ); and
k)
redox potential of the material (Clause 14 ).
Brief guidance on the detrimental effects of sulfur compounds on engineering works and alternative
methods o f identi fying the specific minerals is given in Annex A.
NOTE 3 Good practice in chemical testing requires duplicate specimens to be tested. In each of the test methods
the measurement of only one value of the overall result is described. It is recognized that it is necessary in many
practical applications to make a number of tests in order to obtain a representative value and an indication of
the reliability of the results. Guidance on the number of measurements required and the treatment of the results
obtained are not provided in this standard.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 1
BS 1377‑3:2018
2
BRITISH STANDARD
Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes provisions of this document. For dated references, only the edition cited
applies. For undated references, the latest edition of the referenced document (including any
amendments) applies.
BS 89, Specification
for direct acting indicating electrical measuring instruments and their accessories
BS 1377‑1:2016, Methods of test for soils for civil engineering purposes — Part 1: General requirements
and sample preparation
BS 1881‑124:2015, Testing concrete — Part 124: Methods for analysis of hardened concrete
BS 5930, Code of practice for ground investigations
BS EN ISO 3696:1995, Water for analytical laboratory use — Specification
and test methods
BS EN ISO 17034, General requirements for the competence of reference material producers
BS EN ISO 17892‑1, Geotechnical investigation
and testing — Laboratory testing of soil —
Part 1: Determination of water content
BS EN ISO 22475‑1:2016, Geotechnical investigation and testing — Sampling methods and
groundwater measurements — Part 1: Technical principles for execution
3 Terms and definitions
For the purposes o f this part o f BS 1377, the terms and definitions given in BS 1377-1 and the
following apply.
3.1 titration
addition of a solution from a graduated burette to a known volume of a second solution, until the
chemical reaction between the two is completed
NOTE If the strength of one of the solutions is known, that of the other can be calculated from the volume of
liquid added.
3.2 indicator
substance which is capable of giving a clear visual indication of the completion of a chemical reaction
in a solution being titrated, usually by means of a change in colour
3.3 pH value
logarithm to base 10 of the reciprocal of the concentration of hydrogen ions in an aqueous solution
NOTE It provides a measure of the acidity or alkalinity of the solution on a scale reading from 0 to 14, on which 7
represents neutrality.
3.4 resistivity (of soil)
electrical resistance, in Ω (ohms) per unit length, o f a column o f soil o f unit area o f cross-section
NOTE
In this part of BS 1377, resistivity is expressed in Ωm (ohm metres).
3.5 redox potential (reduction/oxidation potential)
relative measure, expressed in millivolts, of the reducing or oxidising capacity of soil, usually
increasing with increasing oxygen content
2 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
3.6 calibration blank sample
extract solution used to make solutions
NOTE 1 For example, water or acid used for the preparation of extractions prior to analysis.
NOTE 2 The primary purpose of a blank is to trace sources of artificially introduced contamination and used to
facilitate correction of the final test sample result.
3.7 stock solution
solution with accurately known analyte concentration(s) prepared with an appropriate purity
NOTE
4
Stock solutions are reference materials within the meaning of PD ISO Guide 30.
Determination of the organic matter content
4.1 Principle
This procedure covers the determination of the percentage by dry mass of oxidisable organic matter
present in a soil.
NOTE
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The method, which uses dichromate oxidation, is known as Walkley and Black’s method.
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Methods for checking for the presence of these compounds, and procedures for their removal before
testing if they are present, are included.
The requirements of BS 1377‑1, where appropriate, shall apply to this test method.
4.2 Reagents
4.2.1
4.2.2
4.2.3
All reagents shall be of recognized analytical reagent quality.
NOTE Where accurately standardized solutions are required it might be more convenient to obtain them
already standardized in concentrated form and to dilute them as necessary in accordance with the manufacturer’s
instructions.
Potassium dichromate solution , [c(K2 Cr2 O 7) = 0.167 mol/l] . Dissolve 49.035 g of potassium dichromate
in distilled/de‑ionized water (BS 1377‑1:2016,
) to make 1 l of solution.
6.1
Ferrous sulfate solution . Dissolve approximately 140 g of ferrous sulfate in sulfuric acid solution
[c(H 2 SO 4) = 0.25 mol/l] to make 1 l of solution. Add 14 ml of concentrated sulfuric acid to distilled/de‑
ionized water (BS 1377‑1:2016,
) to make 1 l of sulfuric acid solution [c(H 2 SO 4) = 0.25 mol/l] .
Record the date the solution is made on the bottle. This solution is unstable in air. Keep it tightly
stoppered and standardize against the potassium dichromate solution at least once a week.
6.1
4.2.4
4.2.5
4.2.6
4.2.7
4.2.8
4.2.9
Sulfuric acid, concentrated. Density 1.84 g/ml.
Orthophosphoric acid, 85% (v/v) solution. Density 1.70 g/ml to 1.75 g/ml.
Indicator solution . Dissolve 0.25 g of sodium diphenylamine sulfonate in 100 ml of distilled/de‑
ionized water (BS 1377‑1:2016,
) water.
6.1
Hydrochloric acid, 25% (v/v) solution. Add 250 ml of concentrated hydrochloric acid (density
1.18 g/ml) to 500 ml of distilled/de‑ionized water (BS 1377‑1:2016,
), then make up to 1 l with
distilled/de‑ionized water (BS 1377‑1:2016,
).
6.1
6.1
Lead acetate paper. Filter paper that has been dipped in a 10% solution of lead acetate.
Sulfuric acid, [c(H2SO4) = approximately1 mol/l]. Add 53 ml of concentrated sulfuric acid to about
500 ml of distilled/de‑ionized water (BS 1377‑1:2016,
distilled/de‑ionized water (BS 1377‑1:2016,
6.1 ).
6.1 ) water, then make up to 1 l with
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 3
BS 1377‑3:2018
BRITISH STANDARD
4.3 Apparatus
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.3.6
4.3.7
4.3.8
4.3.9
Drying oven , capable of maintaining a temperature of (50 ±2.5) °C.
Balance, readable to 1 g.
Balance, readable to 0.001 g.
1 l volumetric flask.
Two 25 ml burettes, graduated to 0.1 ml.
10 ml pipette and a 1 ml pipette, each fitted with a rubber teat.
Two conical flasks of 500 ml capacity.
200 ml and 20 ml graduated measuring cylinders.
Desiccator, (a convenient size is about 200 mm to 250 mm in diameter) containing
anhydrous silica gel.
4.3.10
Glass weighing bottle, approximately 25 mm in diameter, 50 mm high and fitted with a ground
4.3.11
4.3.12
4.3.13
4.3.14
4.3.15
4.3.16
4.3.17
Test sieves, 2 mm and 0.425 mm aperture sizes, with receiver.
Sample dividers of multiple-slot type (riffle boxes), having widths of opening of 7 mm and 15 mm.
4.3.18
glass stopper.
Pestle and mortar, or a suitable mechanical crusher.
Wash bottle, preferably made of plastics, containing distilled/de‑ionized water (BS 1377‑1:2016, 6.1 ).
Glass boiling tube.
Filter funnel, of approximately 100 mm diameter.
Filter papers, of a diameter appropriate to the size of the funnel: medium grade (e.g. Whatman
No. 40 ® 1 ) and fine grade (e.g. Whatman No. 42 ® 1 ).
Blue litmus paper.
4.4 Preparation of test specimen
4.4.1
Each test specimen shall be prepared for analysis from the laboratory sample as given in
4.4.2
An initial sample shall be obtained as described in BS 1377‑1:2016,
4.4.3
4.4.4
4.4.5
4.4.6
1
4.4. 2 to 4.4.11 .
as specified in BS 1377-1:2016,
8.5 .
8.3 , and of the approximate size
The sample shall be dried in the oven to constant mass at (50 ±2.5) °C, and cooled to room
temperature in the desiccator.
The sample shall be weighed to the nearest 0.1% and the mass m 1 (in g) recorded.
The sample shall be sieved on a 2 mm test sieve (if appropriate, guarded by a test sieve of larger
aperture) and crush retained particles other than stones to pass the 2 mm sieve.
NOTE It is assumed that any material retained on the 2 mm test sieve will not contain organic matter. If this is
seen not to be true, the pieces of organic matter should be removed by hand, crushed to pass a 2 mm test sieve and
incorporated in the fraction passing the sieve.
The stones shall be rejected, ensuring that no fine material adheres to them, e.g. by brushing. Record
the mass of sample passing the 2 mm test sieve (in g) to the nearest 0.1% (m 2 ). Throughout these and
subsequent operations take care to ensure that there is no loss o f fines.
Whatman is a trademark of GE Healthcare. This information is given for the convenience of users of this document and does not constitute
an endorsement by the British Standards Institution of the named product. Equivalent products may be used if they can be shown to lead to
the same results.
4 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
4.4.7
4.4.8
4.4.9
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for a check test to determine whether chlorides are present, a specimen of about 50 g;
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NOTE Throughout this preparation and any subsequent operation mix the material available thoroughly before
any division and take care to avoid segregation during riffling.
Each specimen shall be placed in a glass weighing bottle and dried in the oven at a temperature of
(50 ±2.5) °C. The specimens shall be deemed to be dry when the differences in successive weighings,
carried out at intervals of 4 h, do not exceed 0.1% of the original mass of the sample.
4.4.11
The specimens shall be allowed to cool to room temperature in a desiccator containing dry self‑
indicating desiccant and each bottle and contents weighed to 0.001 g.
4.5 Procedure
4.5.1 Standardization of ferrous sulfate
4.5.1.1
10 ml of the potassium dichromate solution (
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k
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4.5.1.2
20 ml of concentrated sulfuric acid shall be added very carefully, the mixture swirled and allowed to
4.5.1.3
200 ml of distilled/de‑ionized water (BS 1377‑1:2016,
4.5.1.4
cool for some minutes.
mixture followed by 10 ml of phosphoric acid and 1 ml of the indicator, and shaken to mix thoroughly.
Ferrous sulfate solution shall be added from the second burette in 0.5 ml increments, and the
c
4.5.1.5
4.5.1.6
6.1 ) shall be added very carefully to the
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A further 0.5 ml of potassium dichromate solution shall be added, changing the colour back to blue.
Ferrous sulfate solution shall be added slowly drop by drop with continued swirling until the colour
of the solution changes from blue to green after the addition of a single drop.
4.5.1.7 The total volume of ferrous sulfate solution used shall be recorded, x, to the nearest 0.05 ml.
4.5.2 Qualitative check for sulfides
4.5.2.1
f
4.5.2.2 and 4.5.2.3 .
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i
n
A qualitative check might have been carried out in the tests for sulfide (see Clause 7, in particular 7.9)
The 5 g check sample (which need not be weighed) shall be placed in a boiling tube. 50 ml (approx.)
of hydrochloric acid (
h
1
4.5.2.3
h
y
d
0
r
o
%
g
s
e
o
l
NOTE
f
n
u
s
t
i
u
o
l
f
i
n
d
o
e
f
l
c
e
h
a
e
d
4.2.7 ) shall be added. This shall be brought to the boil and the presence of
c
k
e
a
c
d
e
f
o
t
a
r
t
e
.
b
y
T
h
h
i
s
o
l
d
w
i
i
l
n
l
g
i
t
u
n
r
t
h
n
b
e
l
a
v
a
c
p
k
i
o
f
u
h
r
a
y
d
p
r
o
i
e
g
c
e
e
n
o
s
f
u
l
f
i
f
i
l
t
e
d
e
r
i
p
s
a
p
p
e
r
e
r
s
e
t
h
n
a
t
t
h
a
s
b
e
e
n
d
i
p
p
e
d
i
n
a
.
This should be carried out in a fume cupboard.
f
f
4.5.3 before proceeding with the analysis for organic matter, otherwise a result that is too high will
I
t
h
e
p
r
e
s
e
n
c
e
o
s
u
l
f
i
d
e
s
i
s
i
n
d
i
c
a
t
e
d
i
t
s
h
a
l
l
b
e
r
e
m
o
v
e
d
r
o
m
t
h
e
t
e
s
t
s
p
e
c
i
m
e
n
a
s
d
e
s
c
r
i
b
e
d
i
n
be obtained.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 5
BS 1377‑3:2018
BRITISH STANDARD
4.5.2.4 f
f
4.5.3 .
4.5.3 Elimination of sulfides
4.5.3.1 About 50 g of the soil shall be weighed, after cooling as described in 4.4.10 and 4.4.11 , to 0.01 g and
I
t
h
p
4.5.3.2
a
c
e
p
d
r
i
4.5.3.5
4.5.3.6
s
n
u
T
l
h
f
i
e
d
c
e
o
o
n
e
a
n
5
c
e
0
o
0
s
m
u
l
c
l
f
i
o
d
n
i
e
c
s
a
i
l
s
f
l
n
a
o
s
t
i
n
d
i
c
a
t
e
d
,
o
m
i
t
t
h
e
p
r
o
c
e
d
u
r
e
g
i
v
e
n
i
n
k
.
c
c
t
e
u
n
r
s
t
s
,
a
o
f
s
d
t
h
e
e
t
e
c
r
o
m
n
i
i
c
n
a
l
e
d
f
l
b
a
s
y
k
t
e
s
s
h
t
i
a
l
n
l
g
b
w
e
i
f
i
t
h
l
t
e
l
r
e
e
a
d
d
a
o
c
n
e
a
t
a
t
e
m
e
p
d
i
a
u
p
e
m
r
.
g
r
a
d
e
f
i
l
t
e
r
p
a
p
e
r
,
t
a
k
i
n
g
c
a
r
e
t
o
r
e
t
a
i
n
all solid particles. This shall be washed several times with hot distilled/de‑ionized water (BS 1377‑
6.1 ) until the washings do not indicate acidity when tested with blue litmus.
1:2016,
4.5.3.4
e
Sulfuric acid solution [c(H 2 SO 4) = 1.0 mol/l] shall be added until no further evolution of hydrogen
s
4.5.3.3
l
e
T
h
e
s
o
i
l
r
e
t
a
i
n
e
d
o
n
t
h
e
f
i
l
t
e
r
p
a
p
e
r
s
h
a
l
l
b
e
d
r
i
e
d
t
o
c
o
n
s
t
a
n
t
m
a
s
s
a
t
a
t
e
m
p
e
r
a
t
u
r
e
o
f
(
5
0
±
2
.
5
)
°
C
and cooled in the desiccator.
T
h
e
s
o
i
l
s
h
a
l
l
b
e
c
a
r
e
f
u
l
l
y
r
e
m
o
v
e
f
d
r
o
m
t
h
e
f
i
l
t
e
r
p
a
p
e
r
a
n
d
i
t
s
m
a
s
s
d
e
t
e
r
m
i
n
e
d
t
o
0
.
0
1
g
.
4.4.9 , item a) and each test specimen shall be
The treated sample shall be subdivided as described in
4.4.10 and 4.4.11 .
4.5.4 Qualitative check for chlorides
4.5.4.1
f
f
9.2.3 .
4.5.4.2 If the presence of chlorides are indicated they shall be removed from the test specimen as described
in 4.5.5 before proceeding with the analysis for organic matter, otherwise a result that is too high will
dried and cooled as described in
T
h
e
p
r
e
s
e
n
c
e
o
c
h
l
o
r
i
d
e
s
i
n
t
h
e
s
o
i
l
s
h
a
l
l
b
e
v
e
r
i
f
i
e
d
b
y
o
l
l
o
w
i
n
g
t
h
e
p
r
o
c
e
d
u
r
e
d
e
s
c
r
i
b
e
d
i
n
be obtained.
NOTE 1 Alternatively, the effect of chlorides on the organic matter determination can be partly eliminated by
using concentrated sulfuric acid in which silver sulfate has been dissolved in place of the concentrated sulfuric acid
specified in
. If the ratio of carbon to chloride does not exceed unity, 25 g of silver sulfate per litre of sulfuric
acid will be sufficient to precipitate the chloride.
4. 2. 4
NOTE 2 If the presence of both sulfides and chlorides is indicated, the procedures described in
should both be carried out on the sample of soil used for determination of the organic content.
and
4. 5. 3
4. 5. 5
4.5.4.3 If the presence of chlorides is not indicated, omit the procedure given in 4.5.5 .
4.5.5 Elimination of chlorides
4.5.5.1 About 50 g of the soil shall be weighed, after cooling as described in 4.4.10 and 4.4.11 , to 0.01 g.
4.5.5.2
f
ionized water (BS 1377‑1:2016, 6.1 ) water.
4.5.5.3 Washing shall continue until no turbidity is observed when a drop of the wash water is tested with
T
h
e
s
o
i
l
s
h
a
l
l
b
e
p
l
a
c
e
d
o
n
a
m
e
d
i
u
m
-
g
r
a
d
e
f
i
l
t
e
r
p
a
p
e
r
i
n
a
u
n
n
e
l
a
n
d
w
a
s
h
e
d
w
i
t
h
d
i
s
t
i
l
l
e
d
/
d
e
-
silver nitrate solution.
4.5.5.4
4.5.5.5
4.5.5.6
T
h
e
s
o
i
l
r
e
t
a
i
n
e
d
o
n
t
h
e
f
i
l
t
e
r
p
a
p
e
r
s
h
a
l
l
b
e
d
r
i
e
d
t
o
c
o
n
s
t
a
n
t
m
a
s
s
a
t
a
t
e
m
p
e
r
a
t
u
r
e
o
f
(
5
0
±
2
.
5
)
°
C
and cooled in the desiccator.
A
l
l
t
h
e
s
o
i
l
s
h
a
l
l
b
e
c
a
r
e
f
u
l
l
y
r
e
m
o
v
e
d
f
r
o
m
t
h
e
f
i
l
t
e
r
p
a
The treated sample shall be subdivided as described in
dried and cooled as described in
4.4.10 and 4.4.11 .
p
e
r
a
n
d
i
t
s
m
a
s
s
d
e
t
e
r
m
i
n
e
d
t
o
0
.
0
1
g
.
4.4.9 , item a) and each test specimen shall be
4.5.6 Analysis for organic matter
4.5.6.1 Each weighing bottle containing soil, obtained as described in 4.4.4, shall be weighed to 0.001 g.
6 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
4.5.6.2
BS 1377‑3:2018
A small quantity, from 5.0 g to 0.2 g, depending on the organic content (see note), shall be transferred
t
o
a
d
r
y
5
0
0
m
l
c
o
n
i
c
a
l
f
l
a
s
k
,
t
h
e
w
e
i
g
h
i
n
g
b
o
t
t
l
e
r
e
w
e
i
g
h
e
d
a
n
d
t
h
e
m
a
s
s
o
f
s
o
i
l
r
e
m
o
v
e
d
(
m3)
calculated by difference.
4.5.6.3
NOTE The size of the sample for chemical analysis varies with the amount of organic matter present in the soil.
As much as 5 g might be required for soil low in organic matter, and as little as 0.2 g with a very peaty soil. After
a number of determinations have been made experience will indicate the most suitable size of sample to be taken.
Where this is not so, it is suggested that a series of samples of varying sizes should be tested. The determination
giving a total of 5 ml to 8 ml of potassium dichromate solution reduced should be taken as the one giving the
correct result.
10 ml of the potassium dichromate solution (
4.2.2
)
s
h
a
l
l
b
e
r
u
f
n
r
o
m
a
b
u
r
e
t
t
e
i
n
t
o
t
h
e
c
o
n
i
c
a
l
f
l
a
s
k
,
and 20 ml concentrated sulfuric acid added very carefully from a measuring cylinder. The mixture
shall be swirled for about 1 min, and then allowed to stand on a heat‑insulating surface for 30 min to
a
l
l
o
w
o
x
i
d
a
t
i
o
n
o
f
t
h
e
o
r
g
a
n
i
c
m
a
t
t
e
r
t
o
p
r
o
c
e
e
d
.
D
u
r
i
n
g
t
h
i
s
p
e
r
i
o
d
t
h
e
f
l
a
s
k
s
h
a
l
l
b
e
p
r
o
t
e
c
t
e
d
f
r
o
m
cold air and draughts.
4.5.6.4
200 ml of distilled/de‑ionized water (BS 1377‑1:2016,
6.1 ) shall be added very carefully to the
mixture, followed by 10 ml of orthophosphoric acid and1 ml of indicator, and the mixture thoroughly
shaken. If the indicator is absorbed by the soil a further 1 ml of the solution shall be added.
4.5.6.5
Ferrous sulfate solution shall be added from the second burette in 0.5 ml increments and the contents
o
4.5.6.6
4.5.6.7
4.5.6.8
f
t
h
e
f
l
a
s
k
s
w
i
r
l
e
d
u
n
t
i
l
t
h
e
c
o
l
o
u
r
o
f
t
h
e
s
o
l
u
t
i
o
n
c
h
a
n
g
e
s
f
r
o
m
b
l
u
e
t
o
g
r
e
e
n
.
A further 0.5 ml of potassium dichromate solution shall be added, changing the colour back to blue.
Ferrous sulfate solution shall be added slowly drop by drop with continued swirling until the colour
of the solution changes from blue to green after the addition of a single drop.
The total volume of ferrous sulfate solution used, y, shall be recorded to the nearest 0.05 ml.
4.6 Calculations
4.6.1
The total volume V (in ml) of potassium dichromate solution used to oxidise the organic matter in the
soil sample shall be calculated from the equation:
V = 10 . 5  1 − y 
x

(1)
where
is the total volume of ferrous sulfate solution used (see
x
is the total volume of ferrous sulfate solution used in the standardization test
(see
4.6.2
4.5.6.8 ) (in ml);
y
4.5.1 ) (in ml).
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the equation:
f
m2
r
a
c
t
i
o
n
f
i
n
e
r
t
h
a
n
2
m
m
=
m1
× 100
(2)
where
4.6.3
T
h
e
p
e
r
m1
is the initial dry mass of sample (in g);
m2
is the mass of the sample passing the 2 mm test sieve (in g).
c
e
n
t
a
g
e
o
f
o
r
g
a
n
i
c
m
a
t
t
e
r
p
r
e
s
e
n
t
i
n
t
h
e
f
r
a
c
t
i
o
n
o
f
t
h
e
s
o
i
l
s
p
e
c
i
m
e
n
f
i
n
e
r
t
h
a
n
2
m
m
f
o
r
e
a
c
h
determination shall be calculated from the equation (see note):
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 7
BS 1377‑3:2018
BRITISH STANDARD
percentage organic matter content =
0 . 67V
(3)
m3
where
is the mass of soil used in the test (in g).
m3
4.6.4
NOTE The method is based on wet oxidation of the organic content of the soil, and assumes that soil organic
matter contains an average of 58% (m/m) of carbon. The method employed oxidises approximately 77% of the
carbon in the organic matter, and these factors are included in the equation given. The factors will give correct
results only for soil containing natural organic matter.
If duplicate specimens have been tested, and if the individual results expressed as a percentage of
organic matter differ by no more than 2%, the mean result shall be calculated. If they differ by more
than 2%, the test shall be repeated starting with two new representative portions of soil.
4.7 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018, Clause 4
and shall contain the following information:
a)
the method of test used;
b)
the organic matter content present in the soil fraction passing a 2 mm test sieve to the nearest
0.1% of the original oven dry mass of soil;
c)
the percentage by dry mass of the original sample passing the 2 mm test sieve to the nearest 1%;
d
i
)
e)
f
s
u
l
f
i
d
e
s
o
r
c
h
l
o
r
i
d
e
s
h
a
v
e
b
e
e
n
i
d
e
n
t
i
f
i
e
d
i
n
the information required by BS 1377‑1:2016,
t
h
e
s
o
i
l
;
10.1 .
5 Determination of total organic carbon (TOC)
5.1 Principle
This procedure covers the determination of the percentage of total organic carbon present in a
sample by total carbon analyzer using the combustion method. Total organic carbon, which measures
just carbon, is different from organic matter, which includes all the elements (hydrogen, oxygen,
nitrogen, etc.) that are components of organic compounds. The inorganic carbon, as carbonate, is
removed prior to testing for total organic carbon.
NOTE An example of a routine method for the determination of TOC is described using a total carbon analyzer
controlled by a computer running appropriate software. The sample is washed with acid prior to analysis to remove
inorganic carbon so the result obtained from the instrument is only organic carbon. The sample is heated in a
high temperature combustion furnace (typically around 1 050 °C), through which a carrier gas, such as helium, is
constantly flowing. Once in the combustion furnace oxygen is introduced to combust the sample. The carrier gas
then conveys the combustion products via other furnace tubes containing materials to aid complete combustion
and remove halogens, then via a suitable desiccant to remove moisture. The remaining stream of gas passes
into a detector (e.g. infra-red) where carbon dioxide is determined as a function of time. Carbonate minerals are
ubiquitous in natural deposits and will affect the TOC determination. All metal carbonate minerals are unstable
and break down in the presence of hydrogen ions available in hydrochloric acid releasing the mineral carbon as
CO2. Most show reaction with cold dilute hydrochloric acid, but some such as dolomite, siderite, magnesite and
other less common forms are only very slowly soluble. The solubility increases significantly in hot hydrochloric acid.
Pre-treatment of soil and powdered rock samples with hot hydrochloric acid is essential to remove any carbonate
minerals and to ensure that the value of TOC determined accounts only for the total organic carbon present.
8 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
5.2 Reagents
5.2.1
5.2.2
5.2.3
5.2.4
5.2.5
5.2.6
All reagents shall be of recognized analytical reagent quality.
Concentrated hydrochloric acid (density 1.18 g/ml).
Hydrochloric acid, 10% (v/v) solution. Dilute 100 ml of concentrated hydrochloric acid (density
1.18 g/ml) to 1 ml with distilled/de‑ionized water (BS 1377‑1:2016,
).
6.1
High purity gaseous oxygen .
Combustion catalyst
,
a
s
s
p
e
c
i
f
i
e
d
b
y
t
h
e
i
n
s
t
r
u
m
e
n
t
m
a
n
u
f
a
c
t
u
r
e
r
.
Certified carbon standards, a range of carbon levels are required to provide a calibration over the
required range.
5.3 Apparatus
5.3.1
5.3.2
5.3.3
5.3.4
5.3.5
5.3.6
5.3.7
5.3.8
5.3.9
5.3.10
5.3.11
5.3.12
5.3.13
5.3.14
5.3.15
5.3.16
Drying oven , capable of maintaining a temperature of (50 ±2.5) °C.
Balance, readable to 0.01 g.
Balance, readable to 0.0001 g.
Conical flask.
Funnel.
Desiccator with dry self-indicating desiccant.
GF/C glass fibre filters.
Filterable crucibles and vacuum bath.
Beakers.
Pasteur pipette.
Hot plate.
Test sieves,
Sample dividers of multiple-slot type (riffle boxes), having widths of opening of 7 mm and 15 mm.
2
m
m
a
n
d
4
2
5
μ
m
a
p
e
r
t
u
r
e
s
i
z
e
s
,
w
i
t
h
r
e
c
e
i
v
e
r
.
Pestle and mortar, or a suitable mechanical crusher.
Carbon combustion analyzer and associated catalyst.
Appropriate pipework and regulator, as required, to convey the gasses to the carbon
combustion analyzer.
5.4 Preparation of test specimen
5.4.1
5.4.2
5.4.3
5.4.4
5.4.5
Each test specimen shall be prepared for analysis from the laboratory sample as given in
5.4. 2 to 5.4.10 .
An initial sample and of approximate size shall be obtained as described in BS 1377‑1:2016,
8.3 .
The sample shall be dried in the oven to constant mass at (50 ±2.5) °C, and cooled to room
temperature in the desiccator containing dry desiccant.
The sample shall be weighed to the nearest 0.1% and the mass recorded, m 1 (g).
The sample shall be sieved on a 2 mm test sieve (if appropriate, guarded by a test sieve of larger
aperture) and retained particles other than stones crushed to pass the 2 mm sieve.
NOTE It is assumed that any material retained on the 2 mm test sieve will not contain organic matter. If this is
seen not to be true, the pieces of organic matter should be removed by hand, crushed to pass a 2 mm test sieve and
incorporated in the fraction passing the sieve.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 9
BS 1377‑3:2018
5.4.6
T
5.4.8
5.4.9
5.4.10
e
s
t
o
n
e
s
s
h
a
l
l
b
e
r
e
j
e
c
t
e
d
,
e
n
s
u
r
i
n
g
t
h
a
t
n
o
f
i
n
e
m
a
t
e
r
i
a
l
a
d
h
e
r
e
s
t
o
t
h
e
m
,
e
.
g
.
b
y
b
r
u
s
h
i
n
g
.
The mass of sample passing the 2 mm test sieve shall be recorded (in g) to the nearest 0.1%
(m 2 ). Throughout these and subsequent operations care shall be taken to ensure that there is no
l
5.4.7
h
BRITISH STANDARD
o
T
s
h
s
o
e
f
m
f
i
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r
s
i
.
a
l
p
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i
n
g
t
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2
m
m
s
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a
l
l
b
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d
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v
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d
b
y
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r
i
f
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n
g
t
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r
o
u
g
h
t
h
e
1
5
m
m
d
i
v
i
d
e
to produce a sample weighing approximately 100 g.
T
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i
s
s
a
m
p
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a
l
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p
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d
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a
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e
s
t
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e
4
2
5
μ
m
t
e
s
t
s
i
e
v
e
.
Each specimen shall be placed in a glass weighing bottle and dried in the oven at a temperature of
(50 ±2.5) °C. The specimens shall be deemed to be dry when the differences in successive weighings,
carried out at intervals of 4 h, do not exceed 0.1% of the original mass of the sample.
The specimen shall be cooled to room temperature in the desiccator and each bottle and contents
weighed to 0.001 g.
5.5 Procedure
5.5.1 Determination of test sample mass
T
h
T
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e
g
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c
,
m 3, recorded to the nearest 0.001
m 4, to the
u
nearest 0.001 g.
v
e
t
t
e
a
n
d
r
e
w
e
i
g
h
e
d
g.
,
NOTE 1 The mass of the sample tested depends on the organic carbon content, apparatus used and the
manufacturer's recommendations for that apparatus. Samples with high organic content, such as peaty material,
require lower test mass than for instance material containing high carbonate and low organic carbon.
NOTE 2 The size of the sample for chemical analysis may be reduced when there is a large amount of organic
matter present in the soil. After a number of determinations have been made experience will indicate the most
suitable size of sample to be taken.
5.5.2 Removal of inorganic carbon
5.5.2.1 The carbonate content shall be removed from the sample as described in 5.5.2.2 to 5.5.2.10 .
5.5.2.2
f
T
o
5.5.2.3
h
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e
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i
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a
c
o
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i
c
a
l
f
l
a
s
k
,
.
Cold 10% hydrochloric acid shall be added drop by drop to the sample until each sample is wet, if
u
s
i
n
g
f
i
l
NOTE
t
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r
a
b
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r
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b
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e
s
t
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n
o
n
t
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e
v
a
c
u
u
m
.
This process should be carried out in a fume cupboard, beneath an extractor hood or similar equipment.
5.5.2.4
The addition of acid might cause the samples to effervesce, if so, the 10% hydrochloric acid shall be
added until no further reaction can be seen.
5.5.2.5
Hot [(90 ±5) °C] 10% hydrochloric acid shall then be added drop by drop until no reaction
can be seen.
5.5.2.6
Washing with hot concentrated hydrochloric acid (5.2.2 ) shall be repeated. Each aliquot shall be
a
5.5.2.7
5.5.2.8
5.5.2.9
l
l
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t
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e
x
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d
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t
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o
n
i
s
m
a
d
e
.
The sample shall be washed with six washings of a Pasteur pipette full (approximately 1 ml) of hot
[(90 ±5) °C] distilled/de‑ionized water (BS 1377‑1, 6.1 ). The water shall be allowed to drain through
between each addition.
O
n
c
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t
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e
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i
q
u
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a
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,
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s
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a
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p
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i
s
l
o
s
t
a
n
d
p
l
a
c
e
d
in a crucible.
The crucible shall be placed into the oven at (105 ±5) °C for at least 2 h or until the sample is dry.
10 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
r
BRITISH STANDARD
5.5.2.10
BS 1377‑3:2018
The crucible shall be removed from the oven and placed in a desiccator with dry self‑indicating
desiccant to cool until ready for analysis.
5.5.3 Analysis for total organic carbon
A representative sub sample of suitable mass as recommended by the apparatus manufacturers, shall
be placed into a ceramic crucible, and then placed on the auto‑sampler of the analyzer. The crucible
is mechanically lowered into the combustion furnace and the test shall proceed as in the apparatus
manufacturer’s recommendations.
5.5.4 Calibration
5.5.4.1
f
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t
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o
f
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l
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e
s
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d
a
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r
each service.
5.5.4.2
5.5.4.3
5.5.4.4
T
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e
c
o
m
b
u
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t
i
o
n
a
n
a
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y
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r
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c
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b
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n
standards with different organic carbon contents following the manufacturer’s instructions.
The analysis of samples and check standards shall be as per manufacturer’s instructions.
Procedural blanks shall be run in duplicate. The instrumental software should automatically register
t
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a
t
t
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e
c
a
r
b
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s
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n
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k
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r
a
n
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e
.
I
f
b
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t
h
o
f
t
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e
s
e
duplicates values exceed this value, remedial action shall be taken to identify and correct it.
NOTE 1 This method does not measure soluble organic compounds as they are removed during the acidification
and washing procedure.
NOTE 2 Any chloride or water not removed by the instrument can corrode analyzer components and/or interfere
with the determination of carbon dioxide.
5.6 Calculations
5.6.1
The weight of sample prior to acid washing, m 5 (which is equal to m 4 – m 3 ) shall be input into the
apparatus computer data for that sample as required and the results from the instrument are as
% carbon. Because the acid washing has removed inorganic carbon this will equate to the % total
organic carbon present in the dry soil.
5.6.2
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the equation:
f
r
a
c
t
i
o
n
f
i
n
e
r
t
h
a
n
2
m
m
=
m 2 × 100
m1
(4)
where
m1
m2
is the initial dry mass of sample (in g);
is the mass of the sample passing the 2 mm test sieve (in g).
5.7 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018, Clause 5
and shall contain the following information:
a)
the method of test used, BS 1377‑3, test 5;
b)
the apparatus used;
c)
the total organic carbon present in the soil fraction passing a 2 mm test sieve to the nearest 0.1%
of the original oven dry mass of soil;
d)
the percentage by dry mass of the original sample passing the 2 mm test sieve to the
nearest 1%; and
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 11
BS 1377‑3:2018
e)
6
BRITISH STANDARD
the information required by BS 1377‑1:2016,
10.1 .
Determination of the mass loss on ignition
6.1 Principle
This clause describes the procedure for determining the proportion by mass that is lost from a soil by
ignition at a specified temperature.
The mass loss only relates to the organic content of peat, organic sand and materials that do not
contain minerals that decompose or dehydrate at the test temperature such as clay minerals, calcium
carbonate and gypsum. Such minerals might be responsible for the major proportion of the mass loss
on ignition.
The requirements of BS 1377‑1, where appropriate, shall apply to this test method.
6.2 Apparatus
6.2.1
6.2.2
6.2.3
6.2.4
6.2.5
6.2.6
6.2.7
6.2.8
6.2.9
Drying oven, capable of maintaining a temperature of (50 ±2.5) °C.
Balance, readable to 1 g.
Balance, readable to 0.001 g.
Desiccator, containing anhydrous silica gel.
Test sieves, 2 mm and 425 μm aperture sizes, with receiver.
Pestle and mortar, or a suitable mechanical crusher.
Sample dividers of the multiple-slot type (riffle boxes), having widths of opening of 7 mm and 15 mm.
Crucible or similar container, of about 30 ml capacity.
Electric muffle furnace, capable of maintaining a temperature of (440 ±25) °C.
6.3 Procedure
6.3.1 Preparation of crucible
6.3.1.1
6.3.1.2
6.3.1.3
Before starting each series of tests, a test shall be carried out on the empty crucible or container as
described in
6.3.1.2 to 6.3.1.4.
The crucible shall be placed in the mu ffle furnace, heated to (440 ±25) °C, and maintained for 1 h.
The crucible shall be removed from the furnace and allowed to cool to room temperature in
the desiccator.
6.3.1.4 The crucible shall be weighed to the nearest 0.001 g (m ).
6.3.2 Preparation of test specimen
6.3.2.1 Each test specimen shall be prepared for analysis from the laboratory sample as described in 6.3.2.2
to 6.3.2.11 .
6.3.2.2 The initial sample shall be obtained as described in BS 1377‑1:2016, 8.3 , and of the approximate
c
mass as specified in BS 1377-1:2016, Table 5 .
6.3.2.3
6.3.2.4
6.3.2.5
The sample shall be dried in the oven at (50 ±2.5) °C, and cooled to room temperature in
the desiccator.
The sample shall be weighed to the nearest 0.1 % and the mass recorded, m 1 (in g).
The sample shall be sieved on a 2 mm test sieve (if appropriate, guarded by a test sieve of larger
aperture), and retained particles other than stones shall be crushed to pass the 2 mm test sieve.
12 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
6.3.2.6
BS 1377‑3:2018
Fine material adhering to stones shall be brushed off into the sieve. The stones shall then be
rejected. The mass of the sample passing the 2 mm test sieve shall be recorded to the nearest 0.1%
(m 2 ). Throughout these and subsequent operations care shall be taken to ensure that there is no
l
6.3.2.7
6.3.2.8
6.3.2.9
o
T
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f
m
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r
s
i
.
a
l
p
a
s
s
i
n
g
t
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e
2
m
m
s
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e
v
e
s
h
a
l
l
b
e
d
i
v
i
d
e
d
b
y
s
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c
c
e
s
s
i
v
e
r
i
f
f
l
i
n
g
t
h
r
o
u
g
h
t
h
e
1
5
m
m
d
i
v
i
d
e
r
to produce a sample weighing at least 10 g.
T
h
i
T
s
h
e
s
s
a
a
m
m
p
p
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e
e
s
s
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a
a
l
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d
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e
s
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t
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e
7
e
4
m
2
5
m
μ
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h
weighing approximately 5 g. Throughout this and any subsequent operation the material shall be
m
6.3.2.10
s
i
x
e
d
t
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o
r
o
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y
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r
i
f
f
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i
n
g
.
Each specimen shall be placed in a prepared crucible and dried in the oven at a temperature of
(50 ±2.5) °C. The specimens shall be deemed to be dry when the differences in successive weighings,
carried out at intervals of 4 h, do not exceed 0.1% of the original mass of the sample.
6.3.2.11
The specimen shall be allowed to cool to room temperature in the desiccator and each crucible
weighed to 0.001 g (m 3 ).
6.3.3 Ignition of soil
6.3.3.1 Ignite each test specimen as described in 6.3.3.2 to 6.3.3.4.
6.3.3.2
f
T
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r
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b
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o
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o
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e
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h
t
,
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,
a
n
d
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e
n
heated to (440 ±25) °C, and this temperature shall be maintained for not less than 3 h.
6.3.3.3
6.3.3.4
NOTE
The period required for ignition will vary with the type of soil and size of sample.
The crucible and contents shall be removed from the furnace and allowed to cool to room
temperature in the desiccator.
The crucible and contents shall then be weighed to the nearest 0.001 g (m 4).
6.4 Calculations
6.4.1
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the equation:
f
r
a
c
t
i
o
n
f
i
n
e
r
t
h
a
n
2
m
m
=
m 2 × 100
m1
(5)
where
6.4.2
m
m
1
is the initial dry mass of sample (in g);
2
is the mass of the sample passing the 2 mm test sieve (in g).
The mass loss on ignition, LOI, as a percentage of the dry mass of soil passing a 2 mm test sieve shall
be calculated from the equation:
LOI =
m 3 − m 4 × 100 %
m3 − m c
(6)
where
m
m
m
3
is the mass of the crucible and oven‑dry soil specimen (in g);
4
is the mass of the crucible and specimen after ignition (in g);
c
is the mass of the crucible (in g).
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 13
BS 1377‑3:2018
BRITISH STANDARD
6.5 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018, Clause 6
and shall contain the following information:
a)
the method of test used;
b)
the mass loss on ignition as a percentage of the soil fraction passing the 2 mm test sieve, to two
significant figures;
c)
the percentage by dry mass of the original sample passing the 2 mm test sieve, to the
nearest 1%; and
d)
the information required by BS 1377‑1:2016, 10.1 .
7 Determination of sulfur compounds
7.1 General
7.1.1 Principle
This clause describes procedures for determining sulfur species in soils and extremely weak and very
weak rocks, as defined in BS 5930, and sul fate in groundwater.
NOTE The tests for sulfur species in this part of BS 1377 may be used on other rocks if required. Sulfur species
include sulfate minerals such as gypsum (CaSO4.2H2O), anhydrite (CaSO4), barite (BaSO4), jarosite [KFe3(OH) 6(SO4) 2]
and sulfide minerals, such as pyrrhotite (Fe(1-x)S), pyrite (FeS2), marcasite (FeS2), together with complex organic
sulfur compounds. They are commonly found in both natural ground and in anthropogenic materials. The oxidation
of sulfide minerals produces sulfuric acid, which reacts with calcium carbonate (CaCO3) to produce gypsum. This
reaction occurs as a result of natural weathering and also where natural deposits are disturbed by construction
work (see Czerewko et al. 2016) [7]. Where there is insufficient calcium carbonate or other mineral to buffer the
reaction, acid groundwater might be produced. Further information and references are given in Annex A.
7.1.2 Types of test
Procedures are described for the determination of the following:
a)
b)
c)
the water-soluble sul fate content o f a specimen, for which a water extract is first
prepared (see 7.3 );
the dissolved sulfate in groundwater (see 7.8 );
the acid-soluble sul fate content o f a specimen for which an acid extract is first
prepared (see 7.9 );
d)
the total sulfur content of a specimen (7.10 );
e)
the total reduced sul fur (sulfide) content o f a specimen for which an extract is prepared (
f)
the acid-soluble sulfide content o f a specimen for which an acid extract is prepared (
NOTE
7.11) ;
7.11 ).
Guidance is given in BS EN 1744-1 on testing for sulfur compounds in aggregates.
7.2 Sampling, sample storage and sample preparation
7.2.1 General
Samples shall be taken in accordance with the recommendations in BS 1377‑1:2016, 8.3 with
modifications herein to preserve the original chemistry o f the materials (see BRE [2005] [1] , TRL 447
[2005] [2] ).
14 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
The sampling, storage, sub‑sampling and testing operations shall be carefully planned at the outset of
investigations so changes in the type and amounts of sulfur compounds in the ground are preserved
in the samples.
NOTE The use of water or drilling fluid during recovery that might come into contact with the sample should be
avoided or, if necessary, kept to a minimum for sample recovery and noted for the samples, or material taken from
within undisturbed samples or core that has not been exposed to drilling fluids. Guidance for appropriate sampling,
handling and labelling procedures are given in BS EN 1997-2, BS EN ISO 22475-1 and BS 5930. The colour of the
sample should be recorded on receipt as described in BS 5930.
Sampling tools shall be clean. Samples shall be taken as soon as practicable with the delay between
excavation and sampling kept to a minimum. The time of sampling shall be noted and used to limit the
time until tested for the sulfur species. Care shall be taken to avoid samples becoming contaminated
with overlying or surface materials. I f water is present, this shall also be sampled, as specified in
BS EN ISO 22475‑1. Notes shall be made concerning the nature of the samples, for example, whether
a bulk representative sample or a sample o f a specific feature, such as a particular horizon or zone,
has been taken. The dates and environmental conditions to which samples are subjected during
transportation and storage shall be recorded.
7.2.2 Storage
Samples shall be packed and retained in clean, airtight, individual containers with no or minimal
airspace as soon after sampling as is practicable. They shall be stored at between 0 °C and 4 °C for
no longer than 14 days after sampling before testing. If storage is anticipated for longer, the samples
shall be dried in a ventilated oven at between 40 °C and 60 °C until a constant mass is reached and
placed in airtight containers, or vacuum pouches or under a vacuum and stored under refrigerated
conditions (at between 0 °C and 4 °C).
The water loss of material during the drying process shall be recorded and presented with the
test results.
7.2.3 Sample preparation
7.2.3.1 Apparatus
7.2.3.1.1 Drying oven, capable of being maintained at a temperature of between 40 °C and 60 °C.
7.2.3.1.2
Balance, readable to 1 g.
7.2.3.1.3
Balance, readable to 0.001 g.
7.2.3.1.4
Sieves, 5 mm, 2 mm and 212 μm aperture sizes, with receiver.
7.2.3.1.5
Pestle and mortar, agate or ceramic.
7.2.3.1.6
Mechanical crusher.
7.2.3.1.7
Binocular microscope, o f magnification x 35 or greater.
7.2.3.1.8
Sample dividers of multiple-slot type (riffle boxes), having widths of opening of 7 mm and 15 mm.
7.2.3.1.9
Desiccator, containing anhydrous silica gel.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 15
BS 1377‑3:2018
7.2.3.1.10
7.2.3.1.11
BRITISH STANDARD
Glass weighing-bottle,
approximately 50 mm in diameter, 25 mm high and fitted with a ground-
glass stopper.
Tungsten carbide disc shatter mill, or equivalent.
NOTE
A steel hammer and plate may also be used.
7.2.3.2 Drying of samples
Samples shall be dried in a clean, suitable container at a temperature of between 40 °C and 60 °C
in a fan‑assisted or conventional ventilated oven to a constant weight. The specimens shall be
deemed to be dry when the differences in successive weighings, carried out at intervals of 4 h, do not
exceed 0.1% of the original mass of the sample. The samples shall then be allowed to cool to room
temperature in the desiccator. The dried sample shall be weighed to the nearest 0.1 g and the mass
recorded as m 1 in g.
7.2.3.3 Mechanical processing
7.2.3.3.1 Coarse-grained material
The dried coarse‑grained material shall be dry sieved using 5 mm and 2 mm sieves. Material retained
on the sieves shall be examined using a binocular microscope o f magnification × 35 or similar. I f the
>5 mm retained fraction consists of inert material such as quartz then the material shall be brushed
clean of any adhering particles, which shall be added to the <2 mm fraction, and the inert fragments
shall be retained for weighing. If the material consists of weakly cemented grains, they shall be
broken down by gentle pounding using a clean agate or ceramic pestle and mortar and re‑sieved. If
the retained material consists of dried clay, silt, mudstone or siltstone or any material considered
to be a potential host for sul fur minerals as identified by a suitably experienced person, it shall be
crushed and added to the fraction passing the 2 mm sieve, which is retained for testing.
The <2 mm fraction shall be weighed to the nearest 0.1 g and the mass m 2 shall be recorded in g.
7.2.3.3.2 Fine-grained material
The dried fine-grained material shall be broken down using a clean ceramic mortar and rubber
pestle. Any gravel size (>2 mm) material shall be removed for examination under a binocular
microscope. Any fragments of inert material shall be brushed clean of any adhering particles, which
shall be added to the disaggregated material and retained for weighing. If the retained material
consists of clay, mudstone, silt, siltstone or any material considered to be a potential host for sulfur
minerals, as identified by a suitably experienced person, it shall be added to the disaggregated
fraction which is retained for testing.
The <2 mm fraction shall be weighed to the nearest 0.1 g and the mass m 2 shall be recorded in g.
7.2.3.4 Extremely weak and very weak rock
After drying, samples shall be brushed clean of any loose particles and then broken down into
fragments
o f less than 10 mm using a clean industrial fly press; alternatively, a hammer and steel
plate or a steel pestle and mortar or other similar equipment may be used. The material is retained
for testing. Care shall be taken when using mechanical crushing devices that samples do not become
heated above 60
NOTE
°C by the pounding action.
For intact rock samples the tests are carried out on m 1 . The fraction finer than 2 mm, m 2, is 0.
7.2.3.5 Subdividing
The material retained for testing shall be mixed thoroughly and subdivided by cone and quartering or
ri ffling until a representative sub-sample o f between 200 g and 300 g is obtained.
16 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
7.2.3.6 Particle size reduction
The particle size reduction shall be accomplished using a clean tungsten carbide disc shatter mill,
or an equivalent type of mill. The samples shall be subjected to successive episodes of between 10
and 15 seconds of milling. Longer periods shall be avoided as they might cause alteration to sulfur
s
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.
7.2.3.7 Storage of processed material
When samples are to be stored before testing, the powdered samples shall be oven dried at a
temperature of between 40 °C and 60 °C for about 24 hours. The samples shall then be allowed to
cool to room temperature in a desiccator with dry desiccant and stored as described in 7.2.2 .
7.3 Determination of water-soluble sulfate in soil (WS)
7.3.1 Principle
The method measures the water‑soluble sulfate of solid samples. The prepared dry sample is mixed
w
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is tested for sulfate ions. The results obtained give the sulfate content at the time of sampling only.
NOTE 1 The test methods in 7.4, 7.5, 7.6 and 7.7 may also be used to determine the sulfate content of samples of
groundwater and surface water provided they have been filtered using the method given in 7.3.3.5 and 7.3.3.6
as required.
NOTE 2 Water-soluble sulfate is an index value that is used for the assessment of the potentially aggressive sulfate
that might be readily leached from soil and rocks. The most common sulfate, hydrated calcium sulfate (CaSO4.2H2O,
gypsum) has a relatively low solubility of about 1 500 mg/l SO4 at room temperature. However, other sulfate
minerals, particularly those containing magnesium or sodium, have much higher solubility and, hence, pose greater
risk to concrete, steel and construction materials. Therefore, it might be necessary to test the water extract for
cations; such as magnesium (Clause 10). The total amount of potentially reactive sulfate is given by the acid-soluble
sulfate test in 7.9.
7.3.2 Preparation of water: soil extract
7.3.2.1 General
The requirements of BS 1377‑1:2016, where appropriate, shall apply to this test method.
7.3.2.2 Reagents
7.3.2.2.1
Nitric acid, analytical grade concentrated nitric acid, 1.42 g/ml (solution = 70%) for use if water
7.3.2.2.2
Hydrochloric acid, analytical grade concentrated hydrochloric acid, 1.19 g/ml (solution = 40%). Used if
samples need to be stored for ICP‑AES or gravimetric chemical determination methods only.
samples are to be stored for ICP‑AES or gravimetric chemical determination methods only.
7.3.2.3 Apparatus
7.3.2.3.1
For test sample preparation prior to water:soil extraction see 7.2.3 .
7.3.2.3.2
Extraction bottle, a 250 ml capacity clean and dry, rigid plastic such as high‑density polyethylene
(HDPE) container with a water tight screw cap. Glass containers should not be used as they are
susceptible to damage from the soil particles during the extraction.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 17
BS 1377‑3:2018
BRITISH STANDARD
7.3.2.3.3
Mechanical shaker, a rotary tumbler or mechanical shaker capable of keeping 50 g of soil in suspension
7.3.2.3.4
Sample bottles, 30 ml to 50 ml capacity sterile polystyrene or polypropylene sample bottles with
7.3.2.3.5
Vacuum filtration unit with filter funnel, flask and filter paper (e.g. Whatman No. 542® 2 ).
7.3.2.3.6
Syringe filter
7.3.2.3.7
pH meter, calibrated, electronic pH meter.
7.3.2.3.8
Laboratory glassware, including 75 mm diameter watch glass and 50 ml and 25 ml pipettes.
in 100 ml of water.
leak‑proof caps.
,
0
.
4
5
μ
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.
7.3.3 Procedure
7.3.3.1 A 30 g to 50 g representative portion of the oven‑dried powdered sample from 7.2.3.6 shall be
7.3.3.2
weighed and put into the 250 ml capacity extraction bottle to an accuracy of 0.001 g and record as m 3.
Between 60 ml and 100 ml of distilled/de‑ionized water (BS 1377‑1:2016, 6.1 ) water shall be added,
recording the amount to make a 2:1 water to sample mixture (by mass) as V1 assuming that 1 ml has a
mass of 1 g.
7.3.3.3
The extraction bottle shall be tightly stoppered. A blank of around 10 ml of the distilled/de‑
ionized water (BS 1377‑1:2016, 6.1 ) water for each batch of extractions shall be retained for
chemical analysis.
7.3.3.4
The extraction vessel shall be placed in a mechanical shaker or mechanical rotator and agitated for at
least 16 h (overnight).
7.3.3.5
T
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7.3.3.6
7.3.3.7
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without the addition of water.
An aliquot of 50 ml (approx.) shall be retained for chemical determination and the measurement of
pH (see Clause 12 ), however, this measurement is made on a 2:1 extract and shall not to be confused
with the pH determination in Clause 12 , which is carried out on a 2.5:1 extract.
7.3.4 Methods of chemical analysis
7.3.4.1 The chemical tests used for the determination of water‑soluble sulfate are ion chromatography (IC),
inductively coupled plasma atomic emission spectroscopy (ICP‑AES), gravimetric or ion exchange
column methods.
7.3.4.2
7.3.4.3
2
If ion chromatography (IC) method (see 7.4 ) is used the samples shall not have any chemicals added
to preserve them. Dilution might be necessary to bring the sulfate content within the validated
range of the IC apparatus or within acceptable levels for the total anion content of the sample and
correction made for the dilution. For the procedure see 7.4.
If ICP‑AES or similar apparatus (see 7.5 ) is to be used and the water sample is to be stored then
it shall be preserved using 1% v/v nitric acid and 0.5% v/v hydrochloric acid with respect to
concentrated analytical grade reagents. An aliquot of the sample shall be taken for analysis and
Whatman is a trademark of GE Healthcare. This information is given for the convenience of users of this document and does not constitute
an endorsement by the British Standards Institution of the named product. Equivalent products may be used if they can be shown to lead to
the same results.
18 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
diluted, if necessary, with a 1% nitric acid and 0.5% hydrochloric acid blank, which forms the blank
used as part of the analytical run.
7.3.4.4
If the gravimetric method of analysis (see
water (BS 1377‑1:2016,
7.3.4.5
7.6
)
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transferred into a clean, dry 500 ml conical beaker and diluted to 300 ml with distilled/de‑ionized
6.1 ).
If the ion‑exchange column method of analysis (see
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7.7 ) is to be used, no additional water shall be
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7.3.5 Test report
The test report shall state that the test was carried out in accordance BS 1377‑3,
chemical test method and shall contain the following information:
t
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1
0
0
m
l
o
f
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e
.
7.3 and relevant
a)
the method of test used;
b)
the water‑soluble sulfate content to the nearest 10 mg/l as SO 4;
c)
the percentage by dry mass of the original sample passing a 2 mm test sieve, to the nearest 1%;
d)
the pH of the water extract to the nearest 0.1 pH unit; and
e)
the information required by BS 1377‑1:2016,
10.1 .
7.4 Ion Chromatography (IC) method for analysis of water extract or groundwater sulfate
7.4.1 General
Ion chromatography is used in this standard to analyze 2:1 water soluble sulfate and chloride ions
and groundwater sulfate. Laboratories shall follow BS EN ISO 17034.
7.4.2 Principle
Anions are determined by injecting a known volume of sample as a solution, into a mobile eluent
phase, which passes through a separating column containing a stationary phase (absorbent). This
partitions the anions between the stationary absorbent, which differentially retards the ion according
to charge and charge mass, and the moving eluent/sample mixture. A detector analyzes the output at
the end of the column and produces a time vs detected anion output. The result is usually given by the
equipment computer, alternatively, it is on a printed chromatogram. The values, which are for sulfate
and chloride ions are in mg/l.
7.4.3 Reagents
7.4.3.1 Only reagents of analytical grade shall be used. Weigh the reagents with an accuracy of ±1% of the
normal mass.
7.4.3.2
7.4.3.3
7.4.3.4
7.4.3.5
Water, BS EN ISO 3696:1995, grade 1.
Sodium chloride.
Sodium sulfate.
Chemicals for eluents.
NOTE 1 The choice of eluent depends on the choice of column and detector, seek advice from the column supplier.
NOTE 2 Stock solutions may be made up by the laboratory (see BS EN ISO 17034) or bought from suppliers to
laboratories requirements. BS EN ISO/IEC 17025 requires tractability for all reference standards used.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 19
BS 1377‑3:2018
BRITISH STANDARD
7.4.4 Apparatus
7.4.4.1 Ion chromatography system , typically consisting of a gradational pump, an electrochemical detector,
a guard column, an absorbance detector, an autosampler and a thermal compartment. The system
is controlled and data capture is by a dedicated computer installed with proprietary software. The
s
7.4.4.2
7.4.4.3
7.4.4.4
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.
Eluent reservoir.
Refrigerator for storing solutions.
Equipment for making and storing chemical solutions.
NOTE The concentration of the analyte should be limited to that recommended by the manufacturer and by the
laboratory as in Table 1 . High concentrations of anions might not be accurately measured and shorten the life of the
separating column.
7.4.4.5
The autosampler door shall not be opened during sample injection sequence.
WARNING. There are various hazards associated with ion chromatographs such as operation at high
pressure and ultra‑violet radiation from the absorbance detector.
7.4.5 Performance checks
7.4.5.1 General
The required instrument performance, system performance, detector performance and guard column
performance checks shall be carried out before each sample run and after servicing.
7.4.5.2 Instrument performance checks
Prior to a run of samples and after each service the instrument shall be checked by monitoring the
back pressure and any background conductivity of the system. If these checks show that the check
v
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shall be taken as required by the manufacturer’s instructions.
7.4.5.3 System performance checks
The laboratory shall have a system performance check in which known solutions of mixed anions of
interest, such as 50 mg/l chloride (Cl) and 50 mg/l sulfate (SO 4) are used.
7.4.5.4 Detector performance
The detector performance shall be checked before each sample run and after each service, by running
the detector performance check solution at the start of the run. The peak areas for the anions in the
system performance check on solutions shall be within the required tolerances, otherwise, if outside
the required performance, remedial action shall be taken and the test run again.
7.4.5.5 Guard column performance check
The performance of the guard column is checked by running the system performance check solution
through the guard column. The capacity factor, k, is calculated as the difference in sulfate and
t2 – t1
t1 . The column shall be cleaned
according to the manufacturer’s instructions if k is less than 50% of its value when the machine was
f
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,
.
7.4.6 Calibration
7.4.6.1 Solutions covering the high and low ranges of the calibration shall be prepared from analytical grade
solid reagents including sodium chloride and sodium sulfate. The anion content of the calibration
solution covers the range as in Table 1. However, if other anions are to be analyzed at the same time in
20 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
addition to chloride and sulfate, then they shall be added to the working standard. Freshly prepared
high purity water blanks, as used in the preparation of the samples shall also be analyzed. All the
calibration solutions and blanks shall be traceable to a primary standard, e.g. BS EN ISO 17034.
NOTE 1 Higher concentration stock solutions for each anion might be prepared from which the calibration
solutions are made.
NOTE 2 The typical concentration of calibration ranges defined in this method for inorganic anions are in Table 1.
Table 1
— Example concentration of calibration ranges
Anions
Calibration range
(mg/l)
Chloride (Cl )
2 – 100
‑
7.4.6.2
Table 2
2−
Sulfate ( SO 4
A
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2 – 50
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Table 2.
n
— Example anion concentrations in calibration standards
Working standard
Chloride Cl ‑
Unit
mg/l
mg/l
Standard 1
0.25
0.5
Standard 2
5
25
Standard 3
10
50
Standard 4
20
75
Standard 5
50
100
Sulfate SO 42‑
NOTE Other anions may be added if they are also to be analyzed.
7.4.6.3
The reagents, such as sodium chloride and sodium sulfate solid shall be heated in clean containers
at (105 ±4) °C to constant weight and allowed to cool in a desiccator containing dry self‑indicating
desiccant. Each solution shall be made up for the required concentration using high purity water
t
y
7.4.6.4
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1
8
.
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C
.
A calibration shall be performed for each batch of analyses. The calibrations shall be acceptable if the
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(
r2 ) values are 99.7% or better and their offsets are better than ±0.05. If
the instrument is out of calibration and recalibration is required the instrument shall be shut down
and restarted.
7.4.6.5
A calibration drift check shall be carried out at the end of the analytical run using the midpoint
working standard for each anion (in the case of Table 2 it is Standard 3). The data shall be within 10%
of the target value.
7.4.6.6
7.4.6.7
The concentration of the anions in the test solutions shall not be greater than the calibration range.
The ions of interest shall be separated and measured using a system typically comprising of inline
u
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7.4.7 Test procedure
7.4.7.1
T
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manufacturer’s instructions.
7.4.7.2
7.4.7.3
Freshly prepared water blanks shall be included in the run.
Where necessary, the sample shall be diluted with high purity water either to bring the individual
determinand into the calibrated analytical range or the sample matrix to an acceptable level (for
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 21
BS 1377‑3:2018
BRITISH STANDARD
instance below a maximum total anion content, e.g. 1 000 mg/l total anion content). Details of sample
dilution shall be recorded.
7.4.7.4
7.4.7.5
NOTE Samples that contain moderate or high levels of aluminium, iron or zinc are liable to result in column
contamination, so suspect samples should be pre-analyzed, such as with an ICP method.
The test shall proceed as required by the apparatus manufacturer’s instructions.
All chromatograph data and chromatograms shall be saved on a computer system and inspected for
q
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.
7.4.8 Calculations — Corrections for dilutions and final concentration
Dilution factor (DF) shall be calculated from equation (9) and is the ratio of the volume of the initial
c
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n
.
V2
V1
DF =
(7)
where
V1
V2
ρc = ρi
×
D
is the volume of the undiluted solution;
is the volume of the diluted solution that is tested.
F
(
8
)
where
ρc
ρi
is the concentration of the initial solution;
is the concentration of the diluted solution that is tested.
The dilution factor = 1 if not diluted.
T
h
e
f
i
n
a
l
c
o
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c
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n
t
r
a
t
i
o
n
,
ρ f, is:
ρf = ρc – ρb
(9)
where
is the concentration of the blank solution.
ρb
The blank solution shall not be diluted, but if it is, the sample shall be diluted and this shall be noted.
7.5 Inductively coupled plasma atomic emission spectrometer (ICP-AES) method for
analysis of acid or water extract or groundwater sulfate
7.5.1 General
This method of analysis is suitable for determination of the concentration of sulfur species (Clause 7 )
and magnesium (Clause 10 ) and many other elements in solution. The general method for ICP‑AES,
also known as ICP‑OES, is covered in BS EN ISO 11885, which is intended primarily for water quality.
ICP‑AES measures the concentration of elemental sulfur (S), magnesium (Mg) and copper (Cu), rather
than the concentration of the SO 4 anion per se. The maximum concentration of the different elements
t
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a
t
c
a
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b
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.
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i
g
h
concentrations, dilution shall be diluted.
NOTE Inductively coupled plasma mass spectrometer (ICP-MS) method may also be used. This equipment is
designed to measure very low concentrations, which are not relevant for the purposes of this British Standard.
22 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
e
r
BRITISH STANDARD
BS 1377‑3:2018
7.5.2 Principle
The prepared liquid sample is converted into an aerosol (nebulized), which is transported by a
plasma torch where excitation occurs. Characteristic emission spectra are produced by an inductively
coupled plasma (ICP). The spectra are dispersed by a grating spectrometer and the intensities of the
lines are measured with a detector. The signals from the detector(s) are processed and controlled by
a computer system.
7.5.3 Interferences
To avoid interference with other ions, the method used shall be carefully reviewed to identify if a new
method of sample preparation should be developed to validate the method.
NOTE Several spectrum interference effects at different wavelengths can contribute to inaccuracies in the
determination of elements. For sulfur the interference at a wavelength of 180.669 nm is caused by arsenic (As) and
calcium (Ca) and at a wavelength of 181.975 nm the interference is caused by chromium (Cr) and molybdenum
(Mb). For magnesium the interference at wavelength 279.078 and 279.553 nm is caused by iron (Fe) and
interference at wavelength 285.213 nm caused by chromium (Cr). For copper the interference at wavelength
324.754 nm is caused by molybdenum (Mo), cobalt (Co) and iron (Fe) and at 327.393 nm it is cobalt (Co) and
titanium (Ti). Comparison tests using methods other than ICP-AES may also be used.
7.5.4 Calibration
7.5.4.1 General
All the calibration solutions and blanks shall be traceable to a primary standard, e.g. BS EN ISO 17034.
7.5.4.2 Preparation of calibration solutions
A
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s
.
Typical calibration standards as a % of the upper limit of the apparatus for the various sulfate and
sulfur extractions, and groundwater sulfur, copper and magnesium extractions are given in Table 3.
— The concentration as a % of the upper limit of the apparatus of the different calibration
standards for ICP-AES
Table 3
Standard 1
Standard 2
Standard 3
Standard 4
Standard 5
0.5
2.5
25
50
100
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Table 4 — Example of five calibration
Analyte
o
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s
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n
i
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T
a
b
l
e
4.
standards for copper, magnesium and sulfur
Standard 1
Standard 2
Standard 3
Standard 4
Standard 5
mg/l
mg/l
mg/l
mg/l
mg/l
Cu
2.5
12.5
125
250
500
Mg
2.1
10.6
106
213
425
S
6
30
300
600
1200
7.5.4.3 Preparation of calibration blank
A
1
0
0
m
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a
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e
labelled and the expiry date of the solution shall match the expiry date of the standard(s) used to
prepare the solution.
7.5.4.4 Calibration procedure
Calibration shall be performed at the start of the anlaytical run and validated by Continued
C
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(
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(
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7.5.5
)
.
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s
h
a
l
l
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 23
BS 1377‑3:2018
BRITISH STANDARD
be 0.99 or better. Check standards shall be within prescribed limits as determined by the laboratory
d
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r
i
n
g
m
NOTE
e
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1
0
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s
.
Calibration charts might be automatically created by the apparatus software.
7.5.5 Quality control
The elements of interest shall be analyzed during an analytical run against a relevant working quality
control (QC) check standard, and this shall be prepared in accordance with laboratories operating
p
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shall be carried out in accordance with the requirements of the laboratory operating procedures.
Non‑conformities shall be documented.
7.5.6 Procedure
7.5.6.1 The apparatus shall be checked to ensure that it is in good working order and that checks as required
by the manufacturer and the laboratory's requirements and procedures have been carried out.
7.5.6.2
7.5.6.3
T
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n
s
to be analyzed shall be loaded into the computer software.
T
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out the analysis as required from the prepared solution from Clause 7 and Clause 10 as required. The
software that starts the test procedure shall then be run.
7.5.6.4
O
n
c
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m
p
l
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t
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quality system shall be made.
7.5.7 Data manipulation
7.5.7.1 All the data, mean calculated concentrations and unit information, shall be stored in
suitable software.
7.5.7.2
The raw data shall be checked to ensure that it is within the calibrated range. Any samples that are
7.5.7.3
Median concentrations obtained from blanks analyzed throughout the analytical run shall be
7.5.7.4
If results on one sample differ by no more than 50 mg/l (S), the mean result shall be calculated. If
over range shall be diluted as required and reanalyzed.
calculated and subtracted from sample data as shown in
7.5.8.1 .
they differ more than 50 mg/l the test shall be repeated with two new analytical portions of the soil.
7.5.8 ICP Calculations
7.5.8.1 The correction for dilution shall be calculated from:
ρ
c
=
ρ
i
×
D
F
(
h
e
f
i
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a
l
c
o
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n
t
r
a
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n
0
7.4.8) = 1 if not diluted.
The dilution factor (see
T
1
,
ρ
f
,
i
s
ρ
f
=
ρ
c
–
ρ
b
.
where
ρ
is the concentration of the blank solution.
b
The blank solution shall not be diluted, but if it is, this shall be corrected by using the dilution factor.
R
e
7.5.8.2
c
o
r
d
t
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e
f
i
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n
t
r
a
t
i
o
n
o
f
s
u
l
f
u
r
,
ρ
, (mg/l).
f
The conversion from elemental sulfur to sulfate concentration shall be calculated from equation (11)
and shall be in mg/l:
24 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
)
BRITISH STANDARD
BS 1377‑3:2018
SO 4 = ρ f × 3
(11)
where
7.5.8.3
ρf
is the measured sulfur in mg/l.
As appropriate, the results shall be reported as water‑soluble sulfate in soil (WS) or groundwater
(GWS) in mg/l using equation [12] .
Water‑soluble sulfate (mg/l) = SO 4 (mg/l)
(12)
As appropriate, the results shall be reported as acid‑soluble sulfate in soil (AS) in % using
equation [13]
Acid‑soluble sulfate (%) = SO 4 (mg/l) x 0.01/m 3
(13)
where
SO 4
m3
is the sulfate concentration determined in the test as given in equation [11]
is the mass o f each test specimen used (in g), as defined for the acid-soluble sul fate
test in
7.9.3.1 .
7.6 Gravimetric method for analysis of acid or water extract or groundwater sulfate
7.6.1 Principle
Barium chloride is added to the extract to precipitate the sulfate as barium sulfate, which is then
determined gravimetrically.
7.6.2 Reagents
7.6.2.1 The reagent specified in 7.6.2.2 shall be used, in addition to those listed in 7.3.2.2 or 7.9.2.2 . All
reagents shall be of recognized analytical reagent quality.
7.6.2.2
NOTE Where accurately standardized solutions are required it may be more convenient to obtain them already
standardized in concentrated form and to dilute them as necessary in accordance with the manufacturer’s
instructions.
Barium chloride, 5% (m/V) solution. Dissolve 50 g of barium chloride in 1 l of water. Filter before use
if necessary.
7.6.3 Apparatus
7.6.3.1 The requirements of BS 1377‑1, where appropriate, shall apply to this test method.
7.6.3.2 The apparatus listed in 7.6.3.3 to 7.6.3.6 shall be used in addition to the items listed in 7.3.3.3 or
7.8.4 or 7.9.2.3 .
7.6.3.3 Either:
a)
sintered silica filtering crucible, of porosity grade No. 4 and about 35 mm diameter and
40 mm high; or
b)
high ignition crucible, of 35 mm diameter and 40 mm high, capable of maintaining a constant
mass when heated to (800 ±50) °C.
7.6.3.4
7.6.3.5
7.6.3.6
A suitable means of igniting the precipitate, pre ferably an electric mu ffle furnace capable o f reaching
and maintaining (800 ±50) °C.
Balance, readable to 0.001 g.
Blue litmus paper.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 25
BS 1377‑3:2018
BRITISH STANDARD
7.6.4 Test procedure
7.6.4.1 Each filtrate sample obtained from the water extract procedure described in 7.3.3 or from the
groundwater sample prepared as described in 7.8.2 or from the acid extract as described in 7.9.2.4
shall be analyzed using the procedure described in 7.6.4.2 to 7.6.4.8 .
7.6.4.2 The solution shall be tested with litmus paper and, if necessary made slightly acid by the addition of
20 drops of hydrochloric acid.
7.6.4.3
If necessary, the solution shall be diluted to 300 ml. The solution shall then be brought to the boil
and 10 ml barium chloride solution added drop by drop with constant stirring. The solution shall be
boiling gently until the precipitate is properly formed.
7.6.4.4
The solution shall be left to stand at just below boiling point for at least 30 min, then left to cool to
7.6.4.5
The liquid and precipitate of barium sulfate shall be transferred with extreme care to a previously
room temperature.
ignited and weighed sintered silica filter crucible using suction. Alternatively, the precipitate shall be
trans ferred with extreme care onto a suitable filter paper in the glass filter funnel and filter. In either
case the precipitate shall be washed several times with hot distilled/de‑ionized water (BS 1377‑
1:2016,
) until the washings are free from chloride as indicated by absence of turbidity when a
drop is tested with the silver nitrate solution.
6.1
7.6.4.6
7.6.4.7
7.6.4.8
I f a sintered silica filter crucible is used it shall be removed from the filter flask and dried at 105 °C
to 110 °C for approximately 30 min. The crucible shall be placed in an electric mu ffle furnace and the
temperature raised gradually to 800 °C until no further loss in mass occurs.
I f the precipitate is filtered through a filter paper, the filter paper and precipitate shall be trans ferred
to a previously ignited and weighed crucible. I f an electric mu ffle furnace is used, the crucible
and contents in it at room temperature shall be transferred into the furnace and the temperature
gradually raised to red heat. Ignition for about 15 min at red heat shall usually be su fficient in
either case.
Following
7.6.4.6 or 7.6.4.7, the crucible shall be cooled to room temperature in the desiccator and
weighed to the nearest 0.001 g. The mass of the precipitate (m 4) shall be calculated from the increase
in the recorded mass of the crucible.
7.6.5 Calculations
7.6.5.1 Soil samples
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the equation:
fraction
finer than 2 mm =
m 2 × 100 %
m1
(14)
where
m
1
is the initial dry mass of sample (in g);
m
2
is the mass of the sample passing the 2 mm test sieve (in g).
7.6.5.2 Water extract
The concentration of water‑soluble sulfate (as SO 4) in the fraction o f the soil sample finer than 2 mm
for each determination shall be calculated from the equation:
SO 4 =
m
4
x 8232 (mg/l)
26 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
(15)
BRITISH STANDARD
BS 1377‑3:2018
7.6.5.3 Groundwater
The sulfate content (as SO 4) of the groundwater (in mg/l) shall be calculated from the equation:
SO 4 = m 4 x 8232 (mg/l)
(16)
where
is the mass of ignited precipitate (in g).
m4
7.6.5.4 Acid extract
For the acid extract procedure, the percentage of acid‑soluble sulfate (as SO4) in the fraction of the
s
o
i
l
s
a
m
SO 4 =
p
l
e
f
i
n
e
r
41 . 16 × m 4
m3
t
h
a
n
2
m
m
f
o
r
e
a
c
h
d
e
t
e
r
m
i
n
a
t
i
o
n
s
h
a
l
l
b
e
c
a
l
c
u
l
a
t
e
d
f
r
o
m
t
h
e
e
q
u
a
t
i
o
n
:
(17)
(%)
where
m3
m4
is the mass of each test specimen used (in g);
is the mass of ignited precipitate (in g).
If more than one specimen has been tested and the individual results differ by no more than 0.2%
(SO 4), the mean result shall be calculated. If they differ by more than 0.2%, the test shall be repeated,
starting with two new analytical portions of the soil.
7.7 Ion-exchange method for analysis of water extract or groundwater sulfate
7.7.1 General
The ion‑exchange method is used to analyze 2:1 water‑soluble sulfate and groundwater sulfate. The
requirements of Part 1 of this standard, where appropriate, shall apply to this test method.
NOTE The ion-exchange method cannot be used if the soil or groundwater contains anions of strong acids, such
as chlorides, nitrates and phosphates.
7.7.2 Reagents
7.7.2.1 All reagents shall be of recognized analytical reagent quality.
7.7.2.2
7.7.2.3
7.7.2.4
NOTE Where accurately standardized solutions are required it may be more convenient to obtain them already
standardized in concentrated form and to dilute them as necessary in accordance with the manufacturer’s
instructions.
A strongly acidic cation-exchange resin.
Hydrochloric acid solution [c(HCl) = approximately 4 mol/l] . Dilute 360 ml of concentrated
hydrochloric acid (density 1.18 g/ml) to 1 l with distilled/de‑ionized water (BS 1377‑1:2016, 6.1 ).
Sodium hydroxide solution [c(NaOH) = approximately 0.1 mol/l] . Dissolve about 2 g of sodium
hydroxide (see 7.7.2.1 note) in 500 ml of distilled/de‑ionized water (BS 1377‑1:2016, 6.1 ).
Determine its exact concentration (B) by titration against the potassium hydrogen phthalate solution
(see 7.7.2.5 ) using phenolphthalein or thymol blue as indicator (see Note). Keep the solution in an
airtight container.
WARNING. Sodium hydroxide is strongly caustic; avoid contact with the skin and use eye protection.
NOTE If standardized acid is available, e.g. prepared as described in
, this may be used instead of the
potassium phthalate. Alternatively, it may be more convenient to obtain a ready standardized solution of sodium
hydroxide and prepare it in accordance with the manufacturer’s instructions.
8. 4. 4
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 27
BS 1377‑3:2018
7.7.2.5
BRITISH STANDARD
Potassium hydrogen phthalate solution , [c(KHC 6H 4(COOH) 2 ) = 0.1 mol/l] . Weigh out 5.10 g of
potassium hydrogen phthalate which has previously been dried at between 105 and 110 °C for
2 h, dissolve in distilled/de‑ionized water (BS 1377‑1:2016,
) and dilute to exactly 250 ml in a
6.1
v
o
7.7.2.6
l
u
m
e
t
r
i
c
f
l
a
s
k
.
Indicator solution , e.g. screened methyl orange, which gives a distinct colour change in the range
pH 4 to pH 5.
7.7.2.7
Silver nitrate solution . Dissolve 0.5 g of silver nitrate in 100 ml distilled/de‑ionized water (BS
7.7.2.8
Nitric acid solution, 5% (v/v). Dilute 5 ml of concentrated nitric acid (density 1.42 g/ml) to 100 ml
1:2016,
1377‑
6.1 ). Store the solution in an amber‑coloured glass container.
6.1 ) water.
with distilled/de‑ionized water (BS 1377‑1:2016,
7.7.2.9 Distilled/de-ionized water, of a purity conforming to BS 1377‑1:2016, 6.1 .
7.7.3 Apparatus
7.7.3.1 The apparatus listed in 7.7.3.2 to 7.7.3.7 is required in addition to the items listed in 7.3.2.3 or 7.8.4.
7.7.3.2 Glass ion-exchange column
Figure 1).
7.7.3.3 Water reservoir, incorporating a constant‑head device (optional). A typical design is shown
,
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d
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a
s
w
a
n
-
n
e
c
k
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u
t
l
e
t
(
s
e
e
in Figure 2.
7.7.3.4 Two 500 ml conical beakers.
7.7.3.5 250 ml beaker.
7.7.3.6 50 ml burette and burette stand.
7.7.3.7 Amber-coloured glass container.
7.7.4 Preparation of ion-exchange column
7.7.4.1
f
f
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a
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f
-
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i
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l
stirred with distilled/de‑ionized water (BS 1377‑1:2016,
7.7.4.2
6.1 ) water.
t
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The suspension of resin in water shall be transferred into the column so that when the resin has
settled there is approximately 20 mm depth of water above the resin when the surplus water has
drained away (see Figure 1). This depth of water above the resin shall be maintain at all times.
7.7.4.3
If the constant head device is not available, the cation‑exchange resin shall be activated by leaching
with 100 ml of hydrochloric acid (
7.7.2.3 ) added in increments, followed by washing with
6.1 ) water in increments, taking care not to add further
distilled/de‑ionized water (BS 1377‑1:2016,
liquid until each increment has drained away.
7.7.4.4
Alternatively, if the constant‑head device is available (Figure 2), 100 ml of the acid shall be placed
in the device, the stopper replaced, and left in the apparatus until the acid has passed through the
c
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m
n
.
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c
1377‑1:2016,
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6.1 ) water, and the water left to percolate until the liquid coming from the column gives
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f
nitric acid.
7.7.4.5
After the column has been used for four consecutive determinations the cation‑exchange resin shall
be re‑activated by repeating
7.7.4.3 and 7.7.4.4.
28 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
Figure 1 — Constant-head device for use with ion-exchange column
All dimensions are in millimetres.
Key
1
2
3
4
24/29 stopper
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y
19/26 cone
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 29
BS 1377‑3:2018
BRITISH STANDARD
Figure 2 — Ion-exchange column for sulfate determination
All dimensions are in millimetres.
Key
1
19/26 socket (not required if constant head device is not used)
2
300 if constant head device is used
3
Cation‑exchange resin
4
Glass wool pad
5
Rubber bung bored to take glass tube
7.7.5 Test procedure
7.7.5.1 Each 2:1 water‑soil extract obtained as described in 7.3 , or each groundwater sample obtained as
described in 7.8 , shall be analyzed as given in 7.7.5.2 to 7.7.5.6 .
7.7.5.2 The solution shall be passed through the ion‑exchange column and the column rinsed with two 75 ml
increments of distilled/de‑ionized water (BS 1377‑1:2016, 6.1 ) water.
7.7.5.3 The solution and washings shall be collected in a 500 ml conical beaker placed under the outlet of the
exchange column.
7.7.5.4
7.7.5.5
7.7.5.6
E
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d
the detection of the end‑point in
7.7.5.5 .
t
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f
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r
The solution shall be titrated against the standardized sodium hydroxide solution until the end‑point
is observed.
The volume (V) of sodium hydroxide solution required to neutralize the test solution shall be
recorded to the nearest 0.05 ml.
7.7.6 Calculations
NOTE If no other anions are present, the sulfate content can be expressed in terms of the concentration of sulfate
in the extract.
30 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
7.7.6.1 Water extract
The sulfate content in mg/l of the 2:1 water/soil extract shall be calculated from the equation:
Concentration of sulfate as (SO 4) = 960 BV mg/l
(18)
where
is the concentration of the sodium hydroxide solution in mol/l
is the volume of sodium hydroxide used in ml.
B
V
7.7.6.2 Groundwater
The groundwater sulfate content in mg/l shall be calculated from the equation:
Concentration of sulfate as (SO4) = 480 BV mg/l
(19)
where
B
V
is the concentration of the sodium hydroxide solution in mol/l;
is the volume of sodium hydroxide used in ml.
If more than one test is done per sample and individual results differ by no more than 200 mg/l (SO 4),
the mean result shall be calculated. If they differ by more than 200 mg/l, the test shall be repeated
s
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a
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w
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1
0
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.
7.8 Determination of groundwater sulfate (GWS)
7.8.1 Principle
The groundwater sulfate is a measure of the sulfate ions present in a sample of groundwater.
7.8.2 Preparation of groundwater samples for testing
7.8.2.1 The requirements of BS 1377‑1:2016, where appropriate, shall apply to this test method.
7.8.2.2 Samples shall be stored at between 1 °C and 8 °C.
7.8.3 Reagents
7.8.3.1 1% v/v analytical grade nitric acid, if analysing with ICP or gravimetric methods.
7.8.3.2 0.5% v/v hydrochloric acid, if analysing with ICP or gravimetric methods.
7.8.4 Apparatus
7.8.4.1 Filtration funnel and stand.
7.8.4.2 Filter papers, of a diameter to suit the funnel, Whatman No.44® grade or similar.
7.8.4.3 Three 500 ml glass conical beakers.
7.8.4.4 Two 250 ml conical beakers.
7.8.4.5 100 ml glass measuring cylinder.
7.8.4.6 50 ml pipette.
7.8.4.7 Wash bottle, preferably made of plastics, containing distilled/de‑ionized water (BS 1377‑1:2016, 6.1 ).
7.8.4.8 Suitable size syringe and 0.45 μm syringe filter (for IC and ICP analytical methods).
3)
3
Whatman is a trademark of GE Healthcare. This information is given for the convenience of users of this document and does not constitute
an endorsement by the British Standards Institution of the named product. Equivalent products may be used if they can be shown to lead to
the same results.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 31
BS 1377‑3:2018
BRITISH STANDARD
7.8.5 Procedure
7.8.5.1 The groundwater sample shall usually be 500 ml. The volume of the sample shall be recorded
as V (in l).
7.8.5.2
7.8.5.3
T
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p
T
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s
7.8.6
7.8.6.1
7.8.6.2
7.8.6.3
7.8.6.4
7.8.7
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7.8.5.4
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12 ), and recorded.
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7.3.4, for IC see 7.3.4.2 and 7.4, for ICP see 7.3.4.3 and 7.5 , for gravimetric method see 7.3.4.4 and
7.6 or, for ion exchange column see 7.3.4.5 and 7.7 .
Calculations
For IC see 7.4.8 .
for ICP see 7.5.8 .
For gravimetric method see 7.6.5 .
For ion exchange see 7.7 .
Test report
T
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The test report shall state that the test was carried out in accordance with the sample preparation
given in 7.8.5 , the relevant chemical analysis method and the relevant chemical test method, and shall
contain the following information:
a)
the method of test used;
b)
the average sulfate content of the sample of ground water, to the nearest 10 mg/l;
c)
the pH of the sample of ground water to the nearest 0.1 pH unit; and
d)
the information required by BS 1377‑1:2016, 10.1 .
7.9 Determination of acid-soluble sulfate (AS)
COMMENTARY ON 7.9
Acid-soluble sulfates include gypsum and highly soluble sulfates such as epsomite. The hydrochloric
acid extraction procedure described will not dissolve some sulfate minerals such as barite and sulfur in
organic matter, so the former term “total sulfate” is not used. However, monosulfides such as pyrrhotite
are decomposed by hydrochloric acid and liberate hydrogen sulfide gas (H2S). As the test quantifies the
sulfate in solution, this does not contribute to the amount determined. If required, monosulfide sulfur
may be determined as described in 7.11 .
The acid-soluble sulfate defines the “sulfate reservoir” that can be brought into solution by water over
time. This permits estimation of whether sulfate reactions have the capacity to be long-continued. In
contrast, water-soluble sulfate provides a measure of the likely concentration of sulfate that may arise
in water percolating through ground material containing sulfates. Acid-soluble sulfate does not test for
sulfur species such as pyrite that may alter over time to produce sulfate.
7.9.1 Principle
Excess hydrochloric acid is added to test specimens prepared as given in 7.2.3 , to dissolve all readily
acid‑soluble sulfate species into solution. The sulfate in solution is then determined by one of the
32 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
methods in either the ICP‑AES method given in 7.5 or the gravimetric method given in 7.6 , and is
presented as the acid‑soluble sulfate in % SO 4.
7.9.2 Preparation of the acid: soil extract
7.9.2.1 General
The requirements of BS 1377‑1:2016, where appropriate, shall apply to this test method. All reagents
shall be of analytical grade.
7.9.2.2 Reagents
7.9.2.2.1
Hydrochloric acid, analytical grade concentrated (HCl), 1.18 g/ml (solution = 35% HCl) make up to
25% (v/v) solution. Dilute 250 ml of concentrated hydrochloric acid to 1 l with distilled/de‑ionized
water (BS 1377‑1:2016, 6.1 ) water.
7.9.2.2.2
Dilute ammonia solution . Dilute 500 ml of ammonia (relative density 0.880) to 1 l with distilled/de‑
7.9.2.2.3
Silver nitrate, 0.5% (v/v) solution. Dissolve 0.5 g of silver nitrate in 100 ml of distilled/de‑ionized
ionized water (BS 1377‑1:2016, 6.1 ) water.
water (BS 1377‑1:2016, 6.1 ) water.
7.9.2.3 Apparatus
7.9.2.3.1
Flask
7.9.2.3.2
Distilled/deionized water, of purity conforming to BS 1377‑1:2016,
7.9.2.3.3
Water-cooled condenser.
7.9.2.3.4
Long delivery stem quick fit dropping funnel or a jumbo syringe with a long delivery stem.
7.9.2.3.5
Electric heating mantle (or an alternative heating source).
7.9.2.3.6
Vacuum filter funnel
7.9.2.3.7
0.45 μm membrane syringe filter.
7.9.2.3.8
7.9.2.3.9
,
2
5
0
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l
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4)
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®
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.
30 ml–50 ml capacity clean, acid-proofe.g. sterile polystyrene, polypropylene or high density polyethylene
(HDPE) or similar leak-proof screw cap bottles.
Laboratory glassware.
7.9.2.3.10
De-ionized water, conforming to BS 1377‑1:2016,
7.9.2.3.11
Oxygen-free nitrogen or argon .
7.9.2.3.12
Lead acetate paper.
4
6.1 .
6.1 .
Whatman is a trademark of GE Healthcare. This information is given for the convenience of users of this document and does not constitute
an endorsement by the British Standards Institution of the named product. Equivalent products may be used if they can be shown to lead to
the same results.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 33
BS 1377‑3:2018
BRITISH STANDARD
7.9.2.4 Preparation of acid extract
A 25% hydrochloric acid solution by volume using analytical reagent grade acid and de‑ionized water
shall be prepared. The hydrochloric acid solution shall be de‑aired by passing oxygen‑free nitrogen
(white spot) or argon through it for 10 min prior to use ensuring that the acid does not "bubble out"
of the container. Alternatively, heat the hydrochloric acid solution to boiling, maintain the solution
at boiling point for 10 min and then immediately transfer it to an appropriate sealed vessel, cool and
store until required. Both these operations shall be carried out under safe conditions, for instance in a
fume cupboard or beneath an extractor hood.
7.9.3 Procedure
7.9.3.1 A 0.8 g to 1.0 g representative portion of the oven dried sample (7.2.3.2 ) shall be weighed out
to an accuracy of 0.001 g and recorded as m 3 in g. It shall then be placed into the round bottom
r
7.9.3.2
7.9.3.3
7.9.3.4
7.9.3.5
e
7.9.3.7
7.9.3.8
7.9.3.9
c
t
i
o
n
f
l
a
s
k
.
NOTE If the gravimetric method of measurement is to be used the mass of sample to use depends on the amount
of sulfate present.
T
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c
o
n
n
e
c
t
e
d
t
o
t
h
e
f
l
a
s
k
a
n
d
t
h
e
c
o
n
d
e
n
s
e
r
w
a
t
e
r
f
l
o
w
e
s
t
a
b
l
i
s
h
e
d
.
Exactly 100 ml of 25% de‑aired hydrochloric acid (V1 ) shall be added using the dropping funnel or
syringe through the condenser. At least 10 ml of each batch of de‑aired hydrochloric acid prepared
shall be retained for blank analysis.
The reaction vessel shall be lowered into the heating mantle and the contents brought rapidly
to the boil.
T
b
7.9.3.6
a
h
e
e
r
t
e
e
s
a
c
t
e
t
i
d
o
f
n
o
r
a
t
t
h
b
e
o
p
i
l
r
i
n
e
s
g
e
p
n
o
c
i
e
n
o
t
u
f
h
n
d
y
d
e
r
r
o
r
g
e
e
f
l
n
u
s
x
u
l
s
h
f
i
a
d
l
l
e
b
u
e
s
i
m
n
g
a
l
i
e
n
a
t
a
d
i
n
a
c
e
e
d
f
o
t
a
r
t
e
1
p
5
a
m
p
e
i
n
u
t
e
s
.
T
h
e
e
x
h
a
u
s
t
g
a
s
s
h
a
l
l
r
.
NOTE If this darkens to black, monosulfide minerals are present and this should be included in the test report.
Such minerals may be quantified using methods given in 7.11 .
T
h
e
c
o
n
t
e
n
t
s
o
f
t
h
e
r
e
a
c
t
i
o
n
f
l
a
s
k
s
h
a
l
l
b
e
a
l
l
o
w
e
d
t
o
c
o
o
l
t
o
r
o
o
m
t
e
m
p
e
r
a
t
u
r
e
w
i
t
h
t
h
e
condenser attached.
T
h
e
r
e
s
i
d
u
a
l
s
o
l
u
t
i
o
n
i
n
t
h
e
r
e
a
c
t
i
o
n
f
l
a
s
k
s
h
a
l
l
b
e
f
i
l
t
e
r
e
d
u
n
d
e
r
v
a
c
u
u
m
i
n
t
o
a
d
r
y
f
i
l
t
e
r
f
l
a
s
k
.
NOTE If the filtrate is still cloudy further filtration using a 0.45 μm membrane syringe filter will be necessary. Do
not add any more water.
An aliquot of around 20 ml of the sample shall be retained for sulfate determination.
The sulfate content of the aliquot shall be determined using ICP‑AES (see 7.5 ) or similar equipment
or gravimetric test methods (see 7.6 ).
7.9.4 Test report
The test report shall state that the test was carried out in accordance with the sample preparation
7.9.3 and chemical analysis method given in 7.5 or 7.6 and shall contain the following information:
a)
the method of test used;
b)
the average acid‑soluble sulfate content of the sample of the material to the nearest 0.01%;
c)
the percent by dry mass of the original sample passing a 2 mm sieve to the nearest 1%; and
d)
the information required by BS 1377‑1:2016, 10.1 .
34 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
7.10 Determination of total sulfur (TS)
7.10.1 Principle
The total sulfur (TS) determination measures all the sulfur present in the test sample, whatever form
it is in. The determination is a screening procedure used for the indirect determination of reduced
s
u
l
f
i
d
e
c
o
n
t
e
n
t
a
n
d
t
h
e
d
e
t
e
r
m
i
n
a
t
i
o
n
o
f
t
o
t
a
l
p
o
t
e
n
t
i
a
l
s
u
l
f
a
t
e
(
T
P
S
)
a
s
d
e
s
c
r
i
b
e
d
i
n
7.10.2.5.3 .
7.10.2 High temperature combustion method
7.10.2.1 Apparatus
Total sulfur content may be determined using suitable, commercially available High Temperature
Combustion (HTC) apparatus.
The analyzer shall be capable of reaching temperatures in excess of 2 000 °C within a 40 s
analysis period.
NOTE Such instruments utilize induction furnaces and/or resistance furnace or including dual
furnace technology.
7.10.2.2 Procedure
Test specimens obtained as described in
7.2 shall be tested in accordance with the manufacturer
of the apparatus instructions. The results shall be obtained as total sulfur (TS) directly from the
instrument as % S to the nearest 0.01%.
7.10.2.3 Dilution
If the sulfur content of the sample is beyond the calibration range of the instrument a new sub sample
s
h
a
l
l
b
e
d
i
l
u
t
e
d
w
i
t
h
a
p
u
r
e
m
i
n
e
r
a
l
t
h
a
t
i
s
s
u
l
f
i
d
e
f
r
e
e
,
s
u
c
h
a
s
s
i
l
i
c
a
p
o
w
d
e
r
.
T
h
e
d
i
l
u
t
a
n
t
m
a
t
e
r
i
a
l
shall be dried to between 105 °C and 110 °C until the mass is constant, i.e. when the differences
in successive weighings, carried out at intervals of 4 h, do not exceed 0.1% of the original mass of
.
the sample It shall be allowed to cool in a desiccator containing dry desicant. A suitable quantity
of known mass measured to 0.001 g shall be thoroughly mixed with a subsample of the material as
produced in
7.2 . This mix shall be tested as in 7.10.2.2 .
7.10.2.4 Calibration
Blanks shall be run with samples as a quality check on the performance of the instrument.
Standards of known sulfur content shall be used to calibrate HTC analyzers with a similar range of
mineralogies to those of the test samples and shall be carried out at the beginning and the end of each
series of tests, e.g. twice daily.
7.10.2.5 Calculations
7.10.2.5.1 Soil sample
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the equation:
f
r
a
c
t
i
o
n
f
i
n
e
r
t
h
a
n
2
m
m
=
m 2 × 100 %
m1
(20)
where
m
m
1
is the initial dry mass of sample (in g);
2
is the mass of the sample passing the 2 mm test sieve (in g).
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 35
BS 1377‑3:2018
BRITISH STANDARD
7.10.2.5.2 Corrections for dilutions
Dilution factor shall be calculated using equation (21) and is the ratio of the mass of the initial sub‑
s
a
m
p
l
e
t
h
e
m
a
s
s
o
f
t
h
e
f
i
n
a
l
"
d
i
l
u
t
e
d
"
s
u
b
-
s
a
m
p
l
e
.
ms 2
ms1
Dilution factor DF =
(21)
where
ms1
ms2
T
S
=
i
ρ
×
d
i
l
is the mass of the undiluted sample;
is the mass of the diluted solution that is tested.
u
t
i
o
n
f
a
c
t
o
r
(
2
2
)
where
ρ
is the %S from the instrument.
i
7.10.2.5.3 Calculation of Total Potential Sulfate (TPS)
The total potential sulfate (TPS) shall be calculated from the total sulfur content (TS) as:
TPS (% SO 4 ) = TS(%S) × 3
(23)
7.10.2.6 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018, 7.10 and
shall contain the following information:
a)
the method of test used and model of instrument used;
b)
the total sulfur content (TS) to the nearest 0.01% (as S) of the oven‑dry mass of soil passing a 2
mm test sieve;
c)
the total potential sulfate (TPS) to the nearest 0.1% (as SO 4) of the oven‑dry mass of soil passing
a 2 mm test sieve;
d)
the percentage by dry mass of the original sample passing a 2 mm test sieve, to the
nearest 1%; and
e)
the information required by BS 1377‑1:2016, Clause 10.1 .
7.11 Determination of total reduced sulfur (TRS)
7.11.1 Principle
R
e
t
h
l
e
d
e
a
u
s
d
c
u
i
e
l
n
d
f
g
u
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t
o
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f
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t
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d
y
d
t
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o
s
r
a
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r
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g
o
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f
e
n
c
o
x
s
t
r
u
p
l
p
a
f
i
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c
t
e
d
r
e
s
d
f
g
a
u
l
f
i
r
o
s
,
d
m
t
h
w
h
e
.
T
i
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e
h
e
s
i
a
a
s
m
r
m
p
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o
a
u
l
e
c
n
b
t
e
t
y
d
o
f
a
c
w
s
i
u
i
d
t
h
l
f
u
i
f
i
a
r
e
c
i
d
i
d
s
c
i
q
h
f
i
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e
a
o
d
n
m
c
t
i
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f
i
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p
e
m
p
d
(
e
I
r
b
y
I
)
n
i
d
s
o
t
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u
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t
i
n
g
i
t
h
o
n
t
h
e
loss of copper from the solution using ICP‑AES or similar equipment. The procedure gives the total
reduced sulfur (TRS) content of the sample as % S. From this, the quantity of sulfate that could be
generated by oxidation of the reduced sulfur (OS, % SO 4
f
7.11.2.2 , equation [30] .
)
u
r
t
h
e
r
d
e
f
i
n
e
d
i
n
7.11.2 Reagents
7.11.2.1 Oxygen-free (white spot) nitrogen or argon gas.
7.11.2.2 20–30 mesh pure zinc (Zn).
7.11.2.3 5% Hydrochloric acid (HCl).
36 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
c
a
n
b
e
c
a
l
c
u
l
a
t
e
d
.
O
S
(
O
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d
i
s
a
b
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S
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l
f
i
d
e
s
)
i
s
BRITISH STANDARD
7.11.2.4
7.11.2.5
7.11.2.6
BS 1377‑3:2018
Distilled or de-ionized water, conforming to BS 1377‑1:2016, 6.1 .
Absolute ethanol (C 2 H 5 OH).
Mercuric nitrate [mercury (II) nitrate 2-hydrate: Hg 2(NO3) 2.2H2O] or mercuric chloride [mercury (II)
chloride: HgCl2].
Analytical grade chromic chloride (chromium (III) chloride 6‑hydrate: CrCl 3 .6H 2 O).
Analytical grade concentrated hydrochloric acid, 1.18 g/ml (solution = 36 – 38% HCl).
Analytical grade copper nitrate [copper (II) nitrate 3‑hydrate: Cu(NO 3 ) 2 .3H 2 O] .
Analytical grade concentrated nitric acid, 1.42 g/ml (solution = 70% HNO 3 ).
Lead acetate paper.
7.11.2.7
7.11.2.8
7.11.2.9
7.11.2.10
7.11.2.11
7.11.3 Apparatus
7.11.3.1 The apparatus required for the test is shown in Figure 3 .
7.11.3.2 250 ml capacity 2 neck quick fit reaction flask.
7.11.3.3 75 ml quick fit reagent reservoir with airtight tap or jumbo syringe attachment.
7.11.3.4 Tapered quick fit air inlet tube.
7.11.3.5 Condenser.
7.11.3.6 Sulfur resistant tubing. Only H S‑resistant line (consult manufacturer about suitability) shall be used
2
for connection from condenser to the absorption cell. The gas line shall be suitably attached to all
connections producing airtight joints.
7.11.3.7
2 No 75 ml trapping vessels: Dreschel type sintered bottle head with a sintered disc of porosity grade
P
7.11.3.8
7.11.3.9
7.11.3.10
7.11.3.11
7.11.3.12
7.11.3.13
5
4
0
(
s
e
e
B
S
1
7
5
2
)
i
n
a
q
u
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c
k
f
i
t
t
e
s
t
t
u
b
e
a
s
s
e
m
b
l
y
.
300 ml conical glass flask.
Heating mantle or other suitable heat source.
Type 2c chromatography column (for the Jones reductor).
Filter funnel
Laboratory glassware.
Vacuum pump or supply.
,
5
0
0
m
l
c
a
p
a
c
i
t
y
f
l
a
s
k
a
n
d
W
h
a
t
m
a
n
N
o
.
5
4
0
5)
®
(
o
r
e
q
u
i
v
a
l
e
n
t
)
f
i
l
t
e
r
p
a
p
e
r
.
Whatman is a trademark of GE Healthcare. This information is given for the convenience of users of this document and does not constitute
an endorsement by the British Standards Institution of the named product. Equivalent products may be used if they can be shown to lead to
the same results.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 37
BS 1377‑3:2018
BRITISH STANDARD
Figure 3 — Schematic diagram of the apparatus for total reduced sulfur determination
All dimensions are in millimetres.
Key
1
2
r
2
3
0
a
c
m
t
i
l
o
2
n
n
f
l
e
a
c
s
k
q
u
i
c
k
f
i
t
5
5
n
m
t
r
o
l
d
q
u
u
c
i
c
e
k
f
i
d
Sulfur resistant tubing
k
6
with airtight tap or jumbo
syringe attachment
Nitrogen/argon gas
7
7
i
4
5
e
t
v
i
r
e
a
q
a
u
g
i
e
c
n
t
k
f
i
No 75 ml Dreschel head gas bubbler type trapping vessels
Heating mantle
t
side arm spout
Condenser
7.11.4 Preparation of sulfide extract Jones reductor (see Figure 4)
7.11.4.1 Preparation of the reductor shall be carried out in a fume cupboard or beneath a suitable
extractor hood.
7.11.4.2
7.11.4.3
200 g of 20–30 mesh pure zinc shall be placed in a beaker, washed and decanted twice with 5% by
volume hydrochloric acid, then covered with 200 ml of 5% by volume hydrochloric acid.
NOTE
The zinc amalgam should have a shiny appearance.
The required quantity of mercuric nitrate or mercuric chloride to make a 2% solution (2 g in 200 ml)
shall be added. It shall be stirred for 3‑5 minutes, and the solution decented. It shall be washed and
decanted a further 3 times using de‑ionized water.
38 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
7.11.4.4
The Jones reductor shall be prepared by packing the amalgamated zinc into the glass column and
stored under de‑ionized water containing 1–2 drops of concentrated hydrochloric acid.
7.11.4.5
The Jones reductor shall be activated immediately prior to use. To do this, slowly pass through it
100 ml of 5% by volume hydrochloric acid.
Figure 4 — Jones reductor assembly
All dimensions are in millimetres.
Key
1
2
Glass column
To vacuum pump
7.11.5 Reagent preparation
7.11.5.1 Chromium (III) solution , 266 g/l chromic chloride solution acidified to 4.5% by volume with
7.11.5.2
7.11.5.3
concentrated hydrochloric acid. Dissolve (266 ±0.5) g of chromic chloride in 200 ml of de‑ionized
water (see BS 1377‑1), add 45 ml of analytical grade concentrated hydrochloric acid and make up to
1 000 ml in a volumetric flask with distilled/de-ionized water (BS 1377-1:2016, 6.1 ) water.
Chromium (II) solution . Pass the chromium (III) solution through the activated Jones reductor. On
reduction, the chromic (III) solution changes valence state to chromic (II), which is accompanied by a
colour change from green to blue. Due to atmospheric oxidation this solution is unstable and should
be prepared every two to three days. The solution shall be stored in a stoppered amber glass vessel
out of direct light, preferably in a dark cupboard.
NOTE Chromium (II) solution is highly unstable and will oxidise to Chromium (III) unless stored in airtight glass
containers in the absence of light.
Copper nitrate solution , 200 mg/l acidified to 3.15% with concentrated nitric acid. Dissolve exactly
0.76 g o f copper nitrate in 200 ml o f de-ionized water, trans fer to a volumetric flask, add 31.5 ml o f
analytical grade concentrated nitric acid and make up to 1 000 ml with de‑ionized water (BS 1377‑1).
7.11.6 Test procedure
7.11.6.1 500 mg representative portion of the oven‑dried sample (7.2 ) shall be weighed to an accuracy of
0.0001 g and recorded in mg as m 3. Also, a blank with no sample shall be run.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 39
BS 1377‑3:2018
7.11.6.2
7.11.6.3
7.11.6.4
7.11.6.5
7.11.6.6
7.11.6.7
T
p
l
e
s
h
a
l
l
b
e
p
l
a
c
e
d
i
n
a
2
5
0
m
l
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i
c
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f
i
t
,
s
i
d
e
a
r
m
r
o
u
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d
b
o
t
t
o
m
r
e
a
c
t
i
o
n
f
l
a
s
k
a
n
d
a
d
d
1
0
m
l
)
a
n
d
t
h
e
c
o
n
d
e
n
s
e
r
w
a
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e
r
f
l
o
w
e
s
t
a
b
l
i
s
h
e
d
.
E
a
c
h
t
r
a
p
p
i
n
g
v
e
s
s
e
l
s
h
a
l
l
c
o
n
t
a
i
n
e
x
a
c
t
l
y
5
0
m
l
f
o
2
0
0
m
g
/
l
a
c
i
d
i
f
i
e
d
c
o
p
p
e
r
n
i
t
r
a
t
e
s
o
l
u
t
i
o
n
(combined total of 100 ml recorded as V2).
Exactly 100 ml of the copper nitrate solution shall be retained for a blank determination and shall be
recorded as V1 .
To the side arm a gas inlet tube shall be connected to the oxygen‑free nitrogen (or argon) gas supply,
n
d
a
s
l
o
w
s
t
e
a
d
y
f
l
o
w
f
o
g
a
s
e
s
t
a
b
l
i
s
h
e
d
.
NOTE A carrier gas flow rate should be established which creates a steady flow of gas bubbles from the sinter
head and does not create frothing at the surface of the absorbent solutions contained in the gas traps. This will vary
with use of the sintered heads and generally a supply pressure of between 20–35 kPa has been found suitable.
T
h
e
r
T
h
e
g
o
n
n
c
e
o
n
A
t
n
r
e
a
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d
s
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n
a
a
i
l
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o
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l
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h
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r
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l
y
d
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f
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0
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e
5
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a
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a
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quantity of liquid in the dropping funnel and switching on the gas supply.
The reaction shall be allowed to proceed at room temperature for 15 min then heat (about 150 °C)
a
7.11.6.13
7.11.6.14
m
NOTE An airtight seal should be con firmed prior to testing by setting up the equipment and placing a small
quantity of liquid in the dropping funnel and switching on the gas supply.
a
7.11.6.12
a
Using airtight sulfur resistant tubing, the two in‑line gas washing tube trapping vessels shall
be connected.
c
7.11.6.11
s
The condenser shall be connected (see Figure 3
t
h
7.11.6.10
e
of absolute ethanol.
a
7.11.6.8
7.11.6.9
h
BRITISH STANDARD
p
T
p
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e
d
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a
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.
5
c
h
.
h
will cause the paper to darken to black.
NOTE
If this occurs, the flow rate should be reduced and the fact reported.
If darkening of the lead acetate paper persists the test shall be repeated with a smaller sample.
The volumes of copper nitrate solution shall be accurately measured out using a calibrated pipette.
NOTE 1 The reaction digestion vessel should be washed out as soon as it is cool enough to be handled as the
contents may solidify.
NOTE 2 200 mg/l copper nitrate absorbent solution is suitable for samples with up to 1.7% TRS for a 0.5 g
sample (3.18% equivalent FeS if the sulfide is pyrite). If higher quantities of TRS are expected or detected the
determination should be repeated using smaller quantities of sample, e.g. 0.3 g or using 500 mg/l or 1 000 mg/l
copper nitrate solutions.
2
7.11.6.15 Extracts from such samples shall be appropriatly diluted for ICP‑AES analysis.
7.11.7 Determination of sulfide in extract by determination of copper using ICP-AES
7.11.7.1 When the digestion has been completed, if ICP‑AES or similar analysis is to be used, the contents of
e
7.11.7.2
a
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h
T
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T
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b
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e
5
e
d
0
0
m
w
a
w
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v
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d
d
e
40 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
l
u
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.
BRITISH STANDARD
7.11.7.3
NOTE
T
i
7.11.7.4
7.11.7.5
7.11.7.6
BS 1377‑3:2018
h
n
e
The black solid CuS precipitate on the filter paper should be discarded.
b
t
h
l
e
a
n
v
o
k
l
u
a
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m
d
e
a
t
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b
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c
s
o
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a
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k
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t
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r
a
m
l
i
l
n
b
a
e
t
i
m
o
a
n
recorded as d1 and for the absorbent as d2.
d
o
e
f
u
c
o
p
p
t
o
p
e
5
r
.
0
T
0
h
m
e
l
d
i
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l
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t
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d
n
e
-
f
a
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d
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[
a
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e
k
.
×
s
h
5
a
l
d
l
i
l
b
u
t
i
o
n
]
e
The copper concentration in the blank and absorbent solutions shall be analysed using ICP‑AES (see
7.3.4.3 and 7.5 ).
The results shall be recorded as mg/l of copper in the blank solution as r1 and in the absorbent
solution as r2.
If dilution of the sample is necessary for ICP‑AES analysis it shall be reported, and the total
concentration value shall be corrected (see 7.5.8.1 ).
7.11.8 Calculations
7.11.8.1 Soil sample
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the formula:
f
r
a
c
t
i
o
n
f
i
n
e
r
t
h
a
n
2
m
m
m2
m1
=
(24)
× 100 %
where
m1
m2
is the initial dry mass of sample (in g);
is the mass of the sample passing the 2 mm test sieve (in g).
7.11.8.2 Total reduced sulfur
The amount of sulfur equivalent to the loss of copper from the solution shall be determined from the
reaction and the atomic weights of copper and sulfur using the following equation:
FeS 2 + 2 H 2 = 2 H 2 S + 2 Cu( NO3 ) 2 = 2 CuS + H 2
(25)
Determined precipitate (ppt) = for every g of Cu, 0.504 g of S has been precipitated.
V1 = volume of blank absorption solution in mg/l (normally 100)
V2 = volume of test absorption solution in mg/l (normally 100)
m 3 = weight of test sample in mg (normally 500)
r1 = concentration of copper in the diluted blank solution in mg/l
r2 = concentration of copper in the diluted test solution in mg/l
d1
f
d2
f
Calculate the concentration of copper in the blank solution Tr1 = r1 d1
Calculate the concentration of copper in the test solution Tr2 = r2 d2
=
d
i
l
u
t
i
o
n
o
b
l
=
d
i
l
u
t
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t
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n
n
(
(
n
n
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r
r
m
m
a
l
a
l
l
y
l
y
×
×
5
5
)
)
×
×
Convert concentrations of the solutions used into amount of copper in test quantity.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 41
BS 1377‑3:2018
BRITISH STANDARD
The quantity of copper in the blank solution in mg Cu, p 1 , is given by:
p1
=
Tr1 × V1
(26)
1000
The quantity of copper in the test solution in mg Cu, p 2 , is given by:
p2 =
Tr2 × V2
(27)
1000
NOTE As one atom of sulfur combines with one atom of copper, the quantity of sulfur liberated in the reaction
may be determined from the quantity of copper used.
This value shall be determined in mg S to an accuracy of 0.01 mg and record as m 4:
m 4 = 0 . 504( p1 − p 2 )
(28)
This value shall be divided by the test sample mass, m 3, to obtain the total reduced sulfur (TRS). This
value shall be recorded in %S to the nearest 0.01%:
m4
TRS(%S) =
T
h
e
o
x
i
d
i
s
× 100
m3
a
b
l
e
s
u
l
f
i
d
(29)
e
s
(
O
S
)
s
h
a
l
l
b
e
c
a
l
c
u
l
a
t
e
d
i
n
%
S
O
to the nearest 0.01%:
4
OS(%SO 4 )=TRS×3
(30)
7.11.9 Test report
7.11 and
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018,
shall contain the following information:
a)
the method of test used;
b)
the total reduced sulfur content (TRS) to the nearest 0.01% (as S) of the oven‑dry mass of soil
passing a 2 mm test sieve;
c
)
t
h
e
o
x
i
d
i
s
a
b
l
e
s
u
l
f
i
d
e
s
(
O
S
)
t
o
t
h
e
n
e
a
r
e
s
t
0
.
0
1
%
(
a
s
S
O
4
) of the oven‑dry mass of soil passing a 2
mm test sieve;
d)
the percentage by dry mass of the original sample passing a 2 mm test sieve, to the
nearest 1%; and
e)
10.1 .
the information required by BS 1377‑1:2016,
7.12 Determination of acid-soluble sulfides (monosulfide sulfur) (MS)
7.12.1 Principle
M
T
o
h
n
e
o
h
s
u
y
d
l
f
i
r
d
o
e
g
e
s
n
a
r
s
e
u
l
e
f
i
v
o
d
e
l
v
e
i
s
d
t
r
a
a
s
p
g
a
p
e
s
e
d
o
b
u
y
s
p
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r
y
d
e
c
i
r
p
o
i
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t
a
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n
t
i
o
s
u
n
l
a
f
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s
d
c
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o
b
p
y
p
t
r
e
r
e
s
a
u
t
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l
n
f
i
g
d
e
t
h
a
e
n
s
d
a
m
t
h
p
e
l
q
e
u
w
a
n
i
t
h
t
i
h
t
y
y
d
d
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o
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l
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n
r
e
i
c
d
a
b
c
y
i
d
.
t
h
e
reduction in concentration of copper in the trapping solution. This is combined with determination of
acid‑soluble sulfate for convenience, but can be performed on its own if required.
NOTE Monosulfides are highly reactive and are important in certain situations, e.g. if the mineral pyrrhotite (FeS)
is present, and in estuarine, and organic sediments from marshes, bogs and peat.
7.12.2 Reagents
7.12.2.1 Oxygen free nitrogen or argon
7.12.2.2 Copper nitrate [Cu (II) nitrate 3-hydrate: Cu(NO ) .3H O] .
g
a
s
w
i
t
h
t
a
p
e
r
e
d
q
u
3 2
i
c
k
-
f
i
2
42 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
t
a
i
r
t
i
g
h
t
i
n
l
e
t
t
u
b
e
;
BRITISH STANDARD
BS 1377‑3:2018
7.12.2.3 Analytical grade concentrated nitric acid: 1.42 g/ml (solution = 70% HNO ).
7.12.2.4 Analytical grade concentrated hydrochloric acid: 1.18 g/ml (solution = 35% HCl).
7.12.2.5 Tin (II) chloride [Tin (II) chloride dihydrate: SnCl .2H O] .
7.12.2.6 Distilled or de-ionized water conforming to BS 1377‑1:2016, 6.1 .
7.12.3 Apparatus
7.12.3.1 2 neck quick-fit reaction flask, 250 ml capacity.
7.12.3.2 Quick-fit reagent reservoir, 75 ml capacity with airtight tap or jumbo syringe attachment.
7.12.3.3 Condenser.
7.12.3.4 Sulfur resistant rubber tubing. Use only H S‑resistant tubing (consult manufacturers about suitability)
3
2
2
2
for connection from condenser to the absorption cell as other rubber lines may react giving off sulfur‑
bearing gas. The gas line shall be suitably attached to all connections producing airtight joints.
7.12.3.5
7.12.3.6
7.12.3.7
7.12.3.8
7.12.3.9
7.12.3.10
7.12.3.11
Dreschel type sintered bottle headed trapping vessel, 75 ml capacity with sintered disc porosity grade
40 (BS 1752:1983) in a quick-fit test tube assembly.
Electric mantle heater or similar heating device.
Vacuum filter funnel and Whatman® No 540 6) (or equivalent) filter paper.
0.45 μm membrane syringe filter.
Laboratory glassware.
Lead acetate paper.
Vacuum pump or supply.
NOTE
6
The apparatus is assembled as shown in Figure 5.
Whatman is a trademark of GE Healthcare. This information is given for the convenience of users of this document and does not constitute
an endorsement by the British Standards Institution of the named product. Equivalent products may be used if they can be shown to lead to
the same results.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 43
BS 1377‑3:2018
BRITISH STANDARD
Figure 5 — Apparatus for determination of acid-soluble mono-sulfide (MS)
All dimensions are in millimetres.
Key
1
250 ml 2 neck quick fit reaction flask
5
Sulfur resistant tubing
2
75 ml quick fit reagent reservoir with
6
75 ml Dreschel head gas bubbler type
3
airtight tap or jumbo syringe
trapping vessel
Nitrogen/argon gas introduced via quick fit 7
Heating mantle
side arm spout
4
Condenser
7.12.4 Procedure
7.12.4.1 200 mg/l copper nitrate solution shall be prepared, acidified to 3.15% by volume with analytical
grade concentrated nitric acid: Dissolve 0.76 g of copper nitrate in 200 ml de‑ionized water.
7.12.4.2
7.12.4.3
This shall be trans ferred to a volumetric flask, and 31.5 ml o f analytical grade concentrated nitric acid
shall be added and made up to 1 000 ml with de‑ionized water.
A 25% by volume hydrochloric acid solution shall be prepared using analytical grade concentrated
hydrochloric acid and de‑ionized water. The hydrochloric acid solution shall be de‑aired by passing
oxygen‑free nitrogen or argon through it for 10 min prior to use. Alternatively, the hydrochloric acid
solution shall be prepared beforehand by heating to boiling.
7.12.4.4
The solution shall be maintained at boiling point for 10 min and then the de‑aired solution shall be
7.12.4.5
Between 0.8 g and 1.0 g of powdered oven‑dried sample shall be weighed to 0.0001 g and recorded as
transferred to an appropriate sealed storage vessel until required.
m 3 in g. A blank with no sample shall also be run.
44 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
7.12.4.6
7.12.4.7
7.12.4.8
7.12.4.9
7.12.4.10
BS 1377‑3:2018
The sample shall be placed in the reaction flask and approximately 1.6 g to 2 g o f tin (II)
chloride added.
The condenser (see Figure 5 ) shall be connected and the condenser water flow established.
Using airtight sulfur resistant tubing, the condenser shall be connected to an in‑line gas washing tube
trapping vessel containing exactly 50 ml o f the 200 mg/l acidified copper nitrate solution (V2 ). Exactly
50 ml of the copper nitrate solution shall be retained for a blank determination of copper (V1 ).
NOTE An airtight seal should be con firmed prior to testing by setting up the equipment and placing a small
quantity of liquid in the dropping funnel and switching on the gas supply.
The side arm shall be attached to a gas inlet tube of an oxygen‑free (white spot) nitrogen (or argon)
gas supply tube and a slow steady flow o f gas established.
NOTE A carrier gas flow rate should be established which creates a steady flow of gas bubbles from the sinter
head and does not create frothing at the surface of the absorbent solutions contained in the gas traps. This will vary
with use of the sintered heads and generally a supply pressure between 20 – 35 kPa. Flush the reaction vessel for 5
min to displace the air.
7.12.4.3
The gas flow shall be stopped and exactly 100 ml 25% de-aired hydrochloric acid (see
) (dV1 )
shall be added using the dropping funnel or jumbo syringe through the condenser and the gas flow
re‑started. A 10 ml quantity of each batch of de‑aired hydrochloric shall be retained and prepared for
blank analysis.
7.12.4.11
NOTE If the quick fit dropping funnel tap or syringe connection does not create an airtight seal when the gas
flow is resumed then the dropping funnel should be removed and the inlet port blocked using an airtight quick
fit stopper.
The reaction vessel shall be lowered onto the heating mantle and the contents brought rapidly to
the boil. The reaction shall be maintained at boiling point under reflux for 30 min. The exhaust gas
shall be tested with lead acetate paper for hydrogen sulfide gas, this is indicated by the paper going
to black and if this occurs the test shall be stopped and reported in "remarks". Where this occurs, the
test shall be repeated with a new sample using a reduced gas flow rate. I f a fter reducing the gas flow
rate hydrogen sulfide continues to be present, the tests shall be stopped and repeated using a smaller
amount of sample.
7.12.4.12
The volumes of copper nitrate solution used shall be accurately measured out using a
calibrated pipette.
7.12.4.13
The contents o f the reaction flask shall be allowed to cool to room temperature with the
7.12.4.14
The copper nitrate absorption trap solution shall be filtered and the residue retained on the filter
7.12.4.15
7.12.4.16
condenser attached.
paper shall be washed with de‑ionized water. The blank and absorbent solutions shall be diluted for
copper determination by ICP‑AES or similar method as required.
NOTE The blank and absorbent solutions should be diluted by placing 50 ml quantities of the stock and test
solutions in 250 volumetric flasks and making these up to 250 ml with de-ionized water. Dilution is × 5: respectively
d1 for the blank and d2 for the absorbent solution.
The copper concentrations shall be determined by ICP‑AES or similar equipment (see 7.5 ) as r1 for
the blank and r2 for the absorbent solutions in mg/l.
The monosulfide sul fur content (MS) shall be calculated and presented as % MS.
NOTE The acid-soluble sulfate (AS) value can be determined by filtering the extract solution under vacuum into a
dry filter flask. If the filtrate is cloudy, filter using a 45 μm syringe. Do not add any more water. Retain an aliquot of
about 20 ml and determine the acid-soluble sulfate content as described in 7.9.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 45
BS 1377‑3:2018
BRITISH STANDARD
7.12.5 Calculations
7.12.5.1 Sample
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the formula:
f
r
a
c
t
i
o
n
f
i
n
e
r
t
h
a
n
2
m
m
m2
m1
=
× 100
(31)
where
m1
m2
is the initial dry mass of sample (in g);
is the mass of the sample passing the 2 mm test sieve (in g).
7.12.5.2 Acid-soluble sulfides (monosulfide sulfur)
The amount of sulfur equivalent to the loss of copper from the solution shall be determined by
considering the reaction and the atomic weights of copper and sulfur:
H 2 S + 2 Cu( NO 3 ) 2 = 2 CuS + H 2
(32)
The procedure includes the calculation of the amount of acid‑soluble sulfur and sulfate (AS) and
m
o
n
o
s
u
l
f
i
d
e
(
M
S
)
.
V1 = volume of blank absorption solution in ml (normally 50)
V2 = volume of test absorption solution in ml (normally 50)
m 3 = weight of test sample in mg (normally 1 000)
r1 = concentration of copper in blank solution in mg/l
r2 = concentration of copper in test solution in mg/l
d1
f
f
d2 =
f
f
sr1 = concentration of sulfur in the diluted digested sample in mg/l
dV1 = 100 ml hydrochloric acid
=
d
d
NOTE
i
i
l
l
u
u
t
i
t
i
o
o
n
n
a
a
c
c
t
o
t
o
r
r
o
o
b
a
l
a
b
n
s
k
o
r
s
b
o
e
l
u
n
t
t
i
s
o
o
n
l
u
u
s
t
i
e
o
d
n
i
u
n
s
I
e
C
d
P
i
-
n
A
I
E
C
S
P
(
-
n
A
o
E
r
S
m
(
a
n
l
o
l
y
r
×
m
a
5
l
l
)
y
×
5
)
0.001 mg/g water = 1 mg/l
Determined precipitate (ppt) = for every g of Cu, 0.504 g of S has been precipitated.
The concentration of copper in the blank solution shall be calculated from Tr1 = r1 x d1
The concentration of copper in the test solution shall be calculated from Tr2 = r2 x d2
The concentrations of the solutions used shall be converted into amount of copper in test quantity by
using equations (33) and (34):
46 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
The quantity of copper in the blank solution in mg Cu, p 1 , is given by:
p1
Tr1 × V1
=
(33)
1000
The quantity of copper in the test solution in mg Cu, p 2, is given by:
Tr2 × V2
p2 =
(34)
1000
As one atom of sulfur combines with one atom of copper, the quantity of sulfur liberated in the
reaction may be determined from the quantity of copper used. Determine this value in mg S to an
accuracy of 0.01 mg and record as m 4.
m 4 = 0 . 504( p1 − p 2 )
(35)
This value is divided by the test sample mass, m 3
,
t
o
o
b
t
a
i
n
t
h
e
m
o
n
o
s
u
l
f
i
d
e
s
u
l
f
u
r
(
M
S
)
.
R
e
c
o
r
d
t
h
i
s
value in % S to the nearest 0.01%.
MS(%S) =
NOTE
m4
× 100
m3
(36)
See 7.9 for the calculation of acid-soluble sulfate.
If the acid‑soluble sulfate is also being determined, calculate the amount of sulfur in the digested
solution in mg S and record as m 5.
sr1 × dV1
m5 =
(37)
1000
Convert m 5 to the acid‑soluble sulfur in the sample in % S to the nearest 0.01% and record as m 6.
 m5 
 × 100
 m3 
m6 = 
(38)
Convert m 6 to the acid‑soluble sulfate (AS) in % SO 4 to the nearest 0.01% and record as AS.
AS = 3 × m 6
(39)
7.12.6 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018,
shall contain the following information:
a)
the method of test used;
b
t
h
)
e
m
o
n
o
s
u
l
f
i
d
e
s
u
l
f
u
r
c
o
n
t
e
n
t
(
M
S
)
t
o
t
h
e
n
e
a
r
e
s
t
0
.
0
1
%
(
a
s
S
)
o
f
t
h
e
o
v
e
n
-
d
r
y
m
a
s
s
7.12 and
o
f
s
o
i
l
passing a 2 mm test sieve;
c)
the percentage by dry mass of the original sample passing a 2 mm test sieve;
d)
the acid‑soluble sulfate shall be reported as described in
e)
the information required by BS 1377‑1:2016,
10.1 .
7.9 ; and
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 47
BS 1377‑3:2018
BRITISH STANDARD
8 Determination of the carbonate content
8.1 Types of test method
This clause describes three test methods for the determination of calcium carbonate content of
soil and rocks:
a)
Thermal decomposition of the carbonate method (
8.2 ), which produces carbon dioxide and is
measured with a detector. This is the preferred method and is suitable for rocks or soils.
b)
Rapid titration method for determination of calcium carbonate content (
8.3 ), which is a
screening method suitable for rock and soils with more than 10% carbonate content (m/m ),
a
n
w
i
d
w
h
t
h
a
e
r
k
n
e
o
a
n
w
n
a
c
q
c
u
u
a
r
a
n
t
i
c
y
t
y
o
o
f
f
a
a
b
c
o
i
u
d
t
t
o
1
%
f
i
n
i
a
s
l
i
s
u
t
y
.
f
f
i
T
c
h
i
e
e
n
a
t
.
m
I
o
n
u
t
h
n
t
i
s
o
f
m
e
e
t
h
x
c
e
o
s
d
s
t
h
a
c
i
e
d
s
i
o
s
i
l
d
s
e
p
t
e
e
r
c
i
m
m
i
e
n
n
e
d
i
s
b
t
r
y
e
t
i
a
t
e
t
r
a
d
t
i
o
n
against sodium hydroxide. The result is calculated in terms of the equivalent proportion of
carbon dioxide.
c)
Gravimetric method for determination of calcium carbonate content (
8.4), as described for
hardened concrete in BS 1881‑124, to which reference is made. In the gravimetric method the
carbon dioxide evolved when the rock or soil is treated with hydrochloric acid is passed through
a granular absorbent which enables the mass of carbon dioxide to be determined gravimetrically.
The thermal decomposition method may be used to determine the carbonate content of siderite
(FeCO 3 ), ankerite Ca(Fe,Mg,Mn)(CO 3 ) 2 , dolomite CaMg(CO 3 ) or other carbonate minerals as separate
mineral species. However, the rapid titration and gravimetric methods only determine the calcium
carbonate content.
NOTE The thermal decomposition of carbonate species may be undertaken which is particularly useful when
evaluation of structural heave due to the expansion of fill containing pyrite and other sulfide minerals is being
considered, where calcium carbonate buffers the products of sulfide oxidation to produce gypsum.
8.2 Total carbon analyzer, combustion method — Total inorganic carbon (TIC)
8.2.1 Principle
This procedure covers the determination of the percentage of total inorganic carbon (TIC) present in
a sample by total carbon analyzer using the decomposition of carbonate and combustion of organic
material method. The total carbon content (TC), i.e. the organic and inorganic carbon is determined
on the whole sample. Another subsample is then treated with acid to remove inorganic carbon and
the procedure repeated to give the total organic carbon, TOC, as described in Clause 5 . The total
inorganic carbon, TIC, is then calculated as the difference:
TC – TOC = TIC
(40)
The carbonate content is then calculated from the total inorganic carbon (TIC).
8.2.2 Preparation of sample
Samples shall be prepared in accordance with BS 1377‑1:2016,
8.2.2.1 Reagents
The reagents as listed in
5.2 shall be used.
8.2.2.2 Apparatus
The apparatus used shall be that described in
5.3.
48 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
8.3 and 8.5 .
BRITISH STANDARD
BS 1377‑3:2018
8.2.3 Preparation of test specimen
The sample shall be prepared as in 5.4 .
8.2.4 Test procedure
8.2.4.1 A representative sample of the dried prepared material (5.4) shall be placed into the total carbon
analyzer (5.5.2 ).
8.2.4.2 The total carbon (TC) shall be measured as given in 5.5 . The total inorganic carbon (TIC) shall be
removed using the method described in 5.5.1.2 to 5.5.1.10 and analyze for total organic carbon
(TOC) as described in 5.5.2 .
NOTE
If it is known that there is no organic content then TC = TIC and the acidification stage may be omitted.
8.2.5 Calibration
8.2.5.1 The performance of the instrument shall be checked before each batch of analyzes and after
each service.
8.2.5.2
8.2.5.3
8.2.5.4
The combustion analyzer shall be calibrated using a multi-point calibration o f certified carbon
standards with different inorganic carbon and organic contents following the manufacturer’s
instructions.
The analysis of samples and check standards shall be as per manufacturer’s instructions.
Procedural blanks shall be run in duplicate. The instrumental software should automatically register
that the carbon signal for a procedural blank is below the specified calibration range and i f both o f
these duplicate values exceed this value, remedial action shall be taken to identify and correct it.
NOTE
Any chloride in the sample might corrode the analyzer.
8.2.6 Calculation
8.2.6.1 Sample
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the equation:
fraction
m 2 × 100 %
m1
finer than 2 mm =
(41)
where
m1
m2
is the initial dry mass of sample (in g);
is the mass of the sample passing the 2 mm test sieve (in g).
8.2.6.2 Carbonate content as CO
2
The carbonate content shall be calculated from total inorganic carbon = total carbon – total
organic carbon;
Or, in the absence of organic matter;
Total inorganic carbon = total carbon;
Carbonate content as CO 2 % = total inorganic carbon × 3.67.
8.2.7 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018, Clause 8
and shall contain the following information:
a)
the method of test used;
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 49
BS 1377‑3:2018
BRITISH STANDARD
the average total inorganic carbon as CO 2 (present in the soil fraction passing a 2 mm test sieve
b)
to the nearest 0.1% of the original oven dry mass of soil);
c)
the percentage by dry mass of the original sample passing the 2 mm test sieve to the
nearest 1%; and
d)
10.1 .
the information required by BS 1377‑1:2016,
8.3 Rapid titration method for determination of calcium carbonate content
8.3.1 Preparation of sample
8.3.1.1 Apparatus
8.3.1.1.1 Drying oven , controlled to a temperature range of 75 °C to 80 °C, as well as 105 °C to 110 °C.
8.3.1.1.2 Balance, readable to 0.001 g.
8.3.1.1.3 Desiccator, containing anhydrous silica gel.
8.3.1.1.4 Test sieves
8.3.1.1.5 Pestle and mortar, or a suitable mechanical crusher.
8.3.1.1.6 Sample dividers of multiple-slot type (riffle boxes) , having widths of opening of 7 mm and 15 mm.
8.3.1.1.7 Glass weighing bottle
,
2
m
m
a
n
d
4
,
a
2
p
5
p
μ
m
r
o
x
a
i
p
m
e
a
r
t
u
t
e
l
y
r
e
5
s
0
i
z
e
m
s
,
m
w
d
i
i
a
t
h
m
r
e
e
c
t
e
e
r
,
i
v
e
2
r
.
5
m
m
h
i
g
h
a
n
d
f
i
t
t
e
d
w
i
t
h
a
g
r
o
u
n
d
glass stopper.
8.3.1.1.8 Glass or plastics funnel, about 100 mm diameter.
8.3.1.2 Preparation of soil sample
8.3.1.2.1
An initial sample as described in BS 1377‑1:2016,
8.3.1.2.2
This sample shall be dried in an oven at 105 °C to 110°C and then cooled to room temperature in
8.3.1.2.3
The sample shall be sieved on a 2 mm test sieve (if appropriate, guarded by a sieve of a larger aperture).
8.3.1.2.4
All the retained particles shall be crushed to pass the 2 mm sieve and mixed thoroughly with the
8.3.1.2.5
8.3.1.2.6
8.3.1.2.7
8.3.1.2.8
1377‑1:2016,
8.3.1
8.5 shall be obtained.
,
a
n
d
o
f
t
h
e
a
p
p
r
o
p
r
i
a
t
e
s
i
z
e
s
p
e
c
i
f
i
e
d
i
n
B
S
the desiccator.
material already passing the sieve.
T
h
e
m
a
t
e
r
i
a
l
p
a
s
s
i
n
g
t
h
e
2
m
m
s
i
e
v
e
s
h
a
l
l
b
e
d
i
v
i
d
e
d
b
y
s
u
c
c
e
s
s
i
v
e
r
i
f
f
l
i
n
g
t
h
r
o
u
g
h
t
h
e
1
5
m
m
d
i
v
i
d
e
r
to produce a representative sample of approximately 50 g.
T
h
A
l
l
i
s
s
t
h
a
e
m
r
p
e
l
e
t
a
i
s
n
h
e
a
d
l
l
p
b
a
e
r
s
t
i
i
c
e
l
v
e
e
s
d
s
o
h
n
a
l
l
a
4
b
e
2
5
c
r
μ
m
u
s
h
t
e
e
d
s
t
s
t
o
i
e
p
v
e
a
s
.
s
t
h
e
4
2
5
μ
m
t
e
s
t
s
i
e
v
e
,
a
n
d
m
i
x
e
d
t
h
o
r
o
u
g
h
the material already passing the sieve.
This sample shall be used for preparing the specimens for testing (see
50 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
8.3.2.6 and also 8.4.4).
l
y
w
i
t
h
BRITISH STANDARD
BS 1377‑3:2018
8.3.2 Rapid titration test procedure
8.3.2.1 General
The requirements of BS 1377‑1, where appropriate, shall apply to this test method.
8.3.2.2 Reagents
8.3.2.2.1 All reagents shall be of recognized analytical reagent quality.
8.3.2.2.2
8.3.2.2.3
NOTE Where accurately standardized solutions are required it may be more convenient to obtain them already
standardized in concentrated form and to dilute them as necessary in accordance with the manufacturer’s
instructions.
Hydrochloric acid, [c(HCl) = approximately 1 mol/l] . Dilute 88 ml of concentrated hydrochloric acid
with distilled/de‑ionized water (BS 1377‑1:2016,
) water to make 1 l of solution.
6.1
Sodium hydroxide solution , [c(NaOH) = approximately 1 mol/l] . Dissolve about 20 g of sodium
hydroxide in 500 ml of distilled/de‑ionized water (BS 1377‑1:2016,
) and store in an airtight
plastic container. Determine the concentration (B) of this solution by preparing a 0.1 B diluted
6.1
s
o
l
u
t
i
o
n
(
p
i
p
e
t
t
e
2
5
m
l
o
f
t
h
e
c
o
n
c
e
n
t
r
a
t
e
d
s
o
l
u
t
i
o
n
i
n
t
o
6.1 ). Determine the concentration (B/10) of
a
250 ml with distilled/de‑ionized water (BS 1377‑1:2016,
the diluted solution as described in
concentrated solution.
8.3.2.2.4
2
5
0
m
l
v
o
l
u
m
e
t
r
i
c
f
l
a
s
k
a
n
d
d
i
l
u
t
e
t
o
7.7.2.4 and multiply by 10 to obtain the concentration (B) of the
Screened methyl orange indicator.
NOTE Screened methyl orange gives a more distinct end-point than the unscreened indicator but the latter may
be used if preferred. Methyl red or bromcresol green are also suitable.
8.3.2.3 Apparatus
8.3.2.3.1 250 ml tall-form beaker and watch glass cover.
8.3.2.3.2 Two 100 ml burettes reading to 0.1 ml.
8.3.2.3.3 25 ml pipette.
8.3.2.3.4 250 ml conical flask.
8.3.2.3.5 1 l volumetric flask.
8.3.2.4 Standardization of the hydrochloric acid
8.3.2.4.1
f
8.3.2.4.2
2
5
T
s
h
l
m
e
o
l
c
w
l
o
o
y
t
h
n
f
i
c
r
a
o
e
l
m
h
f
l
y
d
a
a
s
b
r
o
k
u
s
r
c
h
h
e
a
l
l
o
l
t
t
e
r
i
b
(
s
c
e
e
a
p
e
c
l
i
a
N
d
c
o
s
e
h
d
t
e
)
a
o
.
l
l
n
D
b
e
a
u
r
p
i
w
h
i
n
g
p
i
e
t
t
e
t
e
t
h
b
i
s
d
a
c
o
i
n
k
g
p
e
t
o
r
o
r
a
a
u
t
i
2
n
o
5
d
n
,
0
a
m
n
t
h
d
e
l
c
t
h
f
l
a
o
e
s
n
s
k
i
c
o
s
a
d
h
l
i
f
l
u
a
l
a
m
l
b
s
k
.
h
e
y
d
r
o
r
o
t
a
x
i
t
e
d
d
e
c
s
o
o
n
l
s
u
t
i
t
a
o
n
n
t
l
a
y
d
w
d
i
e
d
t
h
o
n
e
hand while the stopcock on the burette is controlled with the other.
NOTE The burette that contained sodium hydroxide should be cleaned soon after use by thoroughly rinsing with
water. The burette can be damaged and the tap seize if this is not done.
8.3.2.4.3 The sodium hydroxide shall be added until the acid is neutralized as indicated by the colour change.
8.3.2.4.4 The volume of sodium hydroxide used shall be recorded, V .
8.3.2.4.5 8.3.2.4.1 to 8.3.2.4.4 shall be repeated using two more 25 ml aliquots of acid solution. The volumes
1
of sodium hydroxide used for each titration shall not differ by more than 0.1 ml.
8.3.2.4.6
The following shall be calculated; the mean volume of sodium hydroxide used V1 (in ml) and the
concentration (H) of the hydrochloric acid solution (in mol/l), from the following equation:
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 51
BS 1377‑3:2018
BRITISH STANDARD
H=
V1 B
(42)
25
where
B
is the concentration of the sodium hydroxide solution (in mol/l).
8.3.2.5 Preparation of the test sample
8.3.2.5.1 The test sample shall be prepared in accordance with 8.3.1.2 , taking representative portions
containing a little over 5 g of oven‑dry soil.
8.3.2.5.2
This proportion shall be dried in the oven at 105 °C to 110 °C . The specimen shall be deemed to
be dry when the difference in successive weighings at intervals of 4 h do not exceed 0.1% of the
specimen mass.
8.3.2.5.3
8.3.2.5.4
The specimen shall be allowed to cool to room temperature in the desiccator.
Approximately 5 g of dry soil shall be weighed as the test specimen and its mass (m) recorded to the
nearest 0.001 g.
8.3.2.6 Analysis of test specimen
8.3.2.6.1 The weighed specimen shall be placed into the 250 ml tall‑form beaker.
8.3.2.6.2 100 ml of the hydrochloric acid solution shall be added slowly from the burette.
8.3.2.6.3 The beaker shall be covered with the watch glass and allowed to stand for 1 h, stirring occasionally.
8.3.2.6.4
f
f
W
h
w
8.3.2.6.5
S
i
i
e
n
t
h
x
d
t
h
t
h
r
o
e
p
e
s
p
s
i
o
p
o
f
i
l
e
h
a
t
t
e
t
h
e
s
a
i
s
n
n
e
d
d
i
t
t
l
e
t
r
a
c
a
d
n
t
o
a
s
r
t
e
f
s
e
o
r
l
r
t
h
t
o
u
t
i
a
o
e
f
i
c
n
o
n
n
a
i
l
c
s
a
t
i
l
r
f
l
r
a
i
s
n
g
,
2
5
m
l
o
t
h
e
s
u
p
e
r
n
a
t
a
n
t
l
i
q
u
i
d
s
h
a
l
l
b
e
r
e
m
o
v
e
d
k
.
8.3.2.4 until the same colour change as was observed
8.3.2.4.3 ) occurs. The volume (V ) of sodium hydroxide solution
s
h
a
l
l
b
e
a
d
d
e
d
t
o
t
h
e
l
i
q
u
i
d
i
n
t
h
e
c
o
n
i
c
a
l
f
l
a
s
k
a
n
d
t
i
t
r
a
t
e
d
w
i
t
h
the sodium hydroxide solution as described in
in the standardization procedure (
2
used shall be recorded, to the nearest 0.1 ml.
8.3.2.7 Calculations
8.3.2.7.1 Sample
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the equation:
f
r
a
c
t
i
o
n
f
i
n
e
r
t
h
a
n
2
m
m
=
m 2 × 100
m1
(43)
where
m
m
1
is the initial dry mass of sample (in g);
2
is the mass of the sample passing the 2 mm test sieve (in g).
8.3.2.7.2 Carbonate content
The carbonate content of the soil, as a percentage of CO 2 , shall be calculated from the equation:
carbonate (as CO 2 ) =
8 . 8( 25 H − BV2 )
m
where
H
B
is the concentration of the hydrochloric acid (in mol/l);
is the concentration of the sodium hydroxide solution (in mol/l);
52 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
(44)
BRITISH STANDARD
BS 1377‑3:2018
m
is the mass of the soil specimen (in g);
V2
is the volume of sodium hydroxide used (in ml).
8.3.2.8 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018 and shall
contain the following information:
a)
the method of test used;
b)
the percentage carbonates in the soil sample, expressed as CO 2
c)
the percentage by dry masss of the original sample passing the 2 mm test sieve to the
,
t
o
t
w
o
s
i
g
n
i
f
i
c
a
n
t
f
i
g
u
r
e
s
;
nearest 1%; and
d)
the information required by BS 1377‑1:2016,
10.1 .
8.4 Gravimetric method for determination of calcium carbonate content
8.4.1 General
The requirements of BS 1377‑1, where appropriate, shall apply to this test method.
8.4.2 Apparatus
8.4.2.1 Apparatus shall be as described in BS 1881‑124:2015, 6.3 .
8.4.2.2 Balance, readable to 0.0001 g.
8.4.3 Reagents
The reagents shall be as described in BS 1881‑124:2015, 6.2 .
8.4.4 Preparation of test specimen
8.4.4.1 From the sample prepared as described in 8.3.1 a representative test specimen of the required mass
shall be taken.
8.4.4.2
NOTE As an approximate guide, the amount of soil required will range from about 0.2 g for a pure limestone or
chalk to 1 g for a relatively non-calcareous soil. If in doubt the appropriate quantity should be ascertained from
preliminary trial tests.
The specimen shall be dried in the oven at 105 °C to 110 °C. The specimen shall be deemed to
be dry when the difference in successive weighings at intervals of 4 h do not exceed 0.1% of the
specimen mass.
8.4.4.3 The specimen shall be allowed to cool to room temperature in the desiccator.
8.4.4.4 The mass of the specimen shall be determined to 0.0001 g.
8.4.5 Analysis of test specimen and calculations
The procedure followed shall be as described in BS 1881‑124:2015, 6.7 .
8.4.6 Calculation
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the equation:
f
r
m2
a
c
t
i
o
n
f
i
n
e
r
t
h
a
n
2
m
m
=
m1
× 100
(45)
where
m1
is the initial dry mass of sample (in g);
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 53
BS 1377‑3:2018
BRITISH STANDARD
m2
is the mass of the sample passing the 2 mm test sieve (in g).
8.4.7 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018,
shall contain the following information:
9
a)
the method of test used;
b)
the percentage carbonate in the soil sample, expressed as CO 2 ;
c)
the percentage of dry mass of the original sample passing a 2 mm test sieve; and
d)
the information required by BS 1377‑1:1990,
8.4 and
10.1 .
Determination of the chloride content
9.1 General
9.1.1 Principle
This clause describes the preparation of a sample for the determination of the chloride content and
the analysis of the prepared sample. Analysis for water soluble and groundwater soluble chloride
of the test material might be done using ion chromatography, which is preferred and water soluble,
groundwater soluble chloride acid soluble chloride salt content may be done using test procedures
based on Volhard’s method.
NOTE 1 The principle can also be used for determining chlorides in ground water for which Mohr’s method is more
suitable than Volhard’s method, see BRE Report 279 [3].
NOTE 2 Alternative methods based on potentiometric titration may be used as found in BS EN 1744-1.
For the determination of water‑soluble chlorides (see
9.2 ) the chlorides are extracted from a dry soil
sample by solution in a mass of water equal to twice that of the sample. Results are expressed as the
chloride ion content.
A qualitative test for checking for the presence of chlorides is included, which if negative obviates the
need for the quantitative analysis.
For the determination of acid‑soluble chlorides (see
9.3 ), which includes chlorides not extracted by
water, chlorides are extracted from a dry soil sample with dilute nitric acid.
Results are expressed as the chloride content.
9.1.2 Applications
The water‑extract chloride content is applicable only to materials in which the chloride content
derives directly from recent contact with, or immersion in, saline water.
NOTE The principle can also be used for determining chlorides in ground water for which Mohr’s method is more
suitable, see BRE Report 279 [3].
The acid‑extract method is applicable to the determination of the chloride content of soils from
desert areas or where the origin of the chlorides is uncertain.
9.2 Determination of water-soluble chloride content
9.2.1 General
The requirements of BS 1377‑1, where appropriate, shall apply to this test method.
9.2.2 Apparatus
9.2.2.1 Balance, readable to 1 g.
54 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
9.2.2.2
9.2.2.3
9.2.2.4
9.2.2.5
9.2.2.6
9.2.2.7
9.2.2.8
9.2.2.9
9.2.2.10
9.2.2.11
9.2.2.12
9.2.2.13
9.2.2.14
9.2.2.15
9.2.2.16
9.2.2.17
9.2.2.18
9.2.2.19
BS 1377‑3:2018
Balance, readable to 0.001 g.
1 l volumetric flask.
10 ml graduated glass measuring cylinder.
500 ml graduated glass measuring cylinder.
100 ml pipette.
25 ml pipette.
Two 50 ml burettes.
Stoppered conical flasks, 250 ml capacity. (At least four.)
Wash bottle, preferably made of plastics, containing distilled/de‑ionized water (BS 1377‑1:2016, 6.1 ).
Amber-coloured glass reagent bottle.
Wide mouth screw-capped plastics or metal bottle, of 2 l capacity. The cap shall be watertight
when closed.
Mechanical shaking apparatus, capable of keeping 500 g of soil and 1 000 ml of water contained in the
bottles in continuous suspension.
NOTE A device which rotates the containers end over end at 30 r/min to 60 r/min is satisfactory. Shaking
machines giving a vibrating motion are also suitable.
Drying oven , capable of being controlled to maintain temperatures of (105 ±5) °C and (150 ±5) °C,
conforming to BS 1377‑1:2016,
4.2.2.1 .
Desiccator containing anhydrous silica gel.
Filter funnel, of approximately 100 mm diameter.
Filter papers, of a diameter appropriate to the size of the funnel: medium grade (e.g. Whatman No.
40 7) ) and fine grade (e.g. Whatman No. 42 7) ).
Test sieve, of 2 mm aperture size, with receiver.
Sample dividers of multiple-slot type (riffle boxes), conforming to BS 1377‑1:2016, having widths of
opening of 7 mm and 15 mm.
9.2.2.20 Pestle and mortar, or a suitable mechanical crusher.
9.2.2.21 500 ml volumetric flask.
9.2.2.22 Two beakers, of about 250 ml capacity.
9.2.3 Preparation of test specimen
9.2.3.1 A specimen for analysis shall be prepared from the laboratory sample as given in 9.2.3.2 .
9.2.3.2 An initial sample shall be obtained, as described in 9.2.3.3 to 9.2.3.8 , and of the approximate size
specified in BS 1377-1:2016, Table 5.
9.2.3.3
9.2.3.4
This sample shall be dried in an oven at 105 °C to 110 °C, and allowed to cool to room temperature in
the desiccator containing dry desiccant.
The sample shall be sieved on a 2 mm test sieve (guarded by a test sieve of a larger aperture if
appropriate) and the retained particles other than stones shall be crushed to pass through the
2 mm test sieve.
7
Whatman is a trademark of GE Healthcare. This information is given for the convenience of users of this document and does not constitute
an endorsement by the British Standards Institution of the named product. Equivalent products may be used if they can be shown to lead to
the same results.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 55
BS 1377‑3:2018
9.2.3.5
T
h
9.2.3.7
e
s
t
o
n
e
s
s
h
a
l
l
b
e
r
e
j
e
c
t
e
d
,
e
n
s
u
r
i
n
g
t
h
a
t
n
o
f
i
n
e
m
a
t
e
r
i
a
l
a
d
h
e
r
e
s
t
o
t
h
e
m
,
e
.
g
.
b
y
b
r
u
s
h
i
n
g
.
T
h
e
mass m 2 shall be recorded in g of sample passing the 2 mm test sieve to the nearest 0.1%. Throughout
t
h
9.2.3.6
BRITISH STANDARD
T
e
h
s
e
e
a
m
n
a
d
t
e
s
r
i
u
a
b
l
s
p
e
a
q
s
u
s
i
e
n
n
t
g
o
t
h
p
e
e
r
2
a
t
i
m
o
n
m
s
t
h
t
e
s
t
e
s
r
i
e
e
s
h
v
e
a
s
l
h
l
b
a
l
e
l
n
b
o
e
l
d
i
o
v
s
i
s
d
o
e
f
d
f
i
b
n
e
y
s
s
.
u
c
c
e
s
s
i
v
e
r
i
f
f
l
i
n
g
t
h
r
o
u
g
h
t
h
e
1
m
m
divider to produce the following:
a)
a test specimen of about 500 g; and
b)
a specimen of about 50 g for a qualitative check test to determine whether chlorides are present.
The specimens shall be dried in the oven at 105 °C to 110 °C. The specimens shall be deemed to be
dry when the differences in successive weighings carried out at intervals of 4 h, do not exceed 0.1% of
the original mass of the sample.
9.2.3.8
The specimens shall be allowed to cool to room temperature in the desiccator containing
dry desiccant.
9.2.4 Qualitative check for chlorides
9.2.4.1 Reagents
9.2.4.1.1 All reagents shall be of recognized analytical reagent quality.
NOTE Where accurately standardized solutions are required it may be more convenient to obtain them already
standardized in concentrated form and to dilute them as necessary in accordance with the manufacturer’s
instructions.
9.2.4.1.2
Silver nitrate solution [c(AgNO 3 ) = 0.100 mol/l] . Dry about 20 g of silver nitrate at not more than 150 °C
for 1 h to 2 h and allow to cool in the desiccator. Weigh out 16.987 g of the dried silver nitrate, dissolve
6.1
in distilled/de‑ionized water (BS 1377‑1:2016,
)
a
n
d
d
i
l
u
t
e
t
o
1
l
i
n
a
v
o
l
u
m
e
t
r
i
c
f
l
a
s
k
.
S
t
o
r
e
t
h
e
solution in the amber‑coloured glass reagent bottle and protect from prolonged exposure to sunlight.
9.2.4.2 Procedure
9.2.4.2.1
9.2.4.2.2
9.2.4.2.3
9.2.4.2.4
T
5
h
0
e
p
g
r
e
c
h
s
e
e
c
n
k
c
s
e
p
o
e
f
c
c
i
h
m
l
e
o
r
n
i
s
d
h
e
a
s
l
i
l
n
b
t
h
e
p
e
l
a
s
o
c
e
i
l
d
s
i
h
a
n
l
a
l
b
5
e
0
v
e
0
r
m
i
l
f
i
c
e
o
d
n
a
i
c
s
a
d
l
e
f
l
s
a
c
s
r
b
e
d
6.1 ).
k
distilled/de‑ionized water shall be added (BS 1377‑1:2016,
i
a
n
d
i
n
t
o
9.2.4.2.2 to 9.2.4.2.5 .
i
t
a
n
a
p
p
r
o
x
i
m
a
t
e
l
y
e
q
u
a
l
m
a
s
s
o
f
The contents shall be agitated intermittently for 4 h, allowed to settle and some of the supernatant
solution poured into a beaker.
A
b
o
u
t
2
5
m
l
o
f
c
l
e
a
r
s
o
l
u
t
i
o
n
s
h
a
l
l
b
e
o
b
t
a
i
n
e
d
b
y
f
i
l
t
e
r
i
n
g
,
i
f
n
e
c
e
s
s
a
r
y
,
t
h
r
o
u
g
h
a
m
e
d
i
u
m
g
r
a
d
e
f
i
l
t
e
r
paper, e.g. Whatman No. 40® .
8)
9.2.4.2.5
T
h
e
l
i
q
u
i
d
s
h
a
l
l
b
e
a
c
i
d
i
f
i
e
d
w
i
t
h
n
i
t
r
i
c
a
c
i
d
,
a
d
d
a
b
o
u
t
f
i
v
e
d
r
o
p
s
o
f
t
h
e
s
i
l
v
e
r
n
i
t
r
a
t
e
s
o
l
u
t
i
o
n
s
h
a
l
l
b
e
added and allowed to stand for 10 min.
NOTE If no turbidity is apparent after this time the soluble chloride ion content of the soil is not likely to cause
harm to construction materials and the quantitative test for chloride content is not necessary.
8
Whatman is a trademark of GE Healthcare. This information is given for the convenience of users of this document and does not constitute
an endorsement by the British Standards Institution of the named product. Equivalent products may be used if they can be shown to lead to
the same results.
56 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
9.2.5 Quantitative tests for water-soluble chloride content
9.2.5.1 Preparation of water-soluble chloride extract
9.2.5.1.1 The water‑soluble chloride extract shall be obtained from each test portion as described in 9.2.5.1.2
to 9.2.5.1.8 .
9.2.5.1.2
A clean and dry screw‑capped bottle shall be weighed to 1 g, and record its mass.
9.2.5.1.3
The test specimen shall be placed in the bottle and weigh the bottle and contents weighed to 1 g.
9.2.5.1.4
The mass of soil shall be calculated by difference m (in g).
9.2.5.1.5
To the bottle a mass of distilled/de‑ionized water (BS 1377‑1:2016,
9.2.5.1.6
The watertight caps shall be fastened securely.
9.2.5.1.7
The bottle shall be secured to the shaking apparatus and shaken for at least 16 h.
twice the mass of the test specimen.
NOTE
9.2.5.1.8
6.1 ) m
T
l
h
e
e
a
t
h
s
r
o
shall be added, equal to
When convenient the soil can be left shaking overnight.
s
t
w
u
1
u
s
0
g
p
e
0
h
a
n
m
f
i
s
l
n
i
o
o
e
n
f
-
s
c
g
l
r
h
e
a
a
a
d
l
r
e
l
f
i
b
l
f
i
e
t
r
l
f
i
a
t
e
l
t
e
r
p
t
e
h
a
r
a
p
e
s
e
d
b
t
h
e
e
r
o
n
u
c
g
h
o
l
l
e
a
c
m
t
e
d
e
.
d
I
f
i
u
m
t
h
e
-
g
f
i
r
a
l
d
t
r
a
e
f
i
t
e
i
l
s
t
e
n
r
o
t
p
c
a
p
o
e
m
r
p
i
l
n
e
t
o
t
e
l
a
y
c
c
l
e
l
e
a
a
r
,
n
i
t
b
s
e
h
a
a
k
e
l
l
r
b
u
e
n
f
i
l
t
i
t
e
l
r
a
e
t
d
r
.
NOTE 1 If the solids settle quickly and the supernatant liquid is clear it can be carefully poured off instead
of filtering.
NOTE 2 A portion of the same 2:1 water-soil extract as prepared for sulfate analysis may be used.
9.2.6 Ion Chromatography (IC)
The method given in 7.4 shall be used including the calibration for chloride ions.
See 7.4.8 for calculations.
9.2.7 Volhard’s method
9.2.7.1 Reagents
9.2.7.1.1 All reagents shall be of recognized analytical reagent quality.
NOTE Where accurately standardized solutions are required it may be more convenient to obtain them already
standardized in concentrated form and to dilute them as necessary in accordance with the manufacturer’s
instructions.
9.2.7.1.2
Silver nitrate solution [c(AgNO 3 ) = 0.100 mol/l] . Dry about 20 g of silver nitrate at not more than 150 °C
for 1 h to 2 h and allow to cool in the desiccator. Weigh out 16.987 g of the dried silver nitrate, dissolve
in distilled/de‑ionized water (BS 1377‑1:2016,
6.1
)
a
n
d
d
i
l
u
t
e
t
o
1
l
i
n
a
v
o
l
u
m
e
t
r
i
c
f
l
a
s
k
.
S
t
o
r
e
t
h
e
solution in the amber‑coloured glass reagent bottle and protect from prolonged exposure to sunlight.
9.2.7.1.3
Thiocyanate solution , [c(NH 4SCN) or c(KSCN) = approximately 0.1 mol/l] .
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 57
BS 1377‑3:2018
9.2.7.1.4
9.2.7.1.5
9.2.7.1.6
9.2.7.1.7
BRITISH STANDARD
Potassium thiocyanate, 10.5 g or ammonium thiocyanate, 8.5 g dissolved in distilled/de‑ionized water
(BS 1377‑1:2016,
) water to 1 l in a volumetric flask.
6.1
Nitric acid solution , [c(HNO 3 ) = approximately 6 mol/l] . Dilute 100 ml of nitric acid (70% HNO 3 1.42
g/ml) with distilled/de‑ionized water (BS 1377‑1:2016,
) to 250 ml and boil the diluted acid until
it is colourless.
6.1
3,5,5-Trimethylhexan-1-ol.
Ferric alum indicator solution . Add 60 g of water to 75 g of ammonium ferric sulfate, warm to dissolve,
and add 10 ml of nitric acid (
). Allow to cool and store in a glass bottle.
9.2.7.1.5
9.2.7.2 Apparatus
For apparatus see
9.2.2 .
9.2.8 Procedure
9.2.8.1 Standardization of thiocyanate solution
9.2.8.1.1 The concentration of the thiocyanate solution shall be determined as given in 9.2.7.1.3 .
9.2.8.1.2
9.2.8.1.3
25 ml o f the silver nitrate solution shall be trans ferred into a 250 ml conical flask, using a pipette, and
add 5 ml of the nitric acid solution and 1 ml of ferric alum indicator solution.
The thiocyanate solution shall be added from a burette until the first permanent colour change occurs,
that is from colourless to pink.
9.2.8.1.4
The volume of thiocyanate solution added shall be recorded in V1 (in ml).
9.2.8.1.5
The concentration C (in mol/l) of the solution shall be calculated from the following equation:
C = 2.5
V1
(46)
9.2.8.2 Analysis of extract
9.2.8.2.1
9.2.8.2.2
9.2.8.2.3
9.2.8.2.4
9.2.8.2.5
Each water extract sample shall be analysed as described in
9.2.8.2.2 to 9.2.8.2.8.
100 ml o f the filtered extract shall be taken by means o f the pipette and trans ferred to the 250 ml
conical flask.
5 ml o f the nitric acid solution shall be added to the flask followed by silver nitrate solution from a
burette until all the chloride has been precipitated, and then a little excess silver nitrate shall be added.
The total volume V2 (in ml) of silver nitrate solution added shall be recorded.
2 ml o f 3,5,5-trimethylhexan-1-ol, shall be added, the stopper fitted and the flask shaken vigorously to
coagulate the precipitate.
58 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
9.2.8.2.6
9.2.8.2.7
BS 1377‑3:2018
The stopper shall be carefully loosened, avoiding loss of solution, rinsed with distilled/de‑ionized
6.1 ), and the washings in the solution collected.
water (BS 1377‑1:2016,
5 ml of the ferric alum indicator solution shall be added, followed by the standardized thiocyanate
s
o
l
u
t
i
o
f
n
r
o
m
a
b
u
r
e
t
t
e
u
n
t
i
l
t
h
e
f
i
r
s
t
p
e
r
m
a
n
e
n
t
c
o
l
o
u
r
c
h
a
n
g
e
o
c
c
u
r
s
9.2.8.2.8
f
9.2.8.1 .
,
t
h
and is the same colour as was used for the standardization described in
a
t
i
s
r
o
m
c
o
l
o
u
r
l
e
s
s
t
o
r
e
d
,
The volume V3 (in ml) of thiocyanate solution shall be added.
9.2.9 Calculations
9.2.9.1 Soil samples
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the equation:
f
r
a
c
t
i
o
n
f
i
n
e
r
t
h
a
n
2
m
m
=
m 2 × 100
m1
(47)
where
m
m
1
is the initial dry mass of sample (in g);
2
is the mass of the sample passing the 2 mm test sieve (in g).
9.2.9.2 Ion Chromatography
The value of water‑soluble chloride from the chromatography method shall be calculated:
The dilution factor (DF) shall be calculated using equation (48) and is the ratio of the volume of the
i
n
i
t
i
a
l
c
o
n
c
e
n
t
r
a
t
i
o
n
s
o
l
u
t
i
o
n
t
o
t
h
e
v
o
l
u
m
e
o
f
t
h
e
f
i
n
a
l
,
d
i
l
u
t
e
d
V2
V1
DF =
s
o
l
u
t
i
o
n
.
(48)
where
V
V
ρ
c
=
ρ
i
×
D
1
is the volume of the undiluted solution;
2
is the volume of the diluted solution that is tested.
F
(
4
9
)
where
ρ
ρ
c
is concentration of the initial sample;
i
is the measured concentration of the diluted sample.
The dilution factor = 1 if not diluted.
T
h
e
f
i
n
a
l
c
o
n
c
e
n
t
r
a
t
i
o
n
,
ρ
f
,
i
s
ρ
f
=
ρ
c
–
ρ
b
(50)
where
ρ
b
is the concentration of the blank solution.
The blank solution shall not be diluted, but if it is, this shall be corrected for using the dilution factor.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 59
BS 1377‑3:2018
BRITISH STANDARD
9.2.9.3 Volhard’s method
The amount of chloride ions present in each water extract shall be calculated as a percentage by dry
mass of soil, from the equation:
Chloride ion content = 0.007092 (V2 – 10 CV3 )
(51)
where
V2
is the volume of the silver nitrate solution added (in ml);
V3
is the volume of the diluted solution that is tested;
C
is the concentration of the standardized thiocyanate solution (in mol/l)
If more than one specimen has been tested, and if the individual results differ by not more than 0.1%
of chloride ion content, the mean result shall be calculated. If they differ by more than 0.1%, the test
shall be repeated starting with two new test specimens.
9.2.10 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018 and shall
contain the following information:
a)
the method of test used;
b)
the method of chemical analysis method;
c)
the percentage by dry mass of the original sample passing the 2 mm test sieve to the nearest 1%;
d)
the percentage of chloride ions in the soil sample, to the nearest 0.01%;
e)
the water to soil ratio used for preparing the soluble extract; and
f)
the information required by BS 1377‑1:2016,
10.1 .
9.3 Determination of acid-soluble chloride content
9.3.1 Reagents
The reagents required are the same as those listed in
9.2.7.1.
9.3.2 Apparatus
9.3.2.1 Balance, readable to 1 g.
9.3.2.2 Balance, readable to 0.001 g.
9.3.2.3 1 l volumetric flask.
9.3.2.4 10 ml graduated glass measuring cylinder.
9.3.2.5 50 ml graduated glass measuring cylinder.
9.3.2.6 10 ml graduated glass measuring cylinder.
9.3.2.7 1 5 ml pipette.
9.3.2.8 500 ml beaker.
9.3.2.9 Two 50 ml burettes.
9.3.2.10 Stoppered conical flasks, 250 ml capacity. (At least two.)
9.3.2.11 Filter funnel, of approximately 100 mm diameter.
60 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
9.3.2.12
BS 1377‑3:2018
Filter papers, of a diameter appropriate to the size of the funnel: coarse grade (e.g. Whatman
No. 541® 9) ).
9.3.2.13 Test sieve f
9.3.2.14 Pestle and mortar, or a suitable mechanical crusher.
9.3.2.15 Sample dividers of multiple-slot type (riffle boxes).
9.3.3 Test procedure
9.3.3.1 General
,
o
1
5
0
μ
m
a
p
e
r
t
u
r
e
s
i
z
e
w
i
t
h
r
e
c
e
i
v
e
r
.
9.2.7.1 shall
For the standardization of potassium thiocyanate solution, the procedure described in
be followed.
9.3.3.2 Preparation of test specimen
9.3.3.2.1
9.3.3.2.2
A specimen for analysis from the laboratory sample shall be prepared as described in
to
9.3.3.2.7 .
9.3.3.2.2
An initial sample shall be obtained as described in
9.3.3.2.3
The sample shall be dried in an oven between 105 °C to 110 °C, and cooled to room temperature in
9.3.3.2.4
9.3.3.2.5
9.3.3.2.6
9.3.3.2.7
9.2.2
BS 1377‑1:2016, Table 5.
a
n
d
o
f
t
h
e
a
p
p
r
o
x
i
m
a
t
e
s
i
z
e
s
p
e
c
i
f
i
e
d
i
n
the desiccator.
T
h
e
s
a
m
p
l
e
s
h
a
l
l
b
e
s
i
e
v
e
d
o
n
a
1
5
0
μ
m
t
e
s
t
s
i
e
v
e
(
i
f
a
p
p
r
o
p
r
i
a
t
e
,
g
u
a
r
d
e
d
b
y
a
s
i
e
v
e
o
f
l
a
r
g
e
r
a
p
e
r
t
u
r
e
)
.
Crush all retained particles to pass the 150 mm sieve and mixed thoroughly with the material already
passing the sieve.
T
h
e
m
a
t
e
r
i
a
l
s
h
a
l
l
b
e
s
i
e
v
e
d
b
y
s
u
c
c
e
s
s
i
v
e
r
i
f
f
l
i
n
g
t
o
p
r
o
d
u
c
e
t
e
s
t
s
p
e
c
i
m
e
n
s
e
a
c
h
o
f
a
b
o
u
t
1
0
g
.
The test specimens shall be dried in the oven at 105 °C to 110 °C, and allowed to cool in the desiccator.
9.3.3.3 Preparation of acid-soluble chloride extract
9.3.3.3.1
The acid‑soluble chloride extract shall be obtained from each test portion as described in
9.3.3.3.2
(5 ±0.005) g of the test portion shall be weighed out and placed it in a 500 ml beaker.
9.3.3.3.3
9.3.3.3.4
9
to
9.3.3.3.11 .
50 ml of distilled/de‑ionized water (BS 1377‑1:2016,
followed by 15 ml of nitric acid.
9.3.3.3.2
6.1 ) shall be added to disperse the particles,
The beaker with sample and water shall be heated to near boiling point and kept warm for
10 min to 15 min.
Whatman is a trademark of GE Healthcare. This information is given for the convenience of users of this document and does not constitute
an endorsement by the British Standards Institution of the named product. Equivalent products may be used if they can be shown to lead to
the same results.
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BS 1377‑3:2018
9.3.3.3.5
BRITISH STANDARD
The contents o f the beaker shall be filtered through a coarse-grade filter paper into a conical flask, and
the filter paper washed with hot water and the washings collected with the filtrate and allowed to cool.
NOTE
Some cloudiness in the filtrate is acceptable.
9.3.3.3.6
Silver nitrate solution from a burette shall be added until all the chloride has been precipitated, then a
9.3.3.3.7
The total volume shall be recorded V2 (in ml) of silver nitrate solution added.
9.3.3.3.8
9.3.3.3.9
9.3.3.3.10
little excess silver nitrate added.
2 ml o f 3,5,5-trimethylhexan-1-ol shall be added, a stopper fitted to the flask and the flask vigorously
shaken to coagulate the precipitate.
The stopper shall be carefully loosened, avoiding loss of solution, rinsed with distilled/de‑ionized
water (BS 1377‑1:2016,
6.1 ), and the washings in the solution collected.
5 ml of the ferric alum indicator solution shall be added, followed by the standardized potassium
thiocyanate solution from a burette until the first permanent colour change occurs, that is from
.
colourless to red, and is the same colour as was used for the standardization described in
9.3.3.3.11
9.2.7.1
The volume V3 (in ml) of thiocyanate solution added shall be recorded.
9.3.4 Calculations
9.3.4.1 Sample
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the equation:
fraction
finer than 2 mm =
m 2 × 100
m1
(52)
where
m
m
1
is the initial dry mass of sample (in g);
2
is the mass of the sample passing the 2 mm test sieve (in g).
9.3.4.2 Chloride content
Calculate the chloride content of the soil as a percentage by dry mass of soil from the equation:
Chloride content = 0.07092 (V2 – 10 CV3 )
(53)
where
V
V
C
2
is the volume of the silver nitrate solution added (in ml);
3
is the volume of standardized thiocyanate solution added (in ml);
is the concentration of the standardized thiocyanate solution (in mol/l).
If more than one specimen has been tested, and if the results differ by no more than 0.1% of chloride
content, the mean result shall be calculated. If they differ by more than 0.1%, the test shall be
repeated starting with two new test specimens.
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BRITISH STANDARD
BS 1377‑3:2018
9.3.5 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018, 9.3 and
shall contain the following information:
a)
the method of test used;
b)
the percentage of chlorides in the soil sample, to the nearest 0.01%;
c)
the percentage of dry mass of the original sample passing a 2 mm test sieve to the nearest 1%;
d)
the method used, i.e. the acid extraction method; and
e)
the information required by BS 1377‑1:2016, 10.1 .
10 Determination of magnesium — water-soluble magnesium in 2:1 extract
10.1 Principle
A sample prepared as described in 7.2.3 is mixed with distilled/de‑ionized water (BS 1377‑1:2016,
6.1 ) water, preferably high purity water, in a 2:1 water: sample mass ratio, shaken overnight and
f
10.4 and is
reported in mg/l.
f
i
l
t
e
r
e
d
.
T
h
e
m
a
g
n
e
s
i
u
m
c
o
n
t
e
n
t
o
t
h
e
w
a
t
e
r
e
x
t
r
a
c
t
i
s
d
e
t
e
r
m
i
n
e
d
b
y
t
h
e
m
e
t
h
o
d
i
n
NOTE 1 The sample preparation in 10.2 and the test method in 10.4 may also be used to determine the magnesium
content of samples of groundwater and surface water provided they have been filtered using the method for the
assessment of sulfate groundwater content in 7.8 or an equivalent method.
NOTE 2 Water-soluble magnesium is often determined as part of the process of assessing the risk posed by sulfate
to concrete (BRE, 2005 [1]), so the water-soluble magnesium may usefully be determined on the same extract as
the water-soluble sulfate, ensuring that the results are directly comparable. The method of sample preparation and
preparation of the 2:1 water to solid by mass extract, therefore, follows that for water-soluble sulfate.
10.2 Sample preparation
10.2.1 Apparatus
The apparatus listed in 7.2.3.1 shall be used.
10.2.2 Preparation of sample
The soil or rock sample shall be prepared as described in 7.3.2 .
10.3 Preparation of 2:1 water-soluble extract
10.3.1 Apparatus
The apparatus in 7.3.2.3.2 to 7.3.2.3.8 shall be used.
10.3.2 Preparation of extract
The water‑soluble extract shall be prepared as described for water‑soluble sulfate in 7.3.3 .
10.4 Determination of magnesium in solution
10.4.1
ICP‑AES or a similar method shall be used to determine the concentration of magnesium in solution.
The method described in 7.5 but for magnesium shall be followed.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 63
BS 1377‑3:2018
BRITISH STANDARD
10.5 Calculations
10.5.1 Sample
The percentage of the original soil sample passing the 2 mm test sieve shall be calculated from
the equation:
f
r
a
c
t
i
o
n
f
i
n
e
r
t
h
a
n
2
m
m
m 2 × 100
m1
=
(54)
where
m1
m2
is the initial dry mass of sample (in g);
is the mass of the sample passing the 2 mm test sieve (in g).
10.5.2 Magnesium content
The results from the ICP‑AES or similar shall be calculated from the following.
Corrections for dilutions:
ρ
c
=
ρ
i
×
d
i
l
u
t
i
o
n
f
a
c
t
o
r
(
s
e
e
7.4.8)
(55)
The dilution factor = 1 if not diluted.
T
h
e
f
i
n
a
l
c
o
n
c
e
n
t
r
a
t
i
o
n
,
ρ
f
,
i
s
ρ
f
=
ρ
c
–
ρ
b
(56)
where
ρ
ρ
b
f
is the concentration of the blank solution;
the magnesium content in mg/l.
If more than one test has been carried out on a single prepared test sample and the results differ by
not more than 20 mg/l (Mg), the mean result shall be calculated. If they differ more than 20 mg/l the
test shall be repeated with two new analytical portions of the soil.
The result as m 3 (mg/l Mg) shall be calculated to the nearest 10 mg/l. If dilution of the sample is
necessary for analysis it shall be reported. Also, the magnesium content of the blank solution shall be
determined and the sample test result correct.
10.6 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018, Clause 10
and shall contain the following information:
a)
the method of test used;
b)
the water‑soluble magnesium content to the nearest 10 mg/l;
c)
the percentage by dry mass of the original sample passing a 2 mm test sieve, to the nearest 1%;
d)
the pH of the water extract to the nearest 0.1 pH unit; and
e)
the information required by BS 1377‑1:2016, 10.1 .
11 Determination of total dissolved solids
11.1 General
This clause describes a method for determining the total amount of dissolved solids in a sample
of water, e.g. groundwater. The requirements of BS 1377‑1, where appropriate, shall apply to this
test method.
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BRITISH STANDARD
BS 1377‑3:2018
11.2 Apparatus
11.2.1
11.2.2
11.2.3
11.2.4
11.2.5
11.2.6
11.2.7
11.2.8
11.2.9
11.2.10
11.2.11
11.2.12
Buchner funnel, of about 100 mm diameter.
Vacuum filtration flask, of about 500 ml capacity, to take the funnel.
Source of vacuum, and vacuum tubing .
Filter papers, to fit the funnels, e.g. Whatman No. 40® 10) .
Evaporating dish, which can be accommodated on the balance (11.2.9 ).
Drying oven , capable of maintaining a temperature of 180 °C to within ±10 °C.
Desiccator, containing anhydrous silica gel.
Volumetric flask.
NOTE
The size of the flask depends on the amount of water required for test (see
1 1 . 3. 2
).
Balance, readable to 0.5 mg.
Electric hotplate, or Bunsen burner and tripod.
Shallow container, suitable for use as a boiling water bath.
Wash-bottle, preferably made of plastics, containing distilled/de‑ionized water (BS 1377‑1:2016, 6.1 ).
11.3 Test procedure
11.3.1
The sample o f water shall be filtered to remove any suspended solids, using the Buchner
funnel and flask.
11.3.2
A known volume V (in ml) o f filtered water (su fficient to yield between 2.5 mg and 1.000 mg o f
11.3.3
An evaporating dish shall be heated in the oven at (180 ±10) °C for 30 min, allowed to cool in the
dissolved solids) shall be collected and poured into the volumetric flask.
desiccator containing dry self‑indicating silica gel or similar desiccant, and its mass m 1 determined
to 0.0005 g.
11.3.4
A portion of the water sample shall be poured into the evaporating dish and evaporated on the boiling
water bath. This shall be done in a clean atmosphere to prevent contamination by airborne solids.
11.3.5
Further portions of the water sample shall be added to the dish as evaporation proceeds. When the
11.3.6
The water shall be allowed to evaporate to ensure the evaporating dish is dry. The outside of the dish
11.3.7
11.3.8
flask is empty it shall be rinsed twice with 10 ml o f distilled/de-ionized water (BS 1377-1:2016,
and the rinsings added to the evaporating dish.
6.1 )
shall be wiped dry with a clean, dry paper towel or similar.
The evaporating dish and contents shall be placed into the oven and heated at (180 ±10) °C for 1 h.
The dish shall be allowed to cool in the desiccator to room temperature, and its mass m 2 determined
to 0.0005 g.
11.3.9 11.3.7 and 11.3.8 shall be repeated but heated in the oven for 30 min, until the difference between
successive weighings does not exceed 1 mg.
10
Whatman is a trademark of GE Healthcare. This information is given for the convenience of users of this document and does not constitute
an endorsement by the British Standards Institution of the named product. Equivalent products may be used if they can be shown to lead to
the same results.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 65
BS 1377‑3:2018
BRITISH STANDARD
11.4 Calculations
The total dissolved solids (TDS) (in mg/l) in each measured sample of water shall be calculated from
the equation:
TDS =
m 2 − m1
V
× 10 6
(57)
where
m1
is the mass of the dried evaporating dish (in g);
m2
is the mass of the dish with dissolved solids after the second or subsequent period of drying
at 180 °C (in g);
V
is the measured volume of the sample of water used (in ml).
The mean of the results shall be calculated if more than one sample has been tested. If they differ by
more than 10% of the mean value, the test shall be repeated starting with two new water samples.
11.5 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018,
Clause 11 , and shall contain the following information:
12
a)
the method of test used;
b)
the total dissolved solids (TDS) (in mg/l), in the water sample, to two significant figures;
c)
whether it was possible to filter the water sample free o f all traces o f turbidity;
d)
information about the origin of the water sample; and
e)
the information required by BS 1377‑1:2016,
10.1 .
Determination of the pH value
12.1 General
This clause describes the procedure for determining the pH value by the electrometric method, which
gives a direct reading of the pH value of a soil suspension in water. This method can also be used
for determining the pH value of a sample of ground water. The requirements of BS 1377‑1, where
appropriate, shall apply to this test method.
12.2 Reagents
12.2.1
12.2.2
All reagents shall be of recognized analytical reagent quality.
Commercially available pH 4, pH 7 and pH 10 buffer solutions or other pH values as required. The
buffer solutions shall be stored and controlled in accordance to manufacturer's instructions.
NOTE
12.2.3
Commercially available buffer solutions are available for a range of values, e.g. pH 1 to pH 13.
Alternatively buffer solutions can be made for example:
Buffer solution, pH 4.0. Dissolve 5.106 g of potassium hydrogen phthalate in distilled/de‑ionized
water (BS 1377‑1:2016,
6.1 ) and dilute to 500 ml.
Buffer solution, pH 9.2. Dissolve 9.54 g of sodium tetraborate (borax) in distilled/de‑ionized water
(BS 1377‑1:2016,
12.2.4
12.2.5
6.1 ) and dilute to 500 ml.
Potassium chloride. Saturated solution (for maintenance of the calomel electrode if used).
De-ionized water as specified in BS 1377-1.
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BRITISH STANDARD
BS 1377‑3:2018
12.3 Apparatus
12.3.1 Apparatus for preparation of test specimens
12.3.1.1 Balance, readable to 0.001 g.
12.3.1.2 Pestle and mortar, or a suitable mechanical crusher.
12.3.1.3 Test sieve, of 2 mm aperture size, with receiver.
12.3.1.4 Non-corrodible tray.
12.3.2 Apparatus for electrometric method of pH determination
12.3.2.1 pH meter, a bench pH meter and solid body combination pH electrode, with or without automatic
temperature correction. The apparatus should cover the range pH 1.0 to pH 14.0 and the scale shall
be readable and accurate to 0.05 pH units.
12.3.2.2
12.3.2.3
12.3.2.4
Three 100 ml glass or plastics beakers with cover glasses and stirring rods.
Two 500 ml volumetric flasks.
Wash bottle, preferably made of plastics, containing distilled/de‑ionized water (BS 1377‑1:2016, 6.1 ).
12.4 Preparation of sample
12.4.1
12.4.2
12.4.3
12.4.4
12.4.5
An initial sample o f the appropriate size specified in BS 1377-1:2016,
be obtained.
The sample shall be allowed to air‑dry by spreading out on a tray exposed to air at room temperature.
The sample shall be sieved on a 2 mm test sieve (if appropriate, guarded by a sieve of larger aperture)
and the retained particles other than stones crushed to pass through the 2 mm test sieve.
The stones shall be rejected, ensuring that no fine material adheres to them, e.g. by brushing. The
mass m 2 (in g) of the sample passing the 2 mm test sieve shall be recorded to the nearest 0.1%.
Throughout these and subsequent operations it shall be ensured that there is no loss o f fines.
The material passing the 2 mm test sieve shall be divided by successive ri ffling through the 15 mm
divider to produce a representative test sample of 30 g to 35 g.
12.5 pH determination
12.5.1
12.5.2
8.3 and Table 5 shall
From the sample obtained as described in
a 100 ml beaker.
12.4, (30 ±0.1) g of soil shall be weighed out and placed in
75 ml of distilled/de‑ionized water (BS 1377‑1:2016,
6.1 ) shall be added to the beaker, the
suspension shall be stirred for a few minutes, covered with a cover glass and allowed to stand for
at least 8 h.
12.5.3
12.5.4
NOTE The pH value of a soil suspension varies with the ratio of soil to water, an increase in dilution bringing the
pH closer to 7.
The suspension shall be stirred again immediately before testing.
The room temperature shall be recorded to 0.5 °C. The pH meter shall be calibrated by using the pH
4 and pH 10 buffers or with the appropriate buffer if lower or higher pH values are likely, following
the procedure recommended by the manufacturer including cleaning the electrode after each
measurement using deionized water and drying by gentle wiping with a clean tissue. The range shall
encompass a majority of test samples. The % slope (sensitivity) shall be recorded. If the slope is
outside the range 95% to 105%, the instrument shall be recalibrated.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 67
BS 1377‑3:2018
12.5.5
BRITISH STANDARD
Immediately after calibration, the pH 7 buffer shall be measured and the value recorded. If the value
obtained differs more than ±0.05 pH units from temperature‑corrected nominal value the instrument
shall be recalibrated.
12.5.6
12.5.7
Fresh aliquots of buffer solution shall be used each day.
The electrode shall be washed with distilled/de‑ionized water (BS 1377‑1:2016,
6.1 ) and dried.
Immersed in the soil suspension, two two or three readings of the pH of the suspension shall be taken
with brief stirrings between each reading. These readings shall agree to within 0.05 pH units before
being accepted.
12.5.8
NOTE The pH readings of the soil suspension should reach a constant value in about 1 min. No readings should be
taken until the pH meter has reached equilibrium.
The electrodes from the suspension shall be removed and washed with distilled/de‑ionized water
(BS 1377‑1:2016,
6.1 ) and dried. The calibration of the pH meter shall be re‑checked against one of
the standard buffer solutions.
12.5.9
12.5.10
If the instrument is out of adjustment by more than 0.05 pH units, it shall be set to the correct
adjustment and
12.5.5 to 12.5.8 repeated until consistent readings are obtained.
For short periods between measurements the electrodes shall be stored in pH 7 buffer. For longer
periods (e.g. overnight) electrodes shall be stored in a proprietary electrode storage solution as in the
manufacturer’s instructions.
12.5.11
If samples have pH values outside the calibrated range, the range shall be extended by analysing a
suitable buffer, e.g. pH 2 or pH 12, within the analytical run. This shall be recorded. The accredited
range is extended if the analysis of the additional buffer(s) shall be within ±0.05 pH units.
12.6 Quality control
A quality control material, prepared in‑house or purchased from an approved supplier, shall be
measured with each batch of samples.
NOTE
Pro ficiency testing using an appropriate scheme should be used.
12.7 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018, Clause
12, and shall contain the following information:
13
a)
the method of test used;
b)
the pH value of the soil suspension to the nearest 0.1 pH unit; and
c)
the information required by BS 1377‑1:2016,
10.1 .
Determination of electrical resistivity
13.1 Principle
The tests described in this clause are for the determination of the electrical resistivity of samples of
soil in the laboratory. The resistivity value indicates the relative capability of the soil to carry electric
currents from which the corrosiveness of the soil can be deduced, or for undisturbed samples can
be related to the resistivity of the ground. The soil resistivity is calculated from a measurement of its
electrical resistance and a factor depending on the sample geometry.
NOTE 1 The resistivity of earth materials depends primarily on the porosity, saturation, pore fluid resistivity,
conductive minerals content, usually clay minerals, and temperature.
NOTE 2 The laboratory test can also be compared to field test data.
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BRITISH STANDARD
BS 1377‑3:2018
13.2 Types of test and limitations
COMMENTARY ON
Three types of test are described, all of which are variants of the 4-point measurement of resistivity.
A fixed current is applied between two “outer” electrodes, whilst the potential difference (in Volts) is
then measured between two “inner” electrodes. The 2-point measurement system included in the 1990
version of this standard has been removed, as the resistance of the test cables and electrodes result in
higher measured values of soil resistivity.
The first method described is for undisturbed field samples in core liners or field samples extruded from
samplers. In this method a fixed current is applied between the outer electrodes (i.e. through the length
of the sample). The inner electrodes are used to measure the potential difference across either specific
intervals of interest, or regular “logging” intervals along the length of the sample.
The second method is similar to the first except that it applies to an undisturbed or compacted soil
sample, either trimmed to fit or compacted directly into a (rectangular) test cell fitted with electrodes
at either end of the sample, between which a fixed current is applied through the sample. The inner
electrodes are used to measure the potential difference across a fixed length of the sample. For coarse
soils and coarse silt the measurement container is flooded with water before applying the current.
The third method uses four probe electrodes inserted into a sample in a Wenner con figuration, the same
principle as used for the in-situ test described in of BS 1377-9:1990, (i.e. uniform spacing between
electrodes). A fixed current is passed between the outer electrodes and the potential difference between
the two inner electrodes is measured.
The type of test applicable depends largely on how the soil sample is presented to the test laboratory
(i.e. the type of container), the condition/stability of that sample as well as the sample soil type and
any specific sample attributes that need to be incorporated into the testing (i.e. testing of saturated
soil samples).
Soil samples that have been compacted in the laboratory contain a significant proportion of air voids,
unless the water content is appreciably higher than the optimum for the applied compactive effort
(see BS 1377-4). Air voids increase resistance and can reduce the contact between the soil and the
electrodes. These effects can be reduced by a thorough mixing of the soil to prevent segregation, but in
some instances it is better to use only the finer fraction of the soil, e.g. the material passing a 2 mm test
sieve. Where testing of fine soils is undertaken, the dimensions of the test sample can be reduced, but
the minimum sample dimension is not less than a factor of 10 times greater than the largest particle
size anticipated e.g. if the maximum particle size expected is 10 mm, the cross-section of a sample is
100 mm × 100 mm, with at least 100 mm between potential electrodes. For fine soils samples have a
cross-sectional area of at least 25 mm × 25 mm × 75 mm length.
Laboratory tests do not take account of changes in the soil characteristics that take place with time,
unless further tests are carried out at suitable intervals.
The test procedures for compacted soils are for single sets of measurements obtained at a particular
water content. Further tests might be carried out over a range of water contents, saturation and
densities so that the effect of changes in test conditions can be measured.
The results of these tests are expected to be interpreted by a trained specialist, for instance an
engineering geophysicist.
1 3. 2
5. 1
13.3 Measurement of resistivity: undisturbed cylindrical samples
13.3.1 General
This procedure enables the electrical resistivity of an undisturbed sample of soil to be measured in
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© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 69
BS 1377‑3:2018
BRITISH STANDARD
grained soils, containing up to gravel‑size particles, and some extremely to very weak rocks, and is
the preferred method for soils obtained in a sampling tube from a borehole.
NOTE 1 Samples may also be prepared from a block sample taken from an open excavation, but re-sampling to fit
the sample into a cylindrical container (e.g. core liner) is likely to unduly disturb the sample, particularly in the case
of coarse soils, where, if the testing of an undisturbed sample is required, the use of the method described in
for
a trimmed sample is suggested instead.
1 3. 4
NOTE 2 Where testing is to be undertaken on (extremely) weak rocks, in order for electrodes to be inserted into the
sample, some pre-drilling of holes in the sample might be required in order to insert the potential electrodes.
The requirements of BS 1377‑1, where appropriate, shall apply to this test method.
13.3.2 Apparatus
13.3.2.1 Rigid cylindrical container (referred to as the test container) of non‑conducting material at least
100 mm internal diameter and 400 mm to 1 000 mm long. For shorter core samples requiring
extruding, it might be more appropriate to trim the sample for use with the “open container”
method described in
conductive plastic).
13.4. The sampling tube may be used if it is of suitable material (i.e. non‑
NOTE 1 Rigid plastic piping of PVC/ polyethylene or polypropylene has been found to be suitable.
NOTE 2 For block samples it is more appropriate to trim the sample for use with the “open container” method
, as re-sampling to fit a core liner is likely to further disturb/consolidate the sample.
described in
13.3.2.2
13.3.2.3
1 3. 4
NOTE 3 Measures should be taken to avoid water loss.
Suitable means of extruding the sample from the sampling tube and into the test container, such as that
referred to in BS 1377‑1:2016,
. This is used when an undisturbed sample is not received in a
suitable non‑conducting container.
9.2.2
Two metal discs, of a diameter about 1 mm less than that of the test container, to act as outer
“current” electrodes, each having a recessed terminal for connecting to insulated copper wire. To
avoid potential issues with corrosion it is suggested that these be constructed from stainless steel
(see Figure 6).
13.3.2.4
Two metal probe electrodes of 2 mm to 6 mm diameter, with pointed ends, to act as inner “potential”
electrodes, each with a terminal for connecting to insulated copper wire.
NOTE 1 To avoid potential issues with corrosion it is suggested that these be constructed from stainless steel.
NOTE 2 The potential electrodes should be separated by at least 50 mm and for all measurements undertaken, be
placed at a distance at least equivalent to the separation used, from the nearest current electrode at the end of the
sample. Also, the separation between the potential electrodes should be significantly (at least 2 times) greater than
the maximum (anticipated) clast size.
70 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
Figure 6 — Testing undisturbed cylindrical samples
Key
1
Potential electrodes inserted through pre‑drilled holes in sample container
2
Cylindrical container of 400 mm‑1000 mm length and internal diameter of at least 100 mm
3
Switched d.c. current source (Amps) and potential difference (Volts) measurements to be undertaken
using a calibrated resistivity test meter
4
f
f
f
reach the mid‑point of the sample A)
5
Outer (stainless steel) current disc electrodes of diameter 1 mm less than test container
(i.e. core liner) B)
A)
The minimum separation shall be 50 mm or twice the maximum expected clast size.
I
B)
13.3.2.5
13.3.2.6
13.3.2.7
13.3.2.8
13.3.2.9
13.3.2.10
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Current electrodes shall be well coupled to the sample ends, which shall be trimmed if necessary.
Calibrated resistivity test meter
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measurements. The instruments shall have a performance conforming to BS 89, class 2.5, and shall be
re‑calibrated at intervals not exceeding 2 years.
NOTE If a test is unduly prolonged or if the electrodes are not properly cleaned before use a d.c. system can cause
polarization effects in soil leading to a resistivity higher than the actual value.
Insulated copper wire
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suitable terminals to ensure good electrical contact.
NOTE
Standard copper wire of about 1.5 mm 2 cross-sectional area is suitable.
Apparatus for the determination of water content, as described in BS EN ISO 17892‑1.
Sample trimming tools, e.g. trimming knife, spatula, end‑trimming tool.
Emery paper, of 0 or 00 grade, or steel wool.
Calibrated thermometer, readable to 1 °C (see BS 5930).
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 71
BS 1377‑3:2018
BRITISH STANDARD
13.3.2.11
13.3.2.12
Balance, suitable for determining the sample mass to a precision of 0.1% of the sample mass.
Means of measuring the sample dimensions and potential electrode positions, such as a steel rule
13.3.2.13
Means of drilling clearance holes in the sample tube for potential electrodes, such as a hand drill with
graduated to 0.5 mm or Vernier callipers.
bit diameter 1 mm greater than that of the potential electrodes to be used.
13.3.3 Procedure
13.3.3.1 Preparation of undisturbed sample
13.3.3.1.1 The sample shall be prepared and set up for the test as described in 13.3.3.1.2 to 13.3.3.1.9 .
to
NOTE
(plastic) container.
1 3 . 3. 3. 1 . 2
do not apply if the sample is received in a suitable non-conducting
1 3. 3. 3. 1 . 3
13.3.3.1.2
The internal diameter D shall be measured to the nearest 0.5 mm.
13.3.3.1.3
The sample shall be extruded from the sampling tube, or trimmed from the block sample, and the
sample shall be inserted into the test container with the minimum of disturbance and loss of water.
13.3.3.1.4
13.3.3.1.5
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container and just inside the ends. The soil shall be protected from water loss.
The contact surfaces of the disc electrodes shall be cleaned by rubbing with emery paper or steel wool
to give a shiny surface, then wash with clean water and wipe dry with a clean cloth or paper towel.
NOTE
13.3.3.1.6
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Occasional small patches of corrosion that are difficult to remove are of no consequence.
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and gently tampered to ensure a good contact.
The location of all "potential" electrode positions required to undertake the desired measurements
shall be measured and marked along the length of the sample container.
NOTE Measurements may be undertaken to target specific intervals along the sample (i.e. where obvious visible
variations in soil composition are apparent), or at regular intervals (suggested to be equal to the separation of the
potential electrodes) to undertake a log of the entire length of the sample.
13.3.3.1.8
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electrodes for all planned measurements. These holes shall be covered with insulation tape to reduce
water loss until measurements are to be made.
NOTE Care should be taken when drilling the clearance holes so that as little deformation of the sample
is induced as possible. Ideally only the walls of the sampling container should be penetrated, with minimal
disturbance of the surface of the soil sample. Minor disturbance of <5 mm from the surface of the sample is
considered acceptable.
13.3.3.1.9
Prior to undertaking the resistance measurements, the sample(s) shall be allowed to reach the
ambient temperature of the laboratory in which the measurements will be made.
72 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
NOTE Resistance measurements should be made in a temperature controlled lab with a maximum anticipated
temperature fluctuation of (±2 )°C.
13.3.3.2 Measurement of resistivity
13.3.3.2.1
13.3.3.2.2
The terminals on the outer "current" electrodes shall be connected to the current/output terminals of
the resistivity meter with the insulated copper wire.
The potential electrodes shall be inserted at the required test position through the pre‑drilled clearance
holes to a depth equivalent to the centre of the sample. If it is not possible to insert an electrode due
to the presence for example, a coarser particle, a new clearance hole shall be drilled (moving toward
13.3.3.1.8 . The new
the alternative potential electrode position), following the process described in
resulting separation between the potential electrodes shall be noted and used to calculate the sample
resistivity.
13.3.3.2.3
The terminals on the inner "potential" electrodes shall be connected to the potential/input terminals
of the resistivity meter with the insulated copper wire. A suitable current,
R
across the electrodes and the resulting resistance
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initially be set to the minimum current setting available on the measurement device being used. This
shall be increased in single increments until a stable (repeatable) resistance is measured. A current of
about 10 mA is suitable for many soils, but an optimum current shall be determined through testing.
NOTE
Some instruments automatically change the current to a suitable value.
13.3.3.2.4 13.3.3.2.2
13.3.3.2.3
and
shall be repeated to obtain two further repeat measurements (three
measurements in total).
13.3.3.2.5
Further measurements shall be undertaken at each desired test position as required.
13.3.3.2.6
The sample and ambient temperature shall be taken immediately after the test and recorded to the
13.3.3.2.7
The sample shall be extruded from the container and representative specimens taken for the
13.3.3.2.8
nearest 1 °C.
determination of water content, as described in BS EN ISO 17892‑1.
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variations in soil composition, for example, water content samples shall be taken from each of the
measurement intervals. Where regular measurement intervals are undertaken, water content samples
13.3.3.2.9
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The electrodes shall be cleaned and dried.
13.4 Measurement of resistivity: open container method
13.4.1 General
This procedure is for the measurement of the electrical resistivity of soil material that has been
collected as bulk (disturbed) sample or as an undisturbed block sample. This method is also
appropriate for core samples that might arrive in an unsuitable container, i.e. electrically conductive
or damaged, and that are unsuitable for transferring to a new cylindrical container. Samples are
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© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 73
BS 1377‑3:2018
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BRITISH STANDARD
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relatively free‑draining materials into which water can percolate easily can also be undertaken using
this method through saturating the sample by adding water of known resistivity.
The requirements of BS 1377‑1, where appropriate, shall apply to this test method.
13.4.2 Apparatus
13.4.2.1 Rectangular box with transparent sides, of internal dimensions approximately 230 mm long,
1
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interior and 15 mm from each end of the box.
13.4.2.2
13.4.2.3
13.4.2.4
13.4.2.5
13.4.2.6
NOTE The insertion of stainless steel springs allowing 5 mm-10 mm of free movement between the ends of the
box and the current electrodes helps to maintain the contact with the soil sample, where samples are prepared from
larger (i.e. undisturbed) specimens. For coarse soils and coarse silt, the addition of small holes in the electrodes will
allow the passage of water. The electrodes are fitted with terminals for connecting insulated copper wire. The sides
of the box are of suitable non-conducting material.
The general arrangement shall be as shown in Figure 7, Figure 8a and Figure 8b.
NOTE Disturbed samples may be compacted using standard Proctor compaction methods (see BS 1377-4) or nonstandards methods as required. The test samples are then trimmed to size from the completed mould. If a standard
proctor mould or core sample (of less than 140 mm diameter) requires trimming for testing using the open
container method, it will be necessary to use a smaller cross-section test box than suggested above. The suggested
designs illustrated in Figure 7, Figure 8a and Figure 8b can be scaled down.
Two clean stainless steel probe electrodes of 2 mm to 6 mm diameter, with pointed ends, to act as inner
“potential” electrodes, each with a terminal for connecting to insulated copper wire.
Potential electrodes, separated by at least 50 mm and placed at a distance at least equivalent to the
separation used, from the nearest current electrode at the end of the sample.
Calibrated resistivity test meter
measurements (see
13.3.2.5 ).
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The instruments shall have a performance conforming to BS 89, class 2.5 and shall be re‑calibrated at
intervals not exceeding 2 years.
74 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
Figure 7 — Design for open container for resistivity tests on saturated coarse soil
Key
1
2
3
4
5
6
Switched d.c. current source (Amps) and potential difference (Volts) measurements undertaken using
a calibrated resistivity meter
Current electrodes made from stainless steel with holes drilled through for testing saturated samples
Potential electrodes made from 2 mm‑6 mm stainless steel or copper (e.g. phosphor bronze)
Current electrode terminal connection
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sample to be compacted in place
End‑caps sealed watertight
NOTE Sample container can be fabricated from clear, non-conductive material which permits some evaluation of
potential air-voids with a sample.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 75
BS 1377‑3:2018
BRITISH STANDARD
Figure 8a — Design for reduced size open container for resistivity tests on fine-grain cohesive soil — Example of a
small resistivity test cell for use with fine-grained soils
Key
1
2
Current electrodes sprung using elastic bands to ensure good coupling with soil sample
Potential electrodes inserted to the centre of the soil sample
NOTE This design is not watertight and, therefore, is not suitable for testing of materials in which water is lost
through the holes.
76 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
Figure 8b — Design for reduced size open container for resistivity tests on fine-grain cohesive soil — Example of a
reconstituted soil sample trimmed from a Proctor mould
Key
1
Switched d.c. current source (Amps) and potential difference (Volts) measurements to be
undertaken using a calibrated resistivity test meter
NOTE This design is not watertight and, therefore, is not suitable for testing of materials in which water will be
lost through the holes.
13.4.2.7
13.4.2.8
13.4.2.9
13.4.2.10
13.4.2.11
13.4.2.12
13.4.2.13
13.4.2.14
13.4.2.15
Insulated copper wire
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suitable terminals to ensure good electrical contact.
NOTE
Standard copper wire of about 1.5 mm 2 cross-sectional area is suitable.
Apparatus for the determination of water content, as described in BS EN ISO 17892‑1.
Sample trimming tools, e.g. trimming knife, spatula, end‑trimming tool.
Steel straightedge, about 150 mm long.
Emery paper, of 0 or 00 grade, or steel wool.
Thermometer, readable to 1 °C.
Balance, suitable for determining the sample mass to a precision of 0.1% of the sample.
Means of measuring the sample dimensions and potential electrode positions, such as a steel rule
graduated to 0.5 mm.
In addition, for compacted samples, the equipment in
13.4.2.15.1 to 13.4.2.15.6 .
13.4.2.15.1
Test sieve, 10 mm aperture size.
13.4.2.15.2
1 l measuring cylinder.
13.4.2.15.3
Large metal tray, e.g. 900 mm square and 80 mm deep.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 77
BS 1377‑3:2018
BRITISH STANDARD
13.4.2.15.4
Large metal scoop.
13.4.2.15.5
Small tools, such as a spatula and garden trowel.
13.4.2.15.6
Watertight containers, such as strong polyethylene bags.
13.4.3 Procedure
13.4.3.1 Preparation of undisturbed sample
13.4.3.1.1 The contact surfaces of the electrodes shall be cleaned by rubbing with emery paper to give a shiny
surface, then wash with clean water and wipe dry with a clean cloth. The clean electrodes shall be
inserted into the test container.
NOTE
13.4.3.1.2
Occasional small patches of corrosion that are difficult to remove are of no consequence.
The internal dimensions of the sample container of the box shall be measured to the nearest 0.5 mm.
The mass of the empty test container (with current electrodes in place) shall be measured and
recorded as m 1 .
13.4.3.1.3
The sample shall be extruded from the sample tube. This sample or block sample shall be trimmed to
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shall be placed into a resealable plastic bag.
13.4.3.1.4
Representative samples of the trimmings shall be taken for water content determinations, as described
in BS EN ISO 17892‑1.
NOTE If the current electrodes are sprung, the length of the trimmed sample is not critical and may be shorter
(up to 5 mm shorter) than the sample container. The width of the sample should be as close to that of the soil
compartment as possible.
13.4.3.1.5
The sample shall be inserted into the test container with the minimum of disturbance and loss of
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m , shall be measured and the mass of the soil used calculated by
2
subtracting the mass of the empty test container.
13.4.3.2 Preparation of compacted sample — compaction in test container — partially saturated soils
13.4.3.2.1
13.4.3.2.2
The spacers for the current electrodes shall be placed in the sample container before
compacting the sample.
The contact surfaces of the electrodes shall be cleaned by rubbing with emery paper to give a shiny
surface, then washed with clean water and wiped dry with a clean, dry cloth.
NOTE
13.4.3.2.3
Occasional small patches of corrosion that are difficult to remove are of no consequence.
The internal dimensions of the soil compartment of the box shall be measured to the nearest 0.5 mm.
78 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
13.4.3.2.4
13.4.3.2.5
13.4.3.2.6
BS 1377‑3:2018
The mass of the empty test container (with current electrodes in place) shall be measured to 0.1%.
If necessary, large particles shall be removed by passing the soil through a 10 mm sieve, and spreading
out the sample on a tray. The percentage by mass of particles removed shall be calculated.
If the water content of the soil is to be adjusted, the appropriate amount of water of known resistivity
shall be added (see note), or the soil shall be allowed to partially dry at room temperature. The sample
shall be mixed thoroughly to ensure a uniform distribution of water. The sample shall be placed in an
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NOTE
13.4.3.2.7
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.
If possible a sample of the water that will be used on site should be used or water with the same resistivity.
A representative sample shall be taken for the determination of the water content, as described in
BS EN ISO 17892‑1, to check that the desired water content has been achieved. If this is not the case
13.4.3.2.6 shall be repeated.
NOTE If the desired water content has not been reached, the testing should either be performed at the achieved
water content if considered appropriate to do so, or the sample should be re-mixed and the water content modified
until an acceptable water content has been reached.
in accordance with
1 3 . 4. 3. 2 . 6
13.4.3.2.8
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the box in three equal layers and compact each layer by applying the appropriate compactive
effort ensuring that the compaction is uniform across the sample, for instance see BS 1377‑4. The
c
13.4.3.2.9
13.4.3.2.10
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compactive effort required for each layer shall be determined by trial beforehand.
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13.4.3.2.11
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subtracting the mass of the empty test container.
13.4.3.3 Preparation of compacted sample — compaction in test container — coarse soils
and coarse silt
13.4.3.3.1
13.4.3.3.2
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.
The contact surfaces of the electrodes shall be cleaned by rubbing with emery paper to give a shiny
surface, then wash with clean water and wipe dry with a clean, dry cloth.
NOTE
Occasional small patches of corrosion that are difficult to remove are of no consequence.
13.4.3.3.3
The internal dimensions of the soil compartment of the box shall be measured to the nearest 0.5 mm.
13.4.3.3.4
The mass of the empty test container (with current electrodes in place) shall be measured.
13.4.3.3.5
If necessary, large particles shall be removed by passing the soil through a 10 mm test sieve and
measure mass of particles removed.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 79
BS 1377‑3:2018
13.4.3.3.6
13.4.3.3.7
13.4.3.3.8
T
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BRITISH STANDARD
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.
Representative specimens of the soil for determination of the water content shall be taken, in
accordance with BS EN ISO 17892‑1.
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equal layers, and each layer shall be compacted by applying the appropriate compactive effort using
the steel tamping bar.
13.4.3.3.9
13.4.3.3.10
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and blows and compactive effort required for each layer shall be determined by trial beforehand.
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by subtracting the mass of the empty test container.
13.4.3.4 Measurement of resistivity — partially saturated soils (undisturbed and compacted samples)
13.4.3.4.1
13.4.3.4.2
The terminals on the outer “current” electrodes shall be connected to the current/output terminals of
the resistivity meter with the insulated copper wire.
The potential electrodes at the required test positions (an initial separation 100 mm is suggested, with
electrodes located 50 mm from the nearest current electrode) shall be inserted to a depth equivalent
to the centre of the sample.
13.4.3.4.3
If it is not possible to insert an electrode due to the presence of a coarse fragment for example, the
electrode position shall be moved toward the alternative potential electrode position.
NOTE The new resulting separation between the potential electrodes should be noted for later calculation of soil
resistivity.
13.4.3.4.4
The terminals on the inner “potential” electrodes shall be connected to the potential/input terminals
13.4.3.4.5
A suitable current, I (in A) shall be applied across the electrodes and the resulting resistance,
of the resistivity meter with the insulated copper wire.
R
(
i
n
Ω
)
shall be recorded.
NOTE The applied current should initially be set to the minimum current setting available on the measurement
device being used. This should be increased in single increments until a stable (repeatable) resistance is measured.
13.4.3.4.6 13.4.3.4.5 shall be repeated to obtain 2 further repeat measurements (3 measurements in total).
13.4.3.4.7
13.4.3.4.8
The temperature of the soil sample and the ambient temperature of the laboratory facility in which the
measurements were undertaken, shall be undertaken immediately after the test.
The sample from the test container shall be removed and two specimens for the determination of
water content shall be taken, as described in BS EN ISO 17892‑1.
80 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
13.4.3.4.9
BS 1377‑3:2018
The electrodes shall be cleaned and dried with a suitable cloth before storing.
13.4.3.5 Measurement of resistivity — coarse soils
13.4.3.5.1
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measured to 1 °C.
NOTE Distilled/de-ionized water (BS 1377-1:2016, ) should be used unless the material in-situ will be below
the water table, in which case water from the site should be used.
6. 1
13.4.3.5.2
The volume of water remaining in the measuring cylinder shall be recorded and the volume of water
used calculated from the difference in values.
13.4.3.5.3
The terminals on the outer "current" electrodes shall be connected to the current/output terminals of
13.4.3.5.4
The potential electrodes shall be inserted at the required test positions (an initial separation of
the resistivity meter with the insulated copper wire.
100 mm is suggested, with electrodes located 50 mm from the nearest current electrode) to a depth
equivalent to the centre of the sample.
13.4.3.5.5
If it is not possible to insert an electrode due to the presence of a coarse fragment for example, the
electrode position shall be moved to the alternative potential electrode position.
NOTE The new resulting separation between the potential electrodes should be noted for later calculation of soil
resistivity.
13.4.3.5.6
The terminals on the inner “potential” electrodes shall be connected to the potential/input terminals
13.4.3.5.7
A suitable current, I (in A) shall be applied across the electrodes and the resulting resistance,
of the resistivity meter with the insulated copper wire.
R
,
(
i
n
Ω
)
shall be recorded.
NOTE The initial applied current should initially be set to the minimum current setting available on the
measurement device being used. This should be increased in single increments until a stable (repeatable) resistance
is measured. A current of about 10 mA is suitable for many soils, but for soils of very high resistivity the impressed
voltage might have to be increased.
13.4.3.5.8 13.4.3.5.7 shall be repeated to obtain 2 further repeat measurements (3 measurements in total).
13.4.3.5.9
The temperature of the soil sample and the ambient temperature of the laboratory facility in which the
measurements were undertaken, shall be measured and recorded immediately after the test.
13.4.3.5.10 13.4.3.5.7 to 13.4.3.5.9 shall be repeated after allowing the soil to stand for 1 h after saturation, and
topping up with water if necessary. The temperature of the water shall be measured.
NOTE
Alternating current will cause a temperature rise if continued for a length of time.
13.4.3.5.11
The sample shall be removed from the test container and two specimens for the determination of
13.4.3.5.12
The electrodes and box shall be cleaned and dried after removing the soil.
water content shall be taken from the test specimen, as described in BS EN ISO 17892‑1.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 81
BS 1377‑3:2018
BRITISH STANDARD
13.5 Measurement of resistivity: Wenner probe method
13.5.1 General
This procedure enables the electrical resistivity of an undisturbed or disturbed sample of soil to be
m
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5.1 ).
l
BS 1377‑9:1990,
a
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f
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d
(
s
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e
The test is suitable for samples of the most types of soils, but might not provide repeatable
results where there is an appreciable amount of gravel‑size particles. Care should be taken when
d
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y
greater (ideally ten times greater) than the size of the largest soil fraction expected within the soil
sample to be tested.
The requirements of BS 1377‑1, where appropriate, shall apply to this test method.
13.5.2 Apparatus
13.5.2.1 Test container of non-conducting material, comprising either a rigid cylindrical container as described
in 13.2 (with clearance holes drilled in the side of the container for insertion of the probes, according
to the choice of Wenner array dimensions) or an open container as described in 13.3 .
13.5.2.2 Suitable means of extruding the sample, from the sampling tube and into the test container, as given in
BS 1377‑1:2016, 9.2.2 .
13.5.2.3
NOTE
Four steel probe electrodes of equal length with pointed ends in alignment and equally spaced (the
Figure 9).
W
e
13.5.2.4
This is used when an undisturbed sample is not received in a suitable non-conducting container.
n
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r
NOTE
c
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f
i
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u
r
a
t
i
o
n
,
s
e
e
Probes 2 mm to 6 mm diameter about 25 mm apart have been found to be satisfactory in clay soils.
13.3.2.5 to 13.3.2.13
f
13.4.2.15.1 to 13.4.2.15.6 if a compacted sample is to be prepared.
A
p
p
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a
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a
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t
h
82 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
e
a
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d
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p
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i
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d
i
n
BRITISH STANDARD
BS 1377‑3:2018
Figure 9 — Circuit diagram for resistivity test using Wenner probes
Key
1
Switched d.c. current source (Amps) and potential difference (Volts) measurements to be undertaken
using a calibrated resistity test meter
2
Electrodes consisting of 2 mm‑6 mm diameter steel or copper (phosphor bronze) probes
3
Soil sample in a non‑conductive container
a
Probe spacing
b
Not less than 25 mm
NOTE Between electrodes there should be a minimum separation of 25 mm or twice the maximum
expected clast size.
13.5.3 Measurement of geometric factor of sample container
13.5.3.1 General
T
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e
i
n
f
l
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n
c
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o
f
t
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W
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d
r
e
s
i
s
t
a
n
c
e
o
f
(R) in site surveys can be simply accounted for when calculating soil resistivity, rs
the equation:
=
rs
s
(
o
i
i
l
n
m
Ω
a
m
t
e
)
,
r
u
i
a
s
i
l
s
n
g
2 π aR
1000
(58)
where
is the centre‑to‑centre distance between adjacent electrodes (in mm);
a
R
T
h
e
a
s
s
u
i
m
p
t
i
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e
m
a
a
v
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a
g
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m
g
a
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r
d
a
i
s
n
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g
e
d
t
h
r
i
e
s
s
g
i
s
e
t
a
o
n
m
c
e
e
(
t
r
i
i
n
Ω
f
c
a
)
c
.
t
o
r
f
o
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t
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e
W
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u
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a
t
i
o
n
,
h
o
w
e
v
e
r
,
w
i
l
l
be invalid for the purposes of laboratory testing of small samples, which will be affected by the depth
to which the electrodes are inserted into the sample approaching the separation between electrodes
and the relatively close proximity of the electrically insulating boundaries of the sample, such that the
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s
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t
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v
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y
o
f
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s
o
i
l
s
a
m
p
l
e
.
Given the potentially varied size of samples to be tested, the geometric factor of a sample container
(and intended electrode arrangement to be used) shall be determined prior to the testing of soil
m
a
t
e
r
i
a
l
s
.
T
h
i
s
c
a
n
b
e
a
c
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v
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d
b
y
f
i
l
l
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n
g
t
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e
(
w
a
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r
t
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h
t
)
c
o
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t
a
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r
w
i
t
h
a
n
e
q
u
i
v
a
l
e
n
t
v
o
l
u
m
e
o
f
water with known resistivity (rw) and measuring the resistance (Rw). The geometric factor (Gf) is then
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 83
BS 1377‑3:2018
BRITISH STANDARD
equal to rw/ Rw. This geometric factor can then be applied to all subsequent measurements of soil
resistance to provide a corrected soil resistivity measurement, such that;
rs
= Rs × G f
(59)
NOTE Whilst a measurement of the geometric factor may be undertaken using a single fluid of known resistivity,
a number of fluids of differing resistivity should be used, spanning the expected range of soil resistivity that may be
encountered as a check that a consistent geometric factor has been measured (the geometric factor is intrinsic to
the dimensions of both the container and the position, depth of insertion and separation of the electrodes and all of
these factors should remain constant for measurements of both the geometric factor and subsequent measurement
of soil resistivity). For example, fluids with a resistivity of 1 Ωm, 10 Ωm, 30 Ωm and 100 Ωm might be appropriate.
13.5.3.2 Apparatus
13.5.3.2.1
Empty test container (as described in 13.5.2.1 ) that has been made watertight.
13.5.3.2.2
Four steel probe electrodes of equal length with pointed ends
W
e
n
n
e
r
NOTE
13.5.3.2.3
13.5.3.2.4
c
o
n
f
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u
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a
t
i
o
n
,
s
e
e
Figure 9 ).
Identical probes as used for the soil testing should be used.
Suitable means of mounting electrodes
A
p
p
a
in alignment and equally spaced (the
r
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,
a
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13.3.2.5 , 13.3.2.6 , 13.3.2.9 and 13.3.2.10.
13.5.3.3 Procedure
13.5.3.3.1
T
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e
m
p
t
y
w
a
t
e
r
t
i
g
h
t
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t
a
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r
s
h
a
l
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p
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o
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a
f
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f
l
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f
a
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d
f
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c
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p
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e
l
y
w
i
t
h
a
f
l
u
i
d
of a known resistivity.
NOTE 1 Fluids of known resistivity can be purchased for calibration purposes. Alternatively fluids can be produced
using specific concentrations of NaCL in water (g/l). Details of the relationship between electrical conductivity
and NaCl concentration can be found from the CRC Handbook of Chemistry and Physics [4] for example, but
other references can be used as appropriate. The actual source used for the calibration fluid should be referenced
when presenting test results measured using the Wenner Array: however, the actual conductivity (the inverse of
resistivity) of any solution produced should be con firmed using a calibrated conductivity meter prior to use for
calibration purposes.
NOTE 2 Fluids of known resistivity should be produced to relate to resistivity at 20 °C.
13.5.3.3.2
13.5.3.3.3
The contact points of the steel electrodes shall be cleaned by rubbing with emery paper or steel wool
to give a shiny surface.
The clean electrodes shall be placed into the position in which they will be used for the soil testing.
This shall relate to both the position and depth of insertion into the test container.
NOTE This procedure likely requires the fabrication of a mount to support the electrodes in the desired position
in a repeatable manner.
13.5.3.3.4
13.5.3.3.5
The outer “current” electrodes shall be connected to the current/output terminals of the resistivity
meter with the insulated copper wire.
The inner “potential” electrodes shall be connected to the potential/input terminals of the resistivity
meter with the insulated copper wire.
84 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
13.5.3.3.6
BS 1377‑3:2018
I (in A)
A suitable current,
Ω
)
r
e
c
o
r
d
e
d
R (in
shall be appled across the electrodes and the resulting resistance
.
NOTE The initial applied current should initially be set to the minimum current setting available on the
measurement device being used. This should be increased in single increments until a stable (repeatable) resistance
is measured.
13.5.3.3.7 13.5.3.3.5
13.5.3.3.6
and
shall be repeated to obtain 2
further repeat measurements
(3 measurements in total).
13.5.3.3.8
13.5.3.3.9
The water and ambient temperature of the laboratory facility in which the measurements were
undertaken shall be taken immediately after the test and recorded to the nearest 1 °C.
I
ff
u
r
t
h
e
r
m
a
s
u
r
m
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t
s
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f
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s
o
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,
t
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t
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s
t
13.5.3.3.1 to 13.5.3.3.8 .
6.1 ) water, before
c
o
n
t
a
i
n
e
r
s
h
a
l
l
b
e
The electrodes shall be cleaned and dried with a suitable cloth before storing.
13.5.3.4 Calculation of G
13.5.3.4.1
e
emptied and washed thoroughly with distilled/de‑ionized water (BS 1377‑1:2016,
repeating
13.5.3.3.10
e
I
f
t
h
t
h
e
e
f
l
t
e
u
i
s
d
t
i
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s
m
k
n
p
o
e
f
r
a
w
n
t
u
)
,
r
e
t
h
o
e
c
f
o
t
h
r
r
e
e
f
l
s
u
p
i
o
d
n
Tw (in °C) was different from 20 °C (at which the resistivity (rw20 ) of
f Tw1 (in °C) is rwTC and
d
i
n
g
r
e
s
i
s
t
i
v
i
t
y
(
i
n
Ω
)
a
t
t
h
e
t
e
s
t
t
e
m
p
e
r
a
t
u
r
e
o
shall be calculated from:
rwTC =
13.5.3.4.2
rw 20
1 + 0 . 02 ( Tw 1 − 20 )
(60)
The geometric factor (Gf) shall be calculated from the equation:
r
Gf = wTC
Rw
(61)
where
Rw
NOTE
i
s
t
h
e
m
e
a
s
u
r
e
d
r
e
s
i
s
t
a
n
c
e
o
f
t
h
e
f
l
u
i
d
t
e
s
t
e
d
.
Where the test is undertaken at 20 °C, rw20 may be used in the place of rwTC.
13.5.3.4.3 13.5.3.4.1 and 13.5.3.4.2
s
h
a
l
l
b
e
r
e
p
e
a
t
e
d
f
o
r
e
a
c
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t
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s
t
u
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d
e
r
t
a
k
e
n
u
s
i
n
g
a
f
l
u
i
d
,
o
r
f
l
u
i
d
s
o
f
d
i
ff
e
r
e
n
t
resistivity.
13.5.3.4.4
The mean average
Gf
s
h
a
l
l
b
e
c
a
l
c
u
l
a
t
e
d
w
h
e
r
e
t
e
s
t
s
u
s
i
n
g
t
w
o
o
r
m
o
r
e
f
l
u
i
d
s
o
f
d
i
ff
e
r
e
n
t
r
e
s
i
s
t
i
v
i
t
y
have been undertaken.
NOTE Each of the measurements of Gf should differ by not more than 5% from any of the other measurements
undertaken when testing a single sample container.
13.5.3.4.5
The mean Gf as measured shall be used, to convert all future measurements of soil resistance into soil
resistivity undertaken in the test container used (as well as for identical test containers that may also
be used), as long as the electrode type, position and depth of insertion remains consistent with that
used to measure
Gf and assuming that no deformation/alteration of the test container has occurred,
using the equation:
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 85
BS 1377‑3:2018
rs
13.5.3.4.6
BRITISH STANDARD
= Rs × G f
(62)
The geometric factor shall be calculated using the formula given in
13.5.3.4.2 and only relates to the
electrode spacing used during the calibration process. A separate geometric factor shall be required
for each electrode spacing used for the resistivity testing using the Wenner Array.
13.5.4 Procedure
13.5.4.1 Preparation of undisturbed sample
Undisturbed samples shall be prepared as in
13.4.3.1 .
13.5.4.2 Preparation of compacted sample
13.4.3.2 .
13.5.4.3 Measurement of resistivity — partially saturated soil samples
Compacted sample shall be prepared as in
13.5.4.3.1
The four (equally spaced) electrodes shall be inserted at the required test position, through pre‑drilled
13.5.4.3.2
If it is not possible to insert an electrode due to the presence of gravel for example, the electrode shall
clearance holes (if required), to a depth equivalent to the centre of the sample.
be moved to a new position where the equal spacing can be maintained.
NOTE Whilst it might be possible to move a single electrode and maintain the equal spacing required for this test,
it is likely that all electrodes will need to be moved to a new location.
13.5.4.3.3
The terminals on the outer “current” electrodes shall be connected to the current/output terminals of
the resistivity meter with the insulated copper wire. The terminals on the inner “potential” electrodes
shall be connected to the potential/input terminals of the resistivity meter with the insulated
copper wire.
13.5.4.3.4
A suitable current, I (in A), shall be applied across the outer electrodes and the resulting resistance
(
i
n
Ω
)
b
e
t
w
e
e
n
t
h
e
i
n
n
e
r
e
l
e
c
t
r
o
d
e
s
r
e
c
o
r
d
e
d
R
.
NOTE The applied current should initially be set to the minimum current setting available on the measurement
device being used. This should be increased in single increments until a stable (repeatable) resistance is measured. A
current of about 10 mA is suitable for many soils.
13.5.4.3.5 13.5.4.3.4 shall be repeated to obtain two further repeat measurements (three measurements in total).
13.5.4.3.6
Further measurements shall be taken at each desired test position (if testing undisturbed
cylindrical samples).
13.5.4.3.7
The temperature of the soil sample and the ambient temperature of the laboratory facility in which the
13.5.4.3.8
The sample shall be extruded from the container (if required) and representative specimens shall be
measurements were undertaken, shall be measured and recorded immediately after the test.
taken for the determination of water content, as described in BS EN ISO 17892‑1.
NOTE Where resistivity measurements target specific intervals of a sample (i.e. based on significant visible
variations in soil composition for example), water content samples should be taken from each of the measurement
86 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
intervals. Where regular measurement intervals are undertaken, water content samples should be taken to reflect
any significant variation of soil composition, as well as any significant change in calculated soil resistivity.
13.5.4.3.9
The electrodes shall be cleaned and dried with a suitable cloth before storing.
13.5.4.4 Preparation of saturated coarse soil
13.4.3.3 .
13.5.4.5 Measurement of resistivity — saturated coarse soil samples
The preparation of saturated coarse soil shall be as given in
13.5.4.5.1
T
i
h
n
e
t
o
s
o
i
t
h
l
e
s
a
m
w
a
p
t
e
l
e
r
s
c
h
h
a
a
l
l
m
b
b
e
e
s
r
s
a
t
u
u
n
r
a
t
i
l
t
e
a
d
l
l
b
c
y
h
p
a
o
m
u
b
r
e
i
r
n
s
g
w
a
a
r
e
t
e
c
o
r
f
m
r
o
p
l
m
e
a
t
e
l
f
i
y
l
l
f
i
e
l
l
d
e
m
d
.
e
T
a
h
s
u
e
r
i
t
e
n
g
m
p
c
y
l
e
i
r
a
n
d
t
u
e
r
r
e
o
o
n
f
t
o
t
h
e
t
h
e
w
a
s
o
t
e
i
r
l
s
a
n
h
a
d
l
l
be measured and recorded to 1 °C.
NOTE Distilled/de-ionized water (BS 1377-1:2016, ) should be used unless the material in-situ will be below
the water table, in which case water from the site should be used.
6. 1
13.5.4.5.2
13.5.4.5.3
13.5.4.5.4
The volume of water remaining in the measuring cylinder shall be recorded and shall be calculated by
difference of volume of water used.
The four (equally spaced) electrodes at the required test position shall be inserted, through pre‑drilled
clearance holes (if required), to a depth equivalent to the centre of the sample.
If it is not possible to insert an electrode due to the presence of a lithic fragment for example, the
electrode shall be moved to a new position where the equal spacing can be maintained.
NOTE Whilst it may be possible to move a single electrode and maintain the equal spacing required for this test,
it is likely that all electrodes will need to be moved to a new location.
13.5.4.5.5
The terminals on the outer "current" electrodes shall be connected to the current/output terminals of
the resistivity meter with the insulated copper wire. The terminals on the inner ‘potential’ electrodes
shall be connected to the potential/input terminals of the resistivity meter with the insulated
copper wire.
13.5.4.5.6
A suitable current, I (in A) shall be applied across the outer electrodes and the resulting resistance R,
(
i
n
Ω
)
b
e
t
w
e
e
n
t
h
e
i
n
n
e
r
e
l
e
c
t
r
o
d
e
s
r
e
c
o
r
d
e
d
.
NOTE The applied current should initially be set to the minimum current setting available on the measurement
device being used. This should be increased in single increments until a stable (repeatable) resistance is measured. A
current of about 10 mA is suitable for many soils.
13.5.4.5.7 13.5.4.5.6 shall be repeated to obtain 2 further repeat measurements (3 measurements in total).
13.5.4.5.8
The temperature of the soil sample and the ambient temperature of the laboratory facility in which the
measurements were undertaken, shall be undertaken to the nearest 1 °C immediately after the test.
13.5.4.5.9 13.5.4.5.7 to 13.5.4.5.8 shall be repeated after allowing the soil to stand for 1 h after saturation, and
topping up with water if necessary. The temperature of the water shall be measured and recorded to
the nearest 1 °C.
NOTE
Alternating current will cause a temperature rise if continued for a length of time.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 87
BS 1377‑3:2018
BRITISH STANDARD
13.5.4.5.10
The sample shall be removed from the test container and two specimens for the determination of
13.5.4.5.11
The electrodes and box shall be cleaned and dried before re‑use or storage.
water content, as described in BS EN ISO 17892‑1 shall be taken.
13.6 Calculations
13.6.1
For each measurement of resistance (except those conducted using the Wenner Array measurement),
the resistivity of the soil, rs
rs
=
(
i
n
Ω
m
)
s
h
a
l
l
b
e
c
a
l
c
u
l
a
t
e
f
d
r
o
m
t
h
e
e
q
u
a
t
i
o
n
:
RA
(63)
1000 L
where
R
A
L
13.6.1.1
i
s
t
h
e
m
e
a
s
u
r
e
d
r
e
s
i
s
t
a
n
c
e
b
e
t
w
e
e
n
t
h
e
p
o
t
e
n
t
i
a
l
e
l
e
c
t
r
o
d
e
s
(
i
n
Ω
)
;
is the cross‑sectional area of the soil chamber (in mm 2 );
is the length of the soil chamber between the potential electrodes (in mm).
NOTE Electrical resistivity is usually denoted by the symbol ρ s, but rs is used in this standard to avoid confusion
with soil particle density.
For each measurement of resistance using the Wenner Array, the average of three measured values of
the resistance, R
(
i
n
Ω
)
s
h
a
l
The resistivity of the soil, rs
rs
l
b
(
i
e
n
c
a
Ω
l
c
m
u
)
l
s
a
h
t
e
a
l
d
l
.
b
e
c
a
l
c
u
l
a
t
e
d
f
r
o
m
t
h
e
e
q
u
a
t
i
o
n
.
= Rs × G f
(64)
where
Rs
is the measured resistance;
Gf
is the measured geometric factor relating to the test container and the electrode
separation used.
13.6.1.2
NOTE Electrical resistivity is usually denoted by the symbol ρs, but rs is used in this standard to avoid confusion
with soil density.
If the test temperature T (in °C) was different from 20 °C, the equivalent resistivity at 20 °C, r20 , (in
Ω
m
r20
13.6.1.3
)
s
h
a
l
l
b
e
{
c
a
l
c
u
l
a
t
e
d
f
r
o
m
= rT 1 1 +  0 . 02 (T1 − 20 ) 
NOTE
t
h
e
m
e
a
s
u
r
e
d
r
e
s
i
s
t
i
v
i
t
y
,
}
RT1
(
i
n
Ω
m
)
,
f
r
o
m
t
h
e
e
q
u
a
t
i
o
n
:
(65)
This correction is valid only when the temperature T lies between 5 °C and 30 °C.
The bulk density of the soil sample ρ (in Mg/m 3 ) shall be calculated from its dimensions and mass.
The determination of water content for the representative sample shall be calculated using the
method as described in BS EN ISO 17892‑1.
13.6.1.4 For saturated open container test (13.4)
13.6.1.4.1
The volume of water contained in the two chambers behind the electrodes shall be calculated using
13.6.1.4.2
The volume of water required to saturate the soil shall be calculated by deducting the volume
the method in BS EN ISO 17892‑1.
calculated in
13.6.1.4.1 from the total volume of water added to saturate the soil.
88 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
13.6.1.4.3
BS 1377‑3:2018
The density of the soil sample
ρ (in Mg/m3 )
as compacted into the box, shall be calculated from its
dimensions and mass (see BS EN ISO 17892‑2).
13.7 Test report
The test report shall state that the test was carried out in accordance with the relevant parts of
BS 1377‑3 and shall contain the following information:
a)
the method of test used;
b
t
h
)
e
s
a
m
p
l
e
l
o
c
a
t
i
o
n
a
s
r
e
q
u
i
r
e
d
b
y
t
h
e
c
l
i
e
n
t
,
f
o
r
i
n
s
t
a
n
c
e
i
n
t
h
e
f
o
r
m
o
f
a
1
0
o
r
t
w
e
l
v
e
f
i
g
u
r
e
British National Grid reference and the depth from the ground surface;
c)
the drilling method and sampling tool as appropriate (see BS 5930 or BS EN ISO 22475‑1);
d)
for undisturbed samples the method of preservation;
e)
sample description to BS 5930;
NOTE 1 The corresponding depth of the top and bottom of undisturbed borehole samples should be recorded
where appropriate.
f)
the separation distance between potential electrodes used for each measurement undertaken;
NOTE 2 Any issues encountered inserting the potential electrodes should be noted, as well as cause (where
appropriate) and details of any remedial action taken or aborted measurements.
g)
the test temperature of both the soil sample and ambient temperature of the laboratory facility
in which the measurements were undertaken (in °C); and
h
)
t
h
e
c
a
l
c
u
l
a
t
e
d
r
e
s
i
s
t
i
v
i
t
y
f
o
r
e
a
c
h
m
e
a
s
u
r
e
m
e
n
t
u
n
d
e
r
t
a
k
e
n
,
t
o
t
w
o
s
i
g
n
i
f
i
c
a
n
t
f
i
g
u
r
e
s
,
c
o
r
r
e
c
t
e
d
to 20 °C if appropriate;
NOTE 3 In addition for the undisturbed cylindrical sample measurements, the calculated resistivity should be
accompanied by the position of the measurement along the sample corresponding to the mid-point between the
potential electrodes. For the partially saturated "open-container" measurements the type of sample should be
recorded (i.e. undisturbed or compacted sample). For the saturated “open-container” measurements, the resistivity
of the saturated soil sample initially, and after 1 h of saturation (in Ωm), to two significant figures, corrected to
20 °C if appropriate.
i
)
i
f
r
e
q
u
i
r
e
d
,
t
h
e
c
o
r
r
e
s
p
o
n
d
i
n
g
r
e
s
i
s
t
i
v
i
t
y
(
i
n
Ω
m
)
i
n
-
s
i
t
u
(
a
s
i
n
t
h
e
o
n
s
i
t
e
)
a
t
a
t
e
m
p
e
r
a
t
u
r
e
o
(in °C) is rT1 shall be calculated from:
rT 1 =
j)
r20
1 + [ 0 . 02( T1 − 20 )]
f
T1
(66)
for sieved/compacted samples, the following information shall also be recorded;
1)
the method of sample preparation (e.g. details of drying/crushing/sieving);
2)
details of sieving and the approximate percentage of large particles removed from the
original sample, if any;
3)
details of the actual compaction method (including mass/volume of sample used and
approximate compactive effort expended during the compaction process); and
4)
k)
the approximate water content and compaction density of the tested soil;
for undisturbed or compacted (partially saturated) soil samples, the water content of
representative intervals from undisturbed soil samples or at which a sample was compacted;
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 89
BS 1377‑3:2018
BRITISH STANDARD
l)
for the saturated “open‑container” measurements the following information should also
be recorded;
1)
the volume of water required to saturate the soil, both initially and the extra volume of
water required to re‑saturate the soil after 1 h; and
2)
the temperature of the water when added and soil temperature/ambient temperature
during any measurements undertaken; and
m) the information required by BS 1377‑1:2016,
10.1 .
14 Determination of the redox potential
14.1 General
14.1.1 Principle
The test described in this clause is for the determination of the redox potential of a sample of soil in
the laboratory.
The method used is to measure the electrochemical potential between a platinum electrode and a
saturated calomel reference electrode in contact with the soil.
NOTE
Other types of reference electrode are available and can be used instead.
The pH of the soil also has to be determined to enable the standardized redox potential to
be calculated.
14.1.2 Purpose
The redox potential provides a means of assessing whether a soil is conducive to the activity of
sulfate‑reducing bacteria, which cause corrosion of metals. These bacteria, which are present in most
s
o
i
l
s
,
f
l
o
u
r
i
s
h
u
n
d
e
r
r
e
d
u
c
i
n
g
c
o
n
d
i
t
i
o
n
s
(
l
o
w
r
e
d
o
x
p
o
t
e
n
t
i
a
l
)
a
n
d
b
e
c
o
m
e
d
o
r
m
a
n
t
u
n
d
e
r
o
x
i
d
i
s
i
n
g
conditions (high redox potential).
Changes in soil properties can cause enhanced corrosion where continuous buried metals, e.g. steel
pipelines, pass from one soil type to another.
14.1.3 Limitations
R
e
d
o
x
p
o
t
e
n
t
i
a
l
r
e
s
u
l
t
s
a
r
e
o
f
s
i
g
n
i
f
i
c
a
n
c
e
o
n
l
y
f
o
r
s
o
i
l
s
a
m
p
l
e
s
t
h
a
t
h
a
v
e
n
o
t
b
e
e
n
d
i
s
t
u
r
b
e
d
.
T
e
s
t
s
o
n
soil that has been remoulded or recompacted in the laboratory are of questionable value because of
the change in properties resulting from unavoidable exposure to the atmosphere. It is recommended
that whenever possible the redox of undisturbed samples is measured in‑situ at appropriate
intervals, as described in BS 1377‑9.
Results of these tests shall be interpreted by a specialist.
14.1.4 Type of sample
The undisturbed sample used for the test shall be obtained in a sampling tube from a borehole, or
prepared from a block sample taken from an open excavation, provided that it can be adequately
sealed to prevent atmospheric oxidation. Samples of coarse soil shall be taken in a non‑conducting
container which can be adequately sealed.
NOTE 1 Metal containers can cause changes in the redox value with time.
NOTE 2 Laboratory redox tests should be carried out immediately after sampling.
The requirements of BS 1377‑1, where appropriate, shall apply to this test method.
90 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
14.2 Apparatus
14.2.1
Rigid container, (referred to as the test container) of suitable non‑conducting material at least
100 mm across internally and 400 mm to 1 000 mm long.
NOTE 1 The sampling tube may be used if it is of suitable material.
14.2.2
NOTE 2 Rigid plastics piping of PVC or polypropylene have been found to be suitable.
Suitable means of extruding the undisturbed sample from the sampling tube and into the test container
(when the sample is not received in a suitable non‑conducting container), such as that referred to in
9.2.2 .
BS 1377‑1:2016,
14.2.3
Platinum probe, having two separate platinum electrodes embedded in the nosepiece, with a
means of protection when not in use. The probe is provided with a connecting lead permitting
the inclusion of each platinum electrode individually in an electric circuit, and each connection is
s
14.2.4
e
p
a
r
a
t
e
l
y
i
d
e
n
t
i
f
i
e
d
.
Calomel reference probe, having a mercury/mercurous chloride reference electrode which can be
r
e
f
i
l
l
e
d
a
n
d
w
i
t
h
a
c
o
n
n
e
c
t
i
o
n
t
o
a
c
e
r
a
m
i
c
j
u
n
c
t
i
o
n
.
T
h
e
c
a
l
o
m
e
l
r
e
f
e
r
e
n
c
e
e
l
e
c
t
r
o
d
e
s
h
a
l
l
b
e
k
e
p
t
clean when not in use by being stored in a sealed container. When not in use, precipitation of crystals
due to evaporation loss shall be prevented, particularly at the porous junction, by storing upright and
closing the breather hole, or by immersion in saturated potassium chloride solution.
14.2.5
NOTE
The platinum and calomel probes are often separate and made of glass and are therefore fragile.
Calibrated voltmeter, having a performance conforming to BS 89, class 2.5. The total measuring range
shall be 0 V d.c. to 2 V d.c. with a readability within 10 mV. The input impedance shall be not less than
10 6
Ω
a
n
d
t
h
e
p
o
l
a
r
i
t
y
(
p
o
s
i
t
i
v
e
o
r
n
e
g
a
t
i
v
e
)
s
h
a
l
l
b
e
m
a
r
k
e
d
o
n
t
h
e
t
w
o
i
n
p
u
t
t
e
r
m
i
n
a
l
s
.
The instrument shall be re‑calibrated at intervals not exceeding 12 months.
14.2.6
14.2.7
14.2.8
14.2.9
14.2.10
14.2.11
14.2.12
Insulated flexible electric cable and connectors, for use with the probes.
Apparatus for measuring the pH value of soil, as described in 12.3 .
Thermometer, readable to 1 °C.
Apparatus for the determination of water content, as described in BS EN ISO 17892‑1.
Sample trimming tools, e.g. trimming knife, spatula, end‑trimming tool.
Paper tissues.
Absorbent surgical cotton-wool swabs.
14.3 Reagents
14.3.1
Potassium chloride, saturated solution contained in a screw‑topped plastics bottle with a pouring lip,
s
u
i
t
a
b
l
e
f
o
r
f
i
l
l
i
n
g
t
h
e
r
e
s
e
r
v
o
i
r
o
f
t
h
e
c
a
l
o
m
e
l
r
e
f
e
r
e
n
c
e
p
r
o
b
e
,
o
r
w
i
t
h
a
s
e
p
a
r
a
t
e
s
m
a
l
l
d
r
o
p
p
e
r
o
r
syringe. 500 ml is a suitable quantity.
14.3.2
14.3.3
Jeweller’s rouge.
Colourless methylated spirit, about 70% strength with 30% distilled/de‑ionized water (BS 1377‑
6.1 ) water, in a screw‑topped wide‑mouth bottle. 500 ml is a suitable quantity.
14.3.4 Distilled/de-ionized water (BS 1377‑1:2016, 6.1 ), in two differently marked wash bottles, for cleaning
1:2016,
platinum electrodes. 500 ml is a suitable quantity for each bottle.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 91
BS 1377‑3:2018
BRITISH STANDARD
14.4 Procedure
14.4.1 Preparation of sample
14.4.1.1
For an undisturbed sample taken in a non‑conducting container the test shall be undertaken in
the same container. Otherwise the sample shall be extruded and placed in a container of suitable
non‑conducting material for the test with the minimum of exposure to air.
14.4.1.2
A block or lump sample shall be wrapped tightly in polythene sheet immediately after taking from the
ground and need not be transferred to another container.
14.4.1.3 The sample shall be tested within 2 days of sampling. Exposure to air shall be kept to a minimum.
14.4.2 Preparation of probes
14.4.2.1 The probes shall be kept upright to prevent leakage of the solution.
14.4.2.2 The calomel reference probe shall be assembled in accordance with the operating instructions,
ensuring that the unit is full of a saturated solution of potassium chloride and that the solution
moistens the porous plug.
14.4.2.3
Air bubbles in the potassium choride solution shall be removed by gently tapping the probe, and
e
14.4.2.4
14.4.2.5
14.4.2.6
x
c
e
s
s
f
l
u
i
d
f
r
o
m
t
h
e
p
o
r
o
u
s
p
l
u
g
.
The platinum electrodes shall be cleaned and polished as necessary by using a smear of moist
jeweller’s rouge and gently polishing the electrode with cotton‑wool swabs.
The platinum electrode shall be washed, using the 70% methylated spirit.
Then, shall be washed thoroughly with distilled/de‑ionized water (BS 1377‑1:2016,
6.1 ).
NOTE The electrodes are washed by dipping into first one and then the other bottle of distilled de-ionized water
(BS 1377-1:2016, ). The different markings on the bottles help ensure that the same sequence is always followed.
/
6. 1
14.4.2.7
14.4.2.8
14.4.2.9
Each electrode shall be dried with clean paper tissues.
The probes shall be assembled ready for insertion into the soil sample.
The cable shall be connected from the positive terminal of the voltmeter to one of the platinum
electrodes and the cable from the negative terminals to the calomel reference electrode, but leave the
circuit open. This circuit is considered to give positive readings.
14.4.3 Measurement of redox potential
14.4.3.1 The probes shall be inserted into the soil sample about 100 mm apart. The platinum probe shall
penetrate to a depth of at least 50 mm.
14.4.3.2
14.4.3.3
14.4.3.4
The platinum probe shall be rotated by about a quarter up to one turn without allowing air to reach
the probes to ensure good contact with the soil.
The electric circuit shall be closed. The voltage and polarity (positive or negative) shall be recorded
when the voltage is steady.
NOTE Occasionally the current between the platinum electrode and the reference electrode will be in the reverse
direction such as to require the connections to the millivoltmeter to be reversed. In this case the reading should be
considered to be negative.
The connection from the positive terminal of the voltmeter shall be transferred to the other
platinum electrode.
14.4.3.5 14.4.3.2 and 14.4.3.3 shall be repeated.
14.4.3.6 If the two readings differ by more than 20 mV the probes shall be removed, the platinum electrodes
re‑cleaned and re‑installed in a different position at least 50 mm away, or at the other end, pushing
92 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
BRITISH STANDARD
BS 1377‑3:2018
the probes further into the soil if possible. The electrodes shall not be re‑installed in the original
positions as oxygen will have penetrated and a false reading could result.
14.4.3.7 14.4.3.2 to 14.4.3.5 shall be repeated. If the two readings again differ by more than 20 mV and there
is not enough length of sample for another repeat test, the sample shall be rejected, the electrodes
f
f
f
f
f
14.4.3.6.
14.4.3.8 The probes shall be removed, the electrodes cleaned as described in 14.4.2.4 to 14.4.2.7 and stored
as described in 14.2.4 .
14.4.3.9 The temperature of the soil shall be recorded to the nearest 1 °C.
14.4.3.10 A sample of the soil shall be taken from the zone of the test and place it in a sealed container.
c
l
e
a
n
e
d
a
n
d
t
h
e
t
e
s
t
p
e
r
o
r
m
e
d
o
n
a
n
o
t
h
e
r
s
a
m
p
l
e
o
t
h
e
s
a
m
e
s
o
i
l
.
I
t
h
e
r
e
i
s
a
s
u
f
i
c
i
e
n
t
l
e
n
g
t
h
o
sample, a further set of readings shall be taken, as described in
14.4.3.11
14.4.3.12
NOTE If a sample is required for microbiological examination the container should have been cleaned
and sterilized beforehand and should be of about 500 ml capacity. Fill the container completely to minimize
the air voids.
A portion of the sample shall be used for the determination of water content, as described in
BS EN ISO 17892‑1.
The pH of the sample shall be determined in accordance with the procedure described in
14.5 Calculations
12.5 .
The mean of the acceptable voltage readings shall be calculated and this value recorded (positive or
negative) as the potential of the platinum probe Ep to the nearest 10 mV.
Calculate the redox potential, Eh (in mV), from the equation:
Eh = Ep
+
2
5
0
+
6
0
(
p
H
–
7
)
(
6
6
)
where
Ep
is as observed above, and might be a positive or negative value;
pH
is the pH value of the aqueous suspension of soil determined in accordance with
12.5
The constant 250 is the correction factor for a calomel reference probe for converting the
measurement to that of a standard hydrogen electrode.
NOTE
For other types of reference probe, different constants are required (see BS 1377-9:1990,
5. 2. 1
).
14.6 Test report
The test report shall state that the test was carried out in accordance with BS 1377‑3:2018,
Clause 14 , and shall contain the following information:
a)
the method of test used;
b)
the mean value of the potential (in mV) of the two platinum probes, to the nearest 10 mV;
c)
the redox potential (in mV) to the nearest 10 mV;
d)
the pH value of the soil suspension;
e)
the type of reference probe;
f)
the type and approximate size of the sample;
g)
the temperature of the sample at the time of test; and
h)
The information required by BS 1377‑1:2016,
10.1 .
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 93
BS 1377‑3:2018
BRITISH STANDARD
Annex A (informative)
Determination of sulfur compounds
A.1 Background
Sulfur compounds are widely distributed in soils, rocks and recycled and secondary materials such as
a
s
h
e
s
a
n
d
s
l
a
g
s
.
T
h
e
m
o
s
t
c
o
m
m
o
f
n
o
r
m
s
a
r
e
s
u
l
f
a
t
e
a
n
d
s
u
l
f
i
d
e
Clause 7 describes the test methods
.
to be used for different sulfur compounds in soils, extremely weak and very weak rocks for assessing
their potential impact on civil engineering works. This includes some applications covered by the
S
p
e
c
i
f
i
c
a
t
i
o
n
f
o
r
H
i
g
h
w
a
y
W
o
r
k
s
S
e
r
i
e
s
6
0
0
[
5
]
a
s
f
i
l
l
.
S
o
m
e
o
f
t
h
e
t
e
s
t
s
a
r
e
a
l
s
o
s
u
i
t
a
b
l
f
e
o
r
u
s
e
o
n
samples of groundwater or surface water.
NOTE 1 For potential land contamination management, procedures should be in accordance with guidance from
the Environment Agency, Scottish Environmental Protection Agency, Environmental Agency Wales and Northern
Ireland Environmental Agency. Guidance on the ground investigation of potentially contaminated sites is given
in BS 10175.
Sulfur compounds present in a material are assessed for civil engineering purposes for the following
reasons as they can cause:
•
deterioration of buried concrete;
•
corrosion of metallic structural items;
•
h
•
deterioration of lime stabilized soils;
•
clogging of drains; and
•
pollution of surface waters and iron‑ and sulfate‑rich runoff that are often acidic.
e
a
v
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o
f
f
l
o
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r
s
l
a
b
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p
a
v
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m
e
n
t
s
a
n
d
e
a
r
t
h
w
o
r
k
s
;
Many of the above effects are due to the change in the form of sulfur, particularly the oxidation of
s
u
L
S
i
l
f
i
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p
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d
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t
i
c
i
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r
.
K
5] , BRE SD1 (BRE 2005) [1]
and BRE Digest 522 [9] .
NOTE 2 Further details can be found in a number of references including Czerewko et al. (2016) [7], TRL 447:2005
[2] and BRE SD1:2005 [1 ].
The distribution and concentration of sulfur compounds can be locally variable. The sampling
regime, including the number of samples taken and assessment of the variation, will depend on the
requirements of the project. However, the detrimental effects due to sulfur compounds are most
likely to be where the concentrations are the highest. Guidance on the number of samples to be taken
and the calculation of characteristic values for comparison with limiting values is given in guidance
such as TRL 447:2005 (TRL 2005) [2] and BRE SD1:2005 (BRE 2005) [1
Highway Works Series 600 (Highways England, 2016) [5] .
94 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
]
a
n
d
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p
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r
BRITISH STANDARD
BS 1377‑3:2018
A.2 Test methods for testing sulfur compounds not covered in this standard
A.2.1 General
A number of methods can be used to provide mineralogical information if required (see Czerewko et
al. 2003 [6] and 2016 [7] ).
•
x‑ray Diffraction (XRD);
•
scanning electron microscopy (SEM) with element analysis apparatus, such as energy dispersive
x‑ray spectroscopy (EDX);
•
r
e
•
l
a
f
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x
i
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n
.
A.2.2 X-ray diffraction
X
-
r
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m
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a
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e
.
D
e
t
e
c
t
i
o
n
l
i
m
i
t
s
depend on the crystallinity of the mineral and the content of the matrix but are generally less than
1% for amorphous minerals and less than 0.5% for more crystalline minerals.
A.2.3 Scanning electron microscopy
Scanning electron microscopy allows detailed examination of the structure of a material. Minerals can
b
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d
b
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f
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d
u
s
i
n
g
energy dispersive x‑ray spectroscopy (EDX), which are often a part of SEM apparatus.
A.2.4 Transmitted and reflected light microscopy
Framboids (extremely small pyrite crystals) often a few micrometres across can be distinguished
u
a
s
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d
g
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o
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.
A
d
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r
m
v
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a
d
y
also be studied.
A.2.5 Laboratory tests for susceptibility of sulfides to oxidation
T
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M
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d
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u
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s
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m
2
i
n
e
r
a
l
s
(
F
e
S
)
,
s
u
c
h
a
s
7.9 . The total reduced sulfur content,
7.11 , which can be used to give a
i
are not extracted by the hydrochloric acid used in the test in
i
e
7.11 . However, they normally form only a
w
a
pyrrhotite, can be determined by the test described in
s
i
s
i
u
n
l
g
f
i
d
t
e
e
s
s
(
F
e
S
)
s
u
c
h
a
s
p
y
r
i
t
e
.
D
i
s
u
l
f
i
d
e
s
t
measure of the total amount of potentially reactive sulfate in the material. The parameter oxidisable
s
u
l
f
i
d
e
(
O
S
)
i
s
b
a
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e
d
o
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t
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a
s
s
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a
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w
i
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o
x
i
d
i
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r
a
p
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d
l
y
.
T
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i
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i
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c
o
n
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e
r
v
a
t
i
v
e
and can lead to materials that are known to have performed satisfactorily being excluded from certain
applications because of high OS values.
T
h
e
•
s
i
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n
s
c
e
v
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r
p
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a
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r
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r
p
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c
f
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c
u
s
d
u
i
n
r
f
g
a
:
c
e
a
r
e
a
,
and the slower it will be to oxidise (pyrite that is visible to the naked eye will usually not be
problematical);
•
T
c
h
e
r
m
y
s
o
s
t
a
t
l
r
e
f
o
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r
a
s
l
t
e
(
r
s
s
)
o
a
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d
r
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b
p
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r
s
m
.
e
T
a
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i
a
S
l
;
E
M
a
s
w
e
l
l
a
s
s
o
m
e
optical microscopy methods.
For further methods see Reid and Avery (2009) [8] .
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 95
BS 1377‑3:2018
BRITISH STANDARD
A.3 Nomenclature and relations between test parameters (see Czerewko et
al. 2016 [7 ])
The water‑soluble sulfate content of groundwater is designated GWS and is reported as mg/l SO 4;
The water‑soluble sulfate content of soil is designated WS and is reported as mg/l SO 4;
The acid‑soluble sulfate content is designated AS and is reported as % SO 4;
The total sulfur content is designated TS and is reported as % S;
T
h
e
t
o
T
h
e
a
t
a
c
i
l
d
s
-
s
u
o
l
l
f
i
u
d
b
e
l
c
e
o
s
n
u
l
t
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f
i
n
d
t
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i
c
s
o
d
n
e
s
t
e
i
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n
t
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d
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t
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s
i
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t
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a
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s
d
u
t
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e
d
m
o
s
n
u
o
l
f
u
s
u
r
,
l
f
i
T
d
R
S
e
s
a
u
l
n
d
f
u
i
r
,
s
r
M
e
S
p
a
o
n
r
t
e
d
i
d
s
a
r
s
e
p
%
o
r
S
;
t
e
d
a
s
%
S
.
The designated parameters are used in setting limiting values or boundaries of classes for potential
f
5] and
guidance documents such as BRE SD1:2005 [1] .
h
a
r
m
t
o
c
o
n
c
r
e
t
e
a
n
d
s
t
e
e
l
i
n
s
p
e
c
i
f
i
c
a
t
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o
n
s
s
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a
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U
f
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S
f
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H
i
g
h
w
a
y
W
o
r
k
s
[
extraction procedure (see 7.3.2 ). The limits given for the materials classes are set to give guidance
based on the values given by this extraction procedure (BRE SD1 2005 [1] ; Highways England 2016
[5] ). WS might be less than the total sulfate in a material where the extraction solution reaches
saturation in sulfate, leaving some sulfate undissolved in the sample.
W
S
i
s
a
n
i
n
d
e
x
p
a
r
a
m
e
t
e
r
a
n
d
r
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a
m
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s
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l
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e
d
u
s
i
n
g
t
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s
p
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c
i
f
i
e
d
Sulfate is always expressed as SO 4 in solid and water samples. However, where SO 3 , as was usually
done following guidance documents issued prior to BRE Report BR 279 [3] , the conversion to SO 4 is:
shown below:
SO 4 (%) = 1 . 2 × SO 3 (%)
(A.1)
SO 3 (%) = SO 4 (%) ÷ 1 . 2
(A.2)
The same correction factors apply if the results are expressed as mg/l. If WS results are expressed as
g/l, they can be converted to mg/l as follows:
(
)
(
)
SO 4 mg/l =SO 4 mg/l ×1000
(A.3)
In other standards, such as BS EN 1744‑1, WS is reported as % SO 4 or mg/kg SO 4. These values can
be converted to mg/l SO 4 using the equations below provided WS is determined on a 2:1 water:
solid extract.
(
)
SO 4 (%)=  SO 4 mg/l  ÷5000
(
)
(A.4)
SO 4 mg/l =5000×SO 4 %
( )
(A.5)
mg/l SO 4 =0.5×mg/kg SO 4 (per kg of dry sample)
(A.6)
In the determination of GWS, WS and AS using ICP‑AES or similar methods, the sulfur content of the
extract is determined directly and the sulfate content is calculated as shown below:
(
)
SO 4 mg/l =3×S(mg)
96 © THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED
(A.7)
BRITISH STANDARD
BS 1377‑3:2018
(A.8)
SO 4 (%)=3×S ( % )
In the determination of TS the following equation can be applied to the TS value to obtain the amount
of sulfate that would be present if all the sulfur in the sample was present as sulfate. This is termed
the Total Potential Sulfate (TPS):
(A.9)
TPS ( %SO 4 ) =3×TS ( %S )
In some materials, such as evaporite sediments or ashes, all the sulfur may be present as sulfate.
H
o
v
a
t
h
w
e
r
y
i
e
v
e
n
O
x
g
i
r
,
a
d
i
i
n
m
z
m
o
a
b
u
l
o
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e
s
t
t
s
S
n
.
u
a
T
l
t
u
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f
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e
d
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r
a
a
s
l
m
m
(
o
O
a
u
S
t
e
n
)
t
a
r
i
o
n
a
f
d
l
s
c
s
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a
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l
u
f
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n
l
f
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t
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b
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o
a
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c
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a
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d
d
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b
d
i
a
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r
g
r
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r
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r
a
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t
e
m
n
d
t
i
T
b
f
o
a
R
S
l
t
h
l
a
t
h
s
e
s
s
u
u
l
l
f
a
f
i
t
e
d
e
s
a
o
x
n
i
d
d
i
s
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u
e
l
d
f
i
i
d
s
e
s
t
e
i
r
n
m
e
d
:
(A.10)
OS ( %SO 4 ) =3×TRS ( %S )
The OS represents a source of sulfate that would not be detected if only AS was measured. OS can also
be estimated from the difference between TPS and AS:
(A.11)
OS ( %SO 4 ) =TPS ( %SO 4 ) - AS ( %SO 4 )
Measurement of the different parameters allows a number of “sense checks” to be carried out on the
results. If the values are correct, then:
•
AS (% SO 4
•
TPS (% SO 4
•
TPS (% SO 4
•
TPS (% SO 4
•
TPS (% SO 4
•
T
S
(
%
S
)
w
i
l
l
a
l
w
a
y
s
b
e
≥
T
•
T
S
(
%
S
)
w
i
l
l
a
l
w
a
y
s
b
e
≥
M
•
T
R
S
(
%
S
)
)
w
i
l
l
a
l
w
a
y
s
b
e
≥
W
S
(
)
w
i
l
l
a
l
w
a
y
s
b
e
≥
W
S
)
w
i
l
l
a
l
w
a
y
s
b
e
≥
A
S
)
w
i
l
l
a
l
w
a
y
s
b
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When making the sense checks, allowance should be made for the accuracy and precision of the test
methods, particularly where indirectly determined parameters (TPS, OS) are involved, and for the
variability of distribution of sulfur compounds in most materials. However, breaches of the sense
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parameters. These should be investigated and the tests repeated until the results conform to the
sense checks.
© THE BRITISH STANDARDS INSTITUTION 2018 – ALL RIGHTS RESERVED 97
BS 1377‑3:2018
BRITISH STANDARD
Bibliography
Standards publications
For dated references, only the edition cited applies. For undated references, the latest edition of the
referenced document (including any amendments) applies.
BS 1377‑4, Methods of test for soils for civil engineering purposes — Part 4: Compaction-related tests
BS 1377‑9, Methods of test for soils for civil engineering purposes — Part 9: In-situ tests
BS 1752, Specification for laboratory sintered or fritted filters including porosity grading
BS 10175, Investigation of potentially contaminated sites — Code of practice
BS EN 1744‑1, Tests for chemical properties of aggregates — Part 1: Chemical analysis
BS EN 1997‑2, Eurocode 7 — Geotechnical design — Part 2: Ground investigation and testing
BS EN ISO 11885, Water quality — Determination of selected elements by inductively coupled plasma
optical emission spectrometry (ICP-OES)
BS EN ISO 17892‑2, Geotechnical investigation and testing — Laboratory testing of soil — Part 2:
Determination of bulk density
BS EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
PD ISO Guide 30, Reference materials — Selected terms and definitions
Other publications
[1]
BRE Special Digest. 2005, Concrete in aggressive ground (third edition). SD1 [IHS BRE Press,
Willoughby Road, Bracknell, Berkshire, UK] .
[2]
TRL 447. 2005. Sulfate specification for structural backfills. TRL Limited, Wokingham,
Berkshire, UK.
[3]
BOWLEY M. J., 1995. BRE Report 279: Sulphate and acid attack on concrete in the ground:
recommended procedures for soil analysis. IHS BRE Press, Willoughby Road, Bracknell,
Berkshire, UK.
[4]
WEAST R.C., ed. CRC Handbook of Chemistry and Physics. 55 Edition, 1974, pp. D224–5.
[
5
]
H
I
G
H
W
A
Y
S
E
N
G
L
A
N
D
.
2
0
1
6
.
S
p
e
c
i
f
i
c
a
t
i
o
n
f
o
r
h
i
g
h
w
a
y
w
o
r
k
s
.
V
o
l
u
m
e
1
–
S
e
r
i
e
s
6
0
0
Earthworks, Manual of contract documents of highway works.
[6]
[7]
[8]
CZEREWKO M.A., CRIPPS J.C., REID J.M., DUFFELL C.G. Sulfur species in geological materials
sources and quantification . Cement Concr. Compos. 2003, 25 pp. 657–671.
CZEREWKO M.A., LONGWORTH I., REID J.M., CRIPPS J.C. Standardised terminology and test
methods for sulphur mineral phases for the assessment of construction materials and aggressive
ground. Q. J. Eng. Geol. Hydrogeol. 2016, 49 pp. 245–265. DOI:10.1144/qjegh2016‑010.
REID J.M., AVERY K. 2009. Measuring the potential reactivity of sulphides in aggregates. TRL
Report MA/7/G/5/001. TRL Limited, Wokingham, Berkshire, UK.
[9]
BRE Digest DG 522 . 2011, Hardcore for supporting ground floors of buildings. IHS BRE Press,
Willoughby Road, Bracknell, Berkshire, UK.
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