Corrosivity of Soils/Groundwater –
Testing for construction purposes
Soils which come into contact with construction materials may be corrosive, either to concrete or reinforcing
steel, leading to failure of the structure or necessitating special design considerations.
There are a variety of tests which may be carried out for soil corrosivity., and there are a number of different
Standard Methods which may be used, see list at the end of this Technical Note.
Because of the many possible different test methods, based on Standards from different parts of the world,
Hill Laboratories is offering only a limited number of tests for each analyte. The test methods we have
selected are either the ones found in NZ Standard requirements (eg NZS 3101), or ones which has most
commonly been requested by our clients.
The methods tend to be very labour intensive, and often include ‘difficult’ preparation steps such as filtering
large volumes of solution in which a finely ground soil has been suspended in an extracting solution – which
does not happen quickly or easily, so necessitates at least overnight settling of samples before filtration or
centrifugation. This means it is not possible to process these analyses under Urgent or High Priority.
Results are usually compared (by the client) to a suitable reference eg NZS 3101: Part 1 2006
New Zealand Accredited Laboratory
Controlled Document: CT.Env.XX [TECHNOTE/Corrosivity of Soils]
Member of the New Zealand Association of Consulting Laboratories
Version: Draft, Issue Date 9/1/12
Issuing Officer: P G Robinson
Hill Labs Methods – Soils
Sample preparation
Test
Drysieve
Sieve425um
Description
Air dry at 35C in a forced air oven, pass through a 2mm
sieve
Pass the above dried sample through a 425um sieve
Synthetic Precipitation
Leaching Procedure
Physical tests
Test
pH
Cation Exchange
Capacity
Method Ref
USEPA 1312
Chemical tests
Test
ANC
NAPP
MPA
Description
ANC = Acid Neutralising Capacity
NAPP = Nett Acid Production Potential
MPA = Maximum Potential Acidity
Carbonate (High
Sample is air-dried, 2mm sieved. Further ground to sub-425um.
level
5g + 100mL 1M HCl, stand 1hr, titrate 25mL with 1M NaOH
titrimetric method)
using screened methyl orange indicator.
Chloride
Sample is air-dried, 2mm sieved. Further ground to sub90um.10g + 200mL DI water, boiled 15 min with stirring.
Settled, then an aliquot taken for potentiometric titration with
silver nitrate. DL 50mg/kg dry wt.
New Zealand Accredited Laboratory
Version: Draft, Issue Date 9/1/12
Method Ref
Code
pHBS137
7
Code
ANC
NAPP
MPA
BS 1377:Part 3:1990 section 6.3
DIN 4030 Part 2, 1991 section 5.3.5
Issuing Officer: P G Robinson
Member of the New Zealand Association of Consulting Laboratories
Price
SPLP
[NOTE: The commonest tests are shown in blue, bold, italic]
Description
Method Ref
Sample is air-dried, 2mm sieved. 30 g sample + 75mL DI water [BS 1377:Part 3:1990 section 9.5]
(1:2.5 w:v), mixed, stand at least 8hr. Potentiometric
measurement of pH.
Controlled Document: CT.Env.XX [TECHNOTE/Corrosivity of Soils]
Code
ClDin4030
Price
Price
Acid soluble
sulphate
Water soluble
sulphate
Water soluble
sulphate
Organic matter
Baumann Gully
Acidity
Sample is air-dried, 2mm sieved. Further ground to sub425um. 2G + 200mL 10% HCl, boil gently 4-5min. Add
bromine solution, then ammonium hydroxide. Precipitate as
BaSO4. Gravimetric determination. DL 0.1g/100g dry wt
Sample is air-dried, 2mm sieved. Further ground to sub-425um.
50g:50mL DI water, ?16hrs, settle, filter or centrifuge. Add
bromine solution, then ammonium hydroxide. Precipitate as
BaSO4. Gravimetric determination. DL 0.1g/100g dry wt
Sample is air-dried, 2mm sieved. Further ground to sub425um. 50g:100mL DI water, 16hrs, settle, filter or centrifuge.
Gravimetric as barium sulphate.
NZS 4402:1986 Part 3, Test 3.2
NZS 4402:1986 Part 3, Test 3.2 (Note
1 in NZS)
BS 1377:Part 3:1990 sections 5.3.3,
5.5
NB: Requires reporting as “SO3”
!!!!
Walkley Black Oxidation (Dichromate oxidation) has
interferences from sulphides or chlorides. Mass Loss on Ignition
may have positive interferences from some non-organic sources
[BS 1377:Part 3: 1990.
Hill Laboratories has substituted TOC (Total Organic Carbon),
with a calculation to Organic Matter = TPC x 1.72 [Ref???] as
being a more reliable indicator of Organic Content
Sample is air-dried, 2mm sieved. 100g extracted with200mL 1M DIN 4030 Part 2, 1991 section 5.3.2
(modified for <2mm rather than
sodium acetate for 1hr. This produces acetic acid which is
<90um sample)
titrated with standard NaOH using phenolphthalein indicator
DL 5mL 0.01M NaOH/kg dry wt
Controlled Document: CT.Env.XX [TECHNOTE/Corrosivity of Soils]
New Zealand Accredited Laboratory
Version: Draft, Issue Date 9/1/12
SO4Tnzs4402
Issuing Officer: P G Robinson
Member of the New Zealand Association of Consulting Laboratories
SO4WSbs1377
BGAcidity
Hill Labs Methods - Groundwaters
Physical tests
Test
pH
EC
Description
Hydrogen ion concentration, indicator of acidity/basicity
Electrical conductivity. Related to dissolved ions eg saltwater
Chemical tests
Test
Filtration for Cl, SO4
Chloride
Sulphate
Filtration for Dissolved
Metals
Dissolved magnesium
Description
Method Ref
Code
Price
Method Ref
Code
Filtmg
Cl
SO4
Filtm
Price
(If not Field Filtered)
0.45um filtered sample, ICPMS
Controlled Document: CT.Env.XX [TECHNOTE/Corrosivity of Soils]
New Zealand Accredited Laboratory
Version: Draft, Issue Date 9/1/12
Mgdt
ICPmin
Issuing Officer: P G Robinson
Member of the New Zealand Association of Consulting Laboratories
Relevant Standards
BS1377: Part 3: 1990 5.3.2.2 – 5.3.2.4 [Requires air drying, then sieving through 425um sieve]
“Methods of test for Soils for civil engineering purposes. Part 3. Chemical and electro-chemical tests”
DIN 4030 Part 2, June 1991 “Assessment of water, soil and gases for their aggressiveness to concrete.
Collection and examination of water samples”
NZS 3101.1&2:2006
Concrete structures standard - Concrete Structures Standard
NZS 4202 Part 3 1986
BS 8500 (and European Standard BS EN 206-1) “Concrete”, which links with BRE Special Digest 1
BRE Special Digest 1 “Concrete in aggressive ground” [UK Building Research Establishment Ltd,
www.bre.co.uk]
Other references
Acid soluble chlorides in concrete
• ASTM C1152
• AS1012.20
• BS1881:124
Acid soluble chlorides in aggregate
• AS 1012.20
Water soluble chlorides in aggregate
• ASTM C1218
• BS EN 1744
Acid soluble sulphates in concrete
• AS 1012.20
• BS1881:124
Acid soluble sulphates in aggregate
• AS 1012.20
• BS EN 1744
Water soluble sulphates in aggregate
• BS EN 1744
New Zealand Accredited Laboratory
Controlled Document: CT.Env.XX [TECHNOTE/Corrosivity of Soils]
Member of the New Zealand Association of Consulting Laboratories
Version: Draft, Issue Date 9/1/12
Issuing Officer: P G Robinson