CHAPTER 3
MATERIALS AND TESTING
3.1
Introduction
Upon completion of compaction at site, the In Situ Field Density Test is
required to carry out with the appropriate apparatus, materials and unusual
expertise. The methods of testing should be as stipulated in the specifications.
Normally they will be methods specified in Malaysian Standards, or
internationally recognized standard methods of testing specified by agencies such
as the British Standards Institution, The American Association of State Highway
and Transportation Officials (ASSSHTO), the American Society for Testing and
Materials (ASTM), ETC. All test results should be recorded on standard forms
especially prepared for the purpose. Work performed in relatively low levels of
inspection, should be subjected to more intensive testing. Below are the stages
involving the whole process of the research project as shown in Figure 3.1.
18
STAGE I :
Preparation of the materials and apparatus:
1.
Assemble all the necessary equipment and apparatus needed.
2.
Preparation of standard sand and river sand.
3.
Prepare form sheets.
4.
Carry out soil classification tests and laboratory compaction test on
The filled material.
STAGE II :
Calibration of the standard and river sand:
1.
Oven dried and stored for 7 days the prepared sand.
2.
Determine the mass of sand in the cone of the pouring cylinder.
3.
Determine the bulk density of the sand.
4.
Calculate the bulk density of the sand.
STAGE III :
Conduct the test at site:
1.
Locate the site.
2.
Carry out 2 series of test for standard sand and 3 series of test for
river sand at various types of compacted sites and soils.
3.
Collect data.
STAGE 4 :
Analyze the collected data:
1.
Calculation for the field density.
2.
Interpretation and comparison of the result.
3.
Establish the correlation factor between standard sand and river
Sand.
Figure 3.1: Flow chart of the research procedures.
19
3.2
Apparatus and Equipment
The apparatus to use for the laboratory testing and In-Situ Field Density
test are:
i.
Small pouring cylinder, as shown in figure 3.1.
ii.
A bent spoon dibber and a scraper tool.
iii.
Cylinder, metal, calibration container, with an internal diameter of 100 +
2 mm and an internal depth of 150 + 3mm fitted with a lip 50mm wide
and about 5mm thick surrounding the open end.
iv.
Balance, readable to 1 g.
v.
Glass plate of at least 10mm thick and about 500mm square.
vi.
Metal tray or container to take excavated soil about 300mm in diameter
and about 40mm deep.
vii.
Apparatus for moisture content determination as specified in BS1377:
Part2: 1990.
viii.
Material. The replacement sand shall be:
a)
Clean closely graded silica sand and
b)
River sand as prepared.
ix.
Apparatus for particle density test as specified in BS1377 Part 2 : Test 8.3
using Small Pyknometer Method (Density Bottles).
x.
Apparatus for the determination of liquid limit as specified in BS1377
Part 2 : Test 4.3 using Cone Penetrometer Method (definitive method).
xi.
Apparatus for determination of the plastic limit and plasticity index
BS1377 Part 2 :Test 5.3 and Test 5.4.
xii.
Apparatus for determination of particle size distribution :AASHTO
T87-70 & T88-70 or ASTM D421-58 7 D422-63.
xiii.
Apparatus for determination of laboratory compaction test BS1377 Part 4 :
Test 3.5.
20
3.3
The Testing Procedures
The test will be carried out accordance with BS1377: 1990 or AASHTO
or ASTM. Descriptions of test methods have been broken down into smaller
procedural stages. Only the relevant test methods will be discussed.
3.3.1
Determination Of Moisture Content (Oven-drying method)
Water is present in most naturally occurring soils. The amount of water,
expressed as a pro portion by mass of the dry solid particles, known as the
moisture content, has a profound on soil behavior.
Moisture content is required as a guide to classification of natural soil. It
is also acted as a control criterion in re-compact soil and is measured on samples
used for most field and laboratory tests. The oven-drying method is the definitive
procedure used in standard laboratory practice. This method covers the
determination of the moisture content of a specimen of soil as a percentage of its
dry mass.
The test method is accordance with BS 1377 : Part 2 : 1900 : Method 3.2
(Oven-drying method).
3.3.2
Determination Of Particle Density
There are three methods can be used. The first is a gas jar method suitable
for most soils including those containing gravel-sized particles. The second is the
21
small pyknometer method which is the definitive method for soils consisting of
clay, silt and
22
sand-sized particles. The third method is a pyknometer method, suitable for soils
containing particles up to medium gravel size.
Small pyknometer method is suitable for soils consisting of particles finer
than 2 mm. Larger may be ground down to smaller than this size before testing.
At least two specimens shall be oven dried at 105 0C to 110 0C, and then stored in
airtight containers until required.
The test method is accordance with BS 1377 : Part 2 : 1900 : Method 8.3
(Small pyknometer method).
3.3.3
Determination Of The Liquid Limit
The liquid limit is the empirically moisture content at which a soil passes
from the liquid state to the plastic state. It provides a means of classifying a soil,
especially when the plastic limit is also known.
Two main types of test are specified. The first is the cone penetrometer
method, which is fundamentally more satisfactory than the alternative because it
is essentially a static test depending on soil shear strength. It is also easier to
perform and gives more reproducible results. The second is the much earlier
Casagrande type of test. This test introduces dynamic effects and is more
susceptible to discrepancies between operators.
Cone penetrometer method covers the determination of the liquid limit of
a sample of soil in its natural state, or of a sample of soil from which material
retained on a 0.425mm test sieve has been removed.
The test method is accordance with BS 1377 : Part 2 : 1900 : Method 4.3
(Cone penetrometer method).
23
3.3.4
Determination Of The Plastic Limit And Plasticity index
The plastic limit is the empirically established moisture content at which
a soil becomes too dry to be plastic. It is used together with the liquid limit for
determine the plasticity index which when plotted against the liquid limit on the
plasticity chart provides a means of classifying cohesive soils. It is convenient to
carry out the test on a portion of the material prepared for one of the liquid limit
test procedures.
Method for plastic limit covers the determination of the plastic limit of a
soil sample, i.e. the lowest moisture content at which the soil is plastic. The
sample shall be of soil in its natural state, or of soil from which material retained
on a 0.425mm test sieve has been removed.
The test method is accordance with BS 1377 : Part 2 : 1900 : Method 5.3
(Method for plastic limit).
3.3.5
Determination Of Particle Size Distribution
Two methods of sieving are specified. Wet sieving is the definitive
method applicable to essentially cohesion-less soils. Dry sieving is suitable only
for soils containing insignificant quantities of silt and clay.
Two methods of determining the size distribution of fine particles down
to the clay size by sedimentation are specified, namely the pipette method and the
hydrometer method, in both of which the density of the soil suspension at various
intervals is measured.
24
Combined sieving and sedimentation procedures enable a continuous
particle size distribution curve of a soil to be plotted from the size of the coarsest
particles down to the clay size.
Some type of grain-size analysis is universally used in the engineering
classification of soils. Part of the suitability criteria of soils for road, airfield,
levee, dam and other embankment construction is the grain-size analysis.
Information obtained from the grain-size analysis can be used to predict
soil-water movement, although the permeability tests are more generally used.
3.3.5.1 Dry Sieving Method
The grain-size analysis is an attempt to determine the relative proportions
of the different grain sizes that make up a given soil mass. Obviously, to have
significance the sample must be statistically representative of the soil mass.
Actually it is not possible to determine the individual soil sizes. The test can only
bracket the various ranges of sizes. This is accomplished by obtaining the
quantity of material passing through a given sieve opening but retained on a sieve
of smaller sized openings and then relating this retained quantity to the total
sample. It is evident that the material retained on any sieve in this manner
consists of particles of many sizes, all of which are smaller than the openings of
the sieve through which the material passed but larger than the openings of the
sieve on which the soil is retained.
The sieving process does not provide information on the shape of the soil
grains, that is, whether they are angular or rounded. It only yields information on
grains that can pass, or with proper orientation do pass, through rectangular sieve
opening of a certain size.
25
Information obtained from the grain-size analysis is presented in the form
of a curve. Standard procedure uses the percent passing (also termed percent
finer) as the ordinate plotted to a natural scale of the grain-size distribution curve.
It should be evident that a grained-size distribution curve can only be
approximate. This is for the several reasons considered here, including physical
limitations on obtaining a statistically representative sample, the presence of soil
lumps, the practical limitations of using sieve mesh openings for irregular-shaped
soil particles, and the limit on the number of sieves used in a “stack” for the
analysis.
Sieve washing is not desirable or practical for soils (gravel and gravelly
sands) when less than 10 to 15 percent passes the 2.00mm sieve. Sieve washing
is usually not necessary when only 5 to 10 percent passes the 0.150mm sieve for
the fine-grained soils.
From the grain-size distribution curve, grain sizes such as D10, D60 and
D85 can be obtained. The D refers to the grain size, or apparent diameter, of the
soil particles and the subscript (10, 30, 60) denotes the percent which is smaller.
An indication of the spread (or range) of grain sizes is given by the coefficient of
the uniformity CU, Defined as
Cu 
D 60
D10
3.1
Where,
Cu is the coefficient of the uniformity
D60 is the grain size at 60 percent passing
D10 is the grain size at 10 percent passing
A larger value of CU indicates that the D60 and D10 sizes differ appreciably.
It does not ensure that a condition of gap grading, as when sizes are missing or
present in very small relative quantities, does not exist. The coefficient of
concavity CC is a measure of the shape of the curve between the D60 and D10 grain
sizes, defined as
26
Cc 
D 2 30
D10  D 60
3.2
Where,
Cc is the coefficient of concavity
D30 is the grain size at 30 percent passing
D60 is the grain size at 60 percent passing
D10 is the grain size at 10 percent passing
Values of CC that greatly different from 1.0 indicates grain sizes missing
between the D60 and D10 sizes.
The test method is accordance with BS 1377 : Part 2 : 1900 : Method 9.3
(Dry sieving method)
3.3.5.2 Hydrometer Method
The hydrometer analysis is a widely used method of obtaining an estimate
of the distribution of soil particle sizes from the 0.075mm sieve to around 0.001
mm. The data is plotted on a semi-logarithmic plot of percent finer vs. grain
diameters and be combined with the data from a mechanical analysis of the
material retained on the .075 mm sieve.
The principal value of the hydrometer analysis appears to be obtaining the
percent clay (percent finer than 0.002 mm). Soil behavior for the cohesive soil
fraction depends principally on the type and percent of clay mineral, geologic
history, and water content rather than on the distribution of particle sizes.
The hydrometer analysis utilizes the relationship among the velocity of
fall of spheres in a fluid, the diameter of the sphere, the specific weights of the
sphere and of
27
the fluid, and the viscosity of the of the fluid as expressed by the English physicist
G. G. Stokes(ca 1850) in the equation termed Stokes’ law:
2s  u  D 
v
 
9  2 
2
3.3
Where,
V is the velocity of fall of the spheres, cm/s
s is the specific weight of the sphere
 f is the specific weight of fluid
 is the absolute, or dynamic, viscosity of the fluid, dyne.s/cm2 (or
g/cm.s)
D is the diameter of sphere, cm
g = 980.7 cm/s2
1 g =980.7 dynes
For D and using the specific weight of water, ’w, then:
D
18v
s   ' w
3.4
The range of soil particle diameters D for this equation to be valid is
approximately:
0.0002 mm ≤ D ≤ 0.2 mm
To obtain the velocity of fall of the particles, the hydrometer is used. This
is a device originally developed to read the specific gravity of a solution, but by
altering the scale it can be made to read other values.
The test method is accordance with Engineering Properties Of Soil And
Their Measurement Experiment No. 6 (Hydrometer method).
28
3.3.6
Determination Of Dry Density/ Moisture Content Relationship
This test is for determining characteristics related to the compaction of
soils, which can be used as a basis for specifying requirements for soils
compacted in the field.
Compaction of soil is the process by which the solid particles are packed
more closely together, usually by mechanical means, thereby increasing the dry
density of the soil. The dry density that can be achieved depends on the amount
of water present in the soil. For a given degree of compaction of a given cohesive
soil there is the optimum moisture content at which the dry density obtained
reaches a maximum value. For cohesion-less soils an optimum moisture content
might be difficult to define.
Three types of compaction test can be used, each with procedural
variations related to the nature of the soil. The first is the light manual
compaction test in which a 2.5kg rammer is used. The second is the heavy
manual compaction which is similar but gives a much greater degree of
compaction by using a 4.5 kg rammer with a greater drop on thinner layers of soil.
For both these tests a compaction mould of 1L internal volume is used for soil in
which all particles passing a 20mm test sieve. If there is a limited amount of
particles up to 37.5mm size, equivalent tests are carried out in the larger
California Bearing Ratio (CBR) mould. The third type of test makes use of a
vibrating hammer, and is intended mainly for granular soils passing a 37.5mm
test sieve, with no more than 30 percent retained on a 20mm test sieve. The soil is
compacted into a CBR mould.
Compaction using 4.5kg rammer for soils with particles up to
medium-gravel size will be discussed here. This test covers the determination of
the dry density of soil passing a 20mm test sieve when it is compacted in a
specified manner over a range of moisture contents. The range includes the
optimum moisture content at which the maximum dry density for this degree of
29
compaction is obtained. The mass of the rammer is 4.5 kg, the height of fall to
450 mm, and the numbers of compacted layers are five. 1L compaction mould is
used.
The test method is accordance with BS 1377 : Part 4 : 1900 : Method 3.5
(Method using 4.5 kg rammer for soils with particles up to medium-gravel size).
3.3.7
In-situ Density Test
Sand replacement method using small pouring cylinder is the test method
that suitable for fine- and medium-grained soils. This method covers the
determination in-situ of the density of natural or compacted soils for which a
115mm diameter sand-pouring cylinder is used in conjunction with replacement
sand. The method is applicable to layers not exceeding 150mm in thickness.
The whole research experiment can be divided into 4 stages.
Stage (I): Preparation of the materials and apparatus:
i.
Assemble all the necessary apparatus both for laboratory calibration and
for site use.
ii.
Prepare the standard sand and river sand as stated in BS1377 Part 9:1990
clause 2.1.3, that is, carry out the grading test or sieving analysis of the
sand such that 100% passes a low m test sieve and 100% is retained on the
0.0063mm test sieve.
Stage (II): Calibration of the standard sand and river sand at laboratory:
30
i.
The prepare sand shall be oven dried and stored in a loosely covered
container about 7 days to allowed its moisture content to reach
equilibrium with atmosphere humidity.
ii.
Determination of the mass of sand in the cone of the pouring cylinder at
the laboratory. Fill the sand pouring cylinder with clean sand so that the
level of
the sand in the cylinder is within about 10 mm from the top. Find out the
initial weight of the cylinder plus sand (m1). And this weight should be
maintained constant throughout the test for which the calibration is used.
iii.
Allow the sand of volume equal to that of the calibrating container to run
out of the cylinder by opening the shutter, close the shutter and place the
cylinder on the glass sand takes place in the cylinder close the shutter and
remove the cylinder carefully. Weigh the sand collected on the glass plate.
Its weight (m2) gives the weight of sand filling the cone portion of the
sand pouring cylinder. Repeat this step at least three times and take the
mean weight (m2). Put the sand back into the sand pouring cylinder to
have same initial constant weight (m1).
iv.
Determination of the bulk density of the sand (ρa) that is determine the
internal volume. V(in mL) of the calibrating container.
v.
Calculate the bulk density of the sand, ρa (in Mg/m3), from the equation,
a 
ma
V
   equa3.1
ma  m1  m3  m 2
a 
ma
V
3.5
3.6
Where,
ma is the mass of sand required to fill the calibrating container (in
g).
m1 is the mass of cylinder and sand before pouring into calibrating
container(in g).
m2 is the mean mass of sand in cone (in g).
31
m3 is the mean mass of cylinder and sand after pouring into
calibrating container (in g).
V is the volume of the calibrating container (in mL).
Stage (III): Conduct the in-situ field density at the chosen location.
i.
Chose the location at site to carry out the in-situ field density test.
Approximately 60 square cm of area of soil to be tested should be
trimmed down to a level surface, approximately of the size of the
container. Keep the metal tray on the level surface and excavate a circular
hole of volume equal to that of the calibrating container. Collect all the
excavated soil in the tray and find out the weight of the excavated soil
(Ww). Remove the tray, and place the sand pouring cylinder filled to
constant weight so that the base of the cylinder covers the hole
concentrically. Open the shutter and permit the sand to run into the hole.
Close the shutter when no further movement of the sand is seen. Remove
the cylinder and determine its weight (m3).
ii.
Carry out 2 series of test for standard sand and 3 series of test using
prepared river sand at nearby location.
iii.
Collect data.
iv.
Determine moisture content at laboratory.
Stage (IV): Analyze the collected data.
i.
Calculate the bulk and dry in situ field density test.
ii.
Interpretation of the result.
iii.
Establish the co-efficient factor between stand sand and river sand.
32
3.4
Data Analysis Method
From the calibration at laboratory for the prepare sand, a is obtained. From
the in-situ field density test the Mb, that is the mass of sand required to fill the
excavated hole is obtained. To calculate the bulk density of the soil, ρ(in Mg/m3),
from the equation:

Mwa
Mb
3.7
Where,
Mw is the mass of soil excavated (in g).
Mb is the mass of sand required to fill the hole (in g).
Then, calculate, the dry density,
d 
100 b
100  w
3.8
Where,
ρb is the bulk density
w is the moisture content of the soil.
Compare the ρd of the standard sand(silica) or river sand for the
consistency and co-relationship, that is:
K
Where,
dSilica
dRiver
3.9
33
K is the correlation factor
ρdriveris the dry density of river sand
ρdsilica is the dry density for silica sand
Photo 3.1: River Sand From Batang Sadong , Samarahan Division
34
Photo 3.2: Standard (silica) Sand
Photo 3.3: River Sand and Silica Sand used For In Situ Field Density Test
35
Photo 3.4A: Laboratory Sand Calibration
Photo 3.4B: Laboratory Sand Calibration
36
Photo 3.4C: Laboratory Sand Calibration
Photo 3.5A: In situ Testing In Progress
37
Photo 3.5B: In Situ Testing In Progress
Photo 3.6A: Field Density Test Set 2
38
Photo 3.6B: Field Density Test Set 5
Photo 3.6C: Field Density Test Set 6
39
Photo 3.6D: Field Density Test Set 8
Photo 3.6E: Field Density Test Set 9
40
Photo 3.6F: Field Density Test Set 10
Photo 3.6G: Field Density Test Set 11
41
Photo 3.7A: Moisture Content Test (Oven Dried Method)
Photo 3.7B: Moisture Content Test
42
Photo 3.8: Particle Density Test
Photo 3.9: Sieving Analysis
43
Photo 3.10A: Liquid Limit and Plastic Limit Test
Photo 3.10B: Liquid Limit Test (Cone Penetration Test)
44
Photo 3.11: Laboratory Compaction Test