Construction Material Testing Lab Manual Part I.doc

Preface
This manual describes the procedures for laboratory testing of road construction and
building materials carried out at Central Materials Laboratory and at construction site
Laboratory. The test procedures are in essence based on AASHTO, ASTM and British
Standard methods of Sampling and Testing.
To enhance the understanding of the testing principles and procedures, illustrative
examples, standard test data sheets, diagrams, figures, and test result reports are
included. The user is supposed to strictly follow the routine testing procedures described
in the relevant sections of the manual. Besides, it is essential to use this manual in
conjunction with the reference standards; i.e. AASHTO, ASTM and BS Standards.
Manual part I presents details of the methods for Atterberg limits, Particle size analysis,
AASHTO and unified soil classification, Moisture – Density Relationship (compaction),
the California Bearing Ratio (CBR) , Specific Gravity and In-place Density of soil-
aggregates.
This testing manual has been prepared and compiled by SABA Engineering Plc, as part
of the assignment for Consultancy Services for The Establishment of Regional
Construction Materials Testing Laboratories for 11 towns in Ethiopia. Preparation of this
soils and materials manual has been a component under the Contract Agreement signed
between the MoWUD, the implementing body on behalf of the Ministry of Capacity
Building, Public Sector Capacity Building (PSCAP) Support Project and SABA
Engineering Plc. The project is financed by the World Bank.

TABLE OF CONTENT
Page
Introduction --------------------------------------------------------------------------------------------1
Moisture Content --------------------------------------------------------------------------------------13
Atterberg Limits
Casagrande - Liquid Limit Method ----------------------------------------------------------------15
Plastic Limit -------------------------------------------------------------------------- 25
Plasticity Index ---------------------------------------------------------------------- 28
Cone Penetrometer Liquid Limit ------------------------------------------------------------------28
Soil Classification
AASHTO Soil Classification ----------------------------------------------------------------35
Unified Soil Classification ------------------------------------------------------------------44
Shrinkage Limits
Volume Metric -------------------------------------------------------------------------------- 48
Linear ------------------------------------------------------------------------------------------ 54
Amount of Material Finer than No. 200 sieve ---------------------------------------------------- 59
Standard Method of Mechanical Analysis of Soil ------------------------------------------------ 62
Hydrometer Analysis --------------------------------------------------------------------------------- 65
Specific Gravity of Soil ------------------------------------------------------------------------------- 84
Moisture Density Relationship --------------------------------------------------------------------- 91
California Bearing Ratio (CBR) -------------------------------------------------------------------- 107
In-place Density ------------------------------------------------------------------------------------- 129

1
INTRODUCTION
SOIL
1. Soil is derived from the Latin word solium. The upper layer of the earth that may be dug or
plowed specifically, the loose surface material of the earth in which plants grow. The soil is
used in the field of agronomy where the main concern is in the use of soil for raising crops.
The term soil is used for the upper layer of mantle which can support plant. The material
which is called soil by the agronomist or the geologist is known as top soil in geotechnical
engineering or soil engineering. The top soil contains a large quantity of organic matter and
is not suitable as a construction material or a foundation for structures. The top soil is
removed from the earth's surface before the construction of structures.
In soil engineering is defined as an unconsolidated material, composed of solid particles,
produced by the disintegration of rocks. The void space between the particles may contain
air, water or both. The solid particles may contain organic matter. The soil particles can be
separated by such mechanical means as agitation in water.
A natural aggregate of mineral particles bonded by strong and permanent cohesive forces is
called rock.
Soil is composed of loosely bound mineral grains of various size and shapes, organic
material, water and gases.
The bonds holding solid particles together in most soil are relatively weak in comparison to
most sound rocks. In fact and air-dried sample of soil will crumble and break down within a
relatively short period when placed in water and gently agitated.
The solid particles of which soils are composed are usually the products of both physical
and chemical action on weathering. Deposits of these weathered solid constituent may be
found near or directly above the bed rock (residual soils) or organic deposits from which they
were formed. Many soil deposits, however, have been transported from their point of origin
to new locations by such agents as water, wind, ice or volcanic action water-transported
soils are classed as alluvial (deposited by moving water on flood plains, deltos, and bars.

2
The Origin of Soil
Soils are formed by weathering of rocks due to mechanical disintegration or chemical
decomposition. when surface of a rock is exposed to atmosphere for an appreciable
time, it disintegrates or decomposes into small particles and thus the soils are formed.
Soil may be considered as an incidental material obtained from the geologic cycle
which goes on continuously in nature. The geologic cycle consist of erosion,
transportation, deposition and upheaval of soil. Exposed rocks are eroded and
degraded by various physical and chemical processes. The products of erosion are
picked p by agencies of transportation, such as water and wind and are carried to new
locations where they are deposited.
Based on the mode of origin, rocks can be divided into three basic types: igneous,
sedimentary, and metamorphic.
Igneous Rock:- are formed by solidification of molten magma ejected from the deeper
part of the earth's mantle. Molten magma on the surface of the earth cools after being
ejected by either fissure or volcanic eruption.
Sedimentary Rock:- the deposits of gravel, sand, silt and clay formed by weathering
may be come compacted by overburden pressure.
Metamorphic Rock:- is the process of changing the composition and texture of rock
(without melting) by heat and pressure.
Marble:- is formed calcite and dolomite by re-crystallization. The mineral grains in
marble are larger than those in the original rock. Quartzite a metamorphic rock formed
from quartz-rich sand stones.
Soil Structure
Soil particles may vary over a wide range. Soils are generally called gravel, sand, silt, or
clay, depending on the predominant silt of soil particles. To describe soils by their
particle size, several organizations have developed soil-separate-size limits. For the
coarse grained soils, primary structure can frequently be observed with the unaided

3
eye or a hand lens. Methods for observing the structure of fine grained soil (silts and
clays) have been slower in developing.
Water, Solids, and Air Relationships
In the case of primary structures, however, visual observations usually are insufficient,
and indirect means are employed to evaluate this factor roughly. To do this it has been
found convenient to think of any soil as being composed of three states of matter solid,
water and gas or air. Although it is impossible to make this separation into three
separate states in the laboratory, it is convenient to represent soil as shown in figure 1.
Va O
Vv
V Vw Ww W
Vs Ws
Fig. 1
2. Soil Type
A geotechnical engineer should be well versed with the nomenclature and terminology of
different types of soils. The following list gives the names and salient characteristics of
different types of soils, arranged in alphabetical order.
Black cotton Soil
Brown clay
Red clay
Gray clay
Pinkish clay
Bentonite clay
Boulders
Tuff
Desert soils
Cobbles
Gravel
Lateritic
Peat
Sand
Silt
Top soil
Expansive clays
Organic clay
Blue clay
Yellow clay
Green clay
White clay
etc.
Air
Water
Solids

2
1. Desert Soil :- Loose fine deposit sand and silt and dust particles size of the particles is
uniform in gradation.
2. Lateritic Soils :- formed by decomposition of rock, removal of base and silica, and
accumulation of iron oxide and aluminum oxide. The presence of iron oxide gives these
soils the characteristic red or pink color. These are residual soils formed from basalt.
3. Black Cotton soil :- is clay of high plasticity. Its contain essentially the clay mineral
montmorillonite. The soil has high shrinkage and swelling characteristics. The shrinkage
strength of the soil is extremely low. The soil is highly compressible and has very low
bearing capacity. It is extremely difficult to work with such soil.
4. Betonite:- it is a type of clay with a very high percentage of clay mineral montmorillnite.
It is highly plastic clay, resulting from the decomposition of volcanic ash. It is highly
plastic clay, resulting from the decomposition of volcanic ash. It is highly water
absorbent and has highly shrinkage and swelling characteristics.
5. Expansive Clay:- a large volume changes as the water content is changed. This soil
contain the montmorillonite.
6. Clay:- it consists of microscopic and sub-microscopic particles derived from the chemical
decomposition of rock. It contains a large quantity of clay minerals. It can be made
plastic by adjusting the water content. It exhibits considerable strength when dry. Clay
is a fine grained soil. It is a cohesive soil the particle size is less than 0.002mm.
7. Gravel:- gravel is a type of coarse-grained soil. The particles size ranges from 4.75mm to
75mm.
8. Cobbles:- cobbles are large size particles in the range of 75mm to 300mm.
9. Boulders:- boulders are rock fragments of large size, more than 300mm in size.
10. Peat:- it is an organic soil having fibrous aggregates of macroscopic and microscopic
particles. It is formed from vegetal matter and different plants, animals wast water under
conditions of excess moisture, such as in swamps. It is highly compressible and not
suitable of foundation.

3
11. Sand:- it is a coarse-grained soil, having 0.075 to 4.75mm size. The particles are visible
to naked eye. The sand is most of product from river.
12. Silt:- it is a fine grained soil, with particle size between 0.002 to 0.075mm the particle
size is not visible to naked eye. It has non or little plasticity and no more swelling and
cohesion less.
13. Tuff:- it is a fine-grained soil composed of very small particles ejected from volcanoes
during its explosion and deposited by wind or water.
14. Top Soil:- top soil are surface souls that support and grow plants, they contain a large
quantity of organic matter and are not suitable for foundation.
3. Soil Mechanics
Soil mechanics is the application of the laws of mechanics and hydraulics to engineering
problems dealing with sediments and other unconsolidated occultation of solid particles
produced by the mechanical and chemical disintegration of rock regardless of whether or
not they contain on admixture of organic constituents; soil mechanics is therefore, a branch
of mechanics which deals with the action of forces on soil and with the flow of water in soil.
4. Geotechnical Engineering Soil
In an applied science dealing with the applications of principles of soil mechanics to
practical problems. It has a much wider scope than soil mechanics, as it deals with all
engineering problems related with soils. It includes soil investigations, design and
construction of foundations, earth-retaining structures and earth structures.
5. Soil Engineering
Foundation:- every civil engineering structure, whether it is a building, a bridge, or a
dam, is founded on or below the surface of the earth. Foundations are required to
transmit the load of the structure to soil safely and efficiently.

4
a) Foundation is termed shallow foundation (light load) when it transmits the load to
upper strata of earth.
(A) Shallow Foundation (Footing)
Load
Column
Natural Ground Level
Soil

7
Purpose of Soil Testing
The chemical and physical properties of materials are determined by carrying out different
tests on samples of soil in a laboratory.
Tests for the assessment of engineering properties, such as moisture content, Atterberg
limits, gradation and hydrometer analysis, density, CBR, in-situ density etc.
The parameters determined from laboratory tests, taken together with descriptive data
relating to the soil, area required by soil engineers for many purposes. The more usual
applications are follows.
a) The findings of a site investigation can be supplemented by farther testing as
construction proceed
b) Criteria for the acceptance of a material used in construction
c) Data acquired from classification tests are applied to the identification of soil
of soil strata.
d) Laboratory tests are needed as part of the control measures which are applied
during construction of earth works on for ensuring that the design criteria are
met.
The advantages of laboratory testing are in a field investigation for different construction
projects, the field operations, which includes of the geology and history of the site
subsurface exploration and in place testing, are of prime importance. The determination of
the ground characteristics by in place testing can take into account large scale effects.
However the measurement of soil properties by mans of laboratory tests offers a number of
advantages, as follows:
1. A test can be run under conditions which are similar to, or which different from those
prevailing in situ, as may appropriate.
2. Test can be carried out on material (soils) which have been broken down and
reconstituted.
3. Control of the test conditions, including boundary conditions can be exercised.
4. Control can be exercised over the choice of material which is too be tested.
5. Laboratory testing generally permits a greater degree of accuracy of measurements
that does field tests.

8
The evaluation of soil properties from reliable test procedures has led to a closen
understanding of the nature and probable behavior of soils as engineering materials. Some
of the resulting advantages in the realm of civil engineering construction have been:
a) Increasing economy in the use of soils as construction materials
b) Reduction of uncertainties in the analysis of foundations and earthworks
c) Exploitation of difficult sites
d) Economies in design due to the use of lower factors of safety
e) Erection of structures, and below-ground construction, which would not have been
feasible without this knowledge.
Scope of Manual
This manual is concerned only with soil testing.
Soil Laboratory Testing
Test:- derived from Latin, testum treating or trying gold, metals and silver alloys.
Examination or trial by which the quality of anything may be determined. The process or
action of examining a substance under known conditions in order to determine its identify
or that of one of its constituents. The physical properties of materials are tested in order to
determine their ability to satisfy particular requirements.
Laboratory:- experiments in natural science.
Sample:- a relatively small quantity of material from which the quality of the mass which it
represents may be inferred.
Specimen:- a part of as representative of the whole sample.
This manual deals with standard laboratory.
- Moisture content
- Atterberg limits (LL, PL, PI, SL, LS)
- Compaction
- Classification
- California Bearing Ratio
- In-place Density
- Sieve analysis and hydrometer

9
Method of test for soil (for civil engineering purposes.)
The procedure (tests) described here are based on Standard Practice Specified in the
AASHTO, ASTM and BS (Standard). The main emphasis of the manual, however, is on the
detailed procedures to be followed in preparing samples for and carrying out different tests
in the laboratory. Appropriate to this test, details of the apparatus required, a procedural
stages, and step by step detailed procedures are included. The typical examples, calculation
and plotting of graphs and presentation of results are described.
Finally:- it is essential material testing technician requires a knowledge of good testing
techniques and an understanding of the correct procedures for the soil sample preparation
and for testing. Terminology and units are used metric (SI).

10
Soil Survey (Investigation) and Sampling
Purpose of the Soil Investigation (survey) is an essential part of a preliminary engineering
soil survey for location and design purposes. Information on the distribution of soil material
and ground-water table and conditions must be obtained before a reasonable and economic
design can detailed soil survey (investigation) provides pertinent information on the following
subject.
1. The selection of the type of surface and its design.
2. The design of the roadway section
3. The location of the road, both vertically and horizontally
4. The design and location of culvert ditches and drains.
5. The need for subgrade treatment and the type of treatment required.
6. The location and selection of borrow material for files and subgrade treatment.
7. The selection of local sources of construction materials for subbase, base course and
surfacing or wearing course.
The soil survey consists of the following:
- The exploration of the site of the road location by test pit or auger borings and the
preparation of soil profiles the significant soil layers. The critical depths to bed rock
and water table and the extent of adverse ground conditions such as swaps or peat
bogs.
- The study of all existing information on soil, and ground-water conditions occurring
in the vicinity of the proposed road location.
- The identification of the various soil types from soil profile characteristics occurring
on the proposed road project.
- The taking of representative samples of soil and local construction materials
(subbase, base course and surfacing materials) for laboratory testing.
Road site Exploration:- the field work for this phase of the soil survey consists of making
examinations of the soils by means of borings, test pits or road cuttings. Borings for
foundation should be deep enough to determine if bed rock, adverse ground (peat) or water
conditions are apt to be encountered during the construction of the proposed road. After the
boundaries of each soil type are established, sampling sites are selected so that
representative samples can be obtained for laboratory test purposes.

11
Equipment for Soil Survey
The type of equipment required for making a soil survey.
1. Ouger
2. Rod
3. Tape
4. Sample bags
5. Shovel
6. Pick
Soil sampling or selection:- sample of soil or gravel should be obtained from each soil layer
(depth) and limited distance with pick and shovel from the proposed test pit selected on the
basis of a study auger boring or test pit records. Each sample should be placed in a canvas
bag, marked with adequate identification, tied securely and shipped to the laboratory. A
sufficient amount and number of samples should be taken to establish the range in test
results for what appears to be the same soil layer.
Or soils survey should be conducted along the proposed route in order to asses the existing
pavement condition including soil extension. Construction materials subbase material
(select material source, base course material, surfacing and water should be sampled for
laboratory test determination.

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SECTION I
1. MOISTURE CONTENT AND INDEX TESTS
1.1 Moisture Content (BS1377: Part 2: 1990 and ASTM D2216)
1. Definition
The mass of water which can be removed from the soil and aggregate by heating (oven
drying) at 105 - 1100c expressed as a percentage of the dry mass.
2. Apparatus
- Moisture can (container)
- Balance
- Oven
- Spatula
- Pan
3. Procedure
Clean and dry the moisture can (container). Make sure that all are marked the same
reference no. or letter.
a. Weigh each container and record.
b. Place the wet sample in the container, the mass of sample to be used as follows:
Mass of soil sample 50-300 gm
Mass of aggregate sample 300-500 gm
c. Weigh wet of sample + container and record
d. Place the wet sample + container in the over. Maintain the required temperature
normally 105-1100c for 12 - 24 hours.
e. Remove the sample from the oven and allow in the air to cool at least 10-15min.
f. Weigh the dried sample + container and record.

14
4. Calculation:-
The moisture content of a soil or aggregate is expressed as a percentage of its dry mass.
Moisture content = A - B
B - C
Where A. Weight of wet sample + Container
B. Weight of dry sample + Container
C. Weight of Container
1.2 Atterberg Limits
1.2.1 Determining the Liquid Limit of Soil (AASHTO Designation T89-90)
1. Definition:
The liquid limit of a soil is the moisture (water) content at which soil passes from the
plastic to liquid state as determined by the liquid limit test.
2. Apparatus:
a. Mixing (Evaporating dish) about 114mm diameter
b. Spatula or peel knife having blade about 76 mm length and 19 mm width
c. Motorized liquid limit device
d. Grooving tool
e. Moisture can (container)
f. Balance sensitive to 0.01gm
g. Pan (small)
h. Drying oven
i. Graduated measuring cylinder 10-50ml
3. Sample preparation
The soil sample as received sufficient from field - A sample shall be taken from the
thoroughly mixed portion of the material passing the No 40(0.425mm) sieve which
has been obtained in accordance with the standard method of preparing disturbed
soil sample or the standard method of wet preparation of disturbed soil sample for
test.
Dry preparation - Allow the sample in air to dry at room temperature or in an oven at
a temperature not exceeding 600c. Break down aggregations of particles in a mortar

15
using a rubber pestle but avoid crushing individual particles. Place in the cup or dish
a sample weighing about more than 100gm.
4. Procedure
4.1 Adjustment of Mechanical Device:-
The liquid limit device shall be inspected to determine that the device is in good
working order, that the pin connecting the cup is not worn sufficiently to permit
side play that the screws connecting the cup to the hanger arm are tight and
that a groove has not been worn in the cup through long usage. The grooving
tool shall be inspected to determine that the critical dimensions are as shown
Fig. 1.1.
By means of the gauge on the handle of the grooving tool and the adjustment
plat H, Fig 1.1, the height to which the cup is lifted shall be adjusted so that the
point on the cup which comes in contact with the base is exactly 1cm (0.3937")
above base.
The adjustment plate H shall than be well secured by tightening the screws 1.
With the gage still in place revolving the crank rapidly several times shall check
the adjustment. If the adjustment is correct, a slight ringing sound will be heard
when the cam strikes the cam follower. If the cup is raised off the gauge or no
sound is heard further adjustment shall be made. The apparatus must be clean
and the bowl must be dry and oil free. Check that the grooving tool is clean and
dry, and conforms to the correct profile.
The machine should be placed on a firm solid part of the bench so that it will
not wobble. The position should also be convenient for turning the handle
steadily and at the correct speed (two turns per second). Practice against a
second's timer with the cup empty to get accustomed to the correct rhythm.
4.2 Mixing:-
The soil sample shall be placed in the evaporating (mixing) dish and add
sufficient distilled water and mix the soil sample in the mixing dish with the
spatula for at least 10min. some soils especially heavy clay may need a longer
mixing time up to 45min. When sufficient water has been thoroughly mixed
with the soil to form a uniform mass of stiff consistency, a sufficient quantity of

16
this mixture shall be placed in the cap above the spot where the cap rests on
the base and shall then be squeezed and spread into the position shown in Fig.
1.2 with as few strokes of the spatula as possible, care being taken to prevent
the entrapping of air bubbles within the mass. With spatula the soil shall be
leveled and at the same time trimmed to a depth of 10mm at the point of
maximum thickness. The excess sample shall be returned to the mixing dish.
The sample in the cup of the mechanical device shall be divided by a firm stroke
of the grooving tool along the diameter through the centerline of the cum
follower so that a clean sharp groove of the proper dimensions will be formed. To
avoid tearing of the sides of the groove or slipping of the soil cake in the cup,
upto six strokes from front to back or from back to front counting as one stroke
shall be permitted. The depth of the groove should be increased with each
stroke and only the last stroke should scrape the bottom of the cup.
4.3 Turn the crank handle of the machine at a steady rate of two revolutions per
second, so that the bowl is lifted and dropped. Use a second's time if necessary
to obtain the correct speed. If a revolution counter is not fitted, count the
number of bumps counting aloud if necessary. Continue turning until the
groove is closed along a distance of 13mm. The back end of the standard
grooving tool serves as a length gauge. The groove is closed when the two parts
of the soil come into contact at the bottom of the groove. Record the number of
blows required to reach this condition. If there is a gap between two

20
Points of contact continue until there is a length of continuous contact of
13mm, and record the number of blows.
4.4 Remove a slice of soil approximately the width of the spatula extending from
edge of the soil. Followed together shall be removed and placed in two suitable
containers. The containers and samples shall be weighed and the weight
recorded.
4.5 The soil remaining in the cup shall be transferred to the evaporating dish. The
cup and grooving tool shall then be washed, clean and dried in preparation for
the next trials.
4.6 The foregoing operation shall be repeated for at least two additional portions of
the samples to which sufficient water has been added to bring the soil to a more
fluid condition. The object of this procedure is to obtain samples of such
consistency that at least one determination will be made in each of the following
ranges of blows; 1st 25-35, 2nd 20-30, 3rd 15-25.
4.7 Place all the weighed and recorded sample and container in the oven to dry [see
Section 1.1 (d-f)].
4.8 Calculation:-
The water content of the soil shall be expressed as the moisture content in
percentage of the weight the oven dried mass and shall be calculated as follows.
% Moisture content = (A-B) x 100
B-C
Where A = weight of wet sample + container
B = weight of dry sample + container
C = weight of container
4.9 Preparation of flow curve
Using a semi-logarithmic chart, plot the moisture content as ordinate (linear
scale) against the corresponding number of blows as abscissa (logarithmic scale)
and the number of blows as ordinates on the logarithmic scale. The flow curve
shall be a straight line drown as. It may be used to determine the liquid limit for
a soil with only one test; this procedure is generally called the "one point

21
method" this method has been adopted by ASTM under the designation D423-
66, Liquid limit = WN (N/25) n
Where N = number of blows in liquid limit device for 0.5in, groove closure
WN = corresponding moisture content
n = 0.121 for all soils.
The reason for obtaining fairly good results by the one point method is due to
the small range of moisture involved for N between 20 and 30.
The following table gives the values of (N)/25)0.121 for N=20 to N=30
N (N/25) 0.121
20 0.973
21 0.979
22 0.985
23 0.990
24 0.995
25 1.000
26 1.005
27 1.009
28 1.014
29 1.018
30 1.022

23
nearly as possible through the three or more plotted points. This is called the
flow curve.
4.10 Liquid Limit Determination:-
Draw the ordinate representing 25 blows and where it intersects the flow carve
draw the horizontal line to the moisture content axis. Read off this value of
moisture content and record it on the horizontal line to the nearest 0.1%.
Fig. 1.2 Liquid limit (Casagrande test) Result and Graph
1.2.2 Determining the Plastic Limit and Plasticity Index of Soil
(AASHTO Designation T 90-90)
Definition:-
The moisture content at which a mixture of soil passes from a liquid state to that of a
semi-solid state.

24
1. Sample Preparation
If the plastic limit analysis required take a quantity of soil weighing about 30-
50gm from the thoroughly mixed portion of the material passing the No 40
(0.425mm) sieve [see section 1.2.1 (3)].
2. Apparatus
1. Glass plate reserved for rolling of threads. This should be smooth and free
from scratches, soil and grease and about 300mm square and 10mm thick.
2. Palette knife or spatula
3. A short length 100mm length 3mm diameter of metal rod
4. Standard moisture content apparatus [section 1.2.1 (2)]
3. Procedure
- Prepare chilled or a small portion of thoroughly or mixed sample from the first
trial of LL test.
- Roll into ball
- Roll into thread until crumbling occurs.
a. Rolling into a Ball
Mould the ball between the fingers and roll between the palms of the hands so
that the warmth of the hands slowly dries it. Squeeze an ellipsoidal shape
mass. Roll this mass between the fingers and the ground glass plate with just
sufficient pressure to roll the mass into a thread of uniform diameter through
out its length. Equalize the distribution of moisture, and then form into a
thread about 6mm diameter, using the first finger and thumb of each hand.
The thread must be intact and homogenous. The pressure should reduce the
diameter of the thread from 6mm to about 1/8in or 3mm after between five
and ten back and front movements of the hand. Some heavy expansive clays
may need more than this because this type of soil tends to become harder
near the plastic limit. It is important to maintain a uniform rolling pressure
throughout: do not reduce pressure as the thread approaches 3mm diameter.
When the diameter of the thread becomes 1/8in (3mm) break the thread into
six or eight pieces. Squeeze the pieces together between the thumbs and
fingers of both hands into a uniform mass roughly ellipsoidal in shape and re-
roll. Continue this alternate rolling to a thread 1/8in. (3mm) in diameter
gathering together kneading and re-rolling, until the thread crumbles and

25
occurs surface cracks, under the pressure required for rolling and the soil can
no longer be rolled into thread. The crumbling may occur when the thread has
a diameter greater than 1/8in. (3mm). This shall be considered a satisfactory
end point provided the soil has been previously rolled into a thread 1/8in.
(3mm) in diameter. The crumbling will manifest itself differently with the
various types of soil. Some soils such as dulotancy tuff, ash etc fall apart in
numerous small aggregations of particles. Others may form an outside tubular
layer that starts splitting at both ends. The splitting progress toward the
middle and finally the thread falls apart in many small ploty particles. This
type of samples should no longer be rolled.

27
a. Gather the pieces together after crumbling stage is reached. Divide into two
parts and place in a suitable moisture can (container), weigh the container
and wet soil, record the weight.
Place the moisture can and wet sample in the over. Maintain the required
temperature normally 105-1100c for 12-24 hours. Remove the sample from
oven and allow in the air for about 5-10min. Weigh the dried sample and
moisture can and record.
b. Calculation
Moisture content (A-B) x 100 (plastic limit)
B-C
Refer section 1.2.1 (4.8)
1.2.3 Plasticity Index
The difference between the liquid limit and plastic limit is calculated to give the
plasticity index (PI).
Eg. Plasticity Index (PI) = Liquid Limit (LL, PL) Plastic Limit (PI).
(If LL=40 and PL=21, then PI=40-21=19)

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1.3 Liquid Limit - With Cone Penetrometer
1.3.1 General
This method is used for determining the liquid limit of soil. It is based on the
measurement of penetration into the soil of a standardized cone of specified mass. At
the liquid limit the cone penetration is 20mm, it requires the same apparatus as is
used for bituminous material testing but fitted with a special cone.
1.3.2 Apparatus
1. A flat glass plate, of convenient size, 10mm thick and about 500mm square.
2. Spatulas or palette knives.
3. Cone for the penetrometer, stainless steel or duralumin with smooth polished
surface, length approximately 35mm, cone angle 300, sharp point mass of cone
and sliding shaft 80g±0.1g.
4. Sharpness gauge for cone, consisting of a small steel plate 1.75mm ±0.1mm thick
with a 1.5mm±0.02mm diameter hole accurately drilled and reamed.
5. Metal cups of brass or aluminum alloy 55mm thick and 40mm deep.
6. Metal straight edge about 100mm long.
7. Moisture content apparatus.
8. An evaporating dish (mixing dish), about 150mm diameter.
9. Wash bottle or beaker, containing distilled water.
1.3.3 Sample preparation
a. Use of Natural Soil:-
When the soil consists of clay and silt with little or no material retained on a
No.40 (0.425mm) sieve, it can be prepared for testing from its natural state.
Take a representative sample of about 500g of soil and chop into small pieces or
shred with cheese grater. Mix with distilled water on a glass plate, using two
palette knives. During this process remove any coarse particles by hand or with
tweezers. Mix the water thoroughly into the soil until a thick homogeneous paste
is formed and the paste has absorbed all the water with no surplus water visible.
The mixing time should be at least 10min. with vigorous working of the palette
knives. A longer mixing time period up to 45min may be needed for some soils,
which do not readily absorb water.

29
Place the mixed soil in an airtight container, such as a sealed polythene bag, and
leave to mature for 24 hours. A shorter maturing time may be acceptable for low
plasticity clays, and very silty soils could be tested immediately after mixing. If in
doubt, comparative trial tests should be performed. In a laboratory with a
continuous workload it is good practice to be consistent and allow 24 hours
maturing for all soils.
The mixed and matured materials is then ready for the tests.
b. Wet preparation :-
Take a representative sample of the soil at its natural moisture content to give at
least 350gm of material passing the No.40 (0.425mm) sieve. This quantity allows
for a liquid limit and a plastic limit test. Chop into small pieces or shred with a
cheese grater, and place in a weighed beaker, weigh and determine the mass of
soil m(g) by difference.
Take a similar representative sample and determine its moisture content w(%).
The dry mass of soil in the test sample mD(g) can then be calculated from the
equation:.
mD = 100m
100+w
Add enough distilled water to the beaker to just submerge the soil. Break down
the soil pieces and stir until the mixture forms slurry. Nest a No. 40 (0.425mm)
sieve on a receiver, under a guard sieve eg. No 10 (2mm) sieve if appropriate. Pour
the slurry through the sieve or sieves, and wash with distilled water, collecting all
the washings in the receiver. Use the minimum amount of water necessary, but
continue washing until the water passing the No. 40 (0.425) sieve runs virtually
clear. Transfer all the washings passing the sieve to a suitable beaker with out
losing any soil particles.
Collect the washed material retained on the sieves. Dry in the oven and determine
the dry mass mR(g).
Allow the soil particles in the beaker to settle for several hour, or overnight. If
there is a layer of clear water above the suspension, this may be carefully poured
or siphoned off, without losing any soil particles. However if the soil contains

30
water-soluble salts which might influence its properties, do not remove any water
accept by evaporation.
Stand the container in a warm place or in a current of warm air, so that it can
partially dry. Protect from dust. Stir the soil water mixture frequently to prevent
local over-drying. Alternatively, excess water may be removed by filtration. When
the mixture forms a stiff paste such that the penetration of the cone penetrometr
would not exceed 15mm the soil is ready for mixing on the glass plate as
described above. No additional curing time is required and the material is ready
for the tests.
Calculate the percentage by dry mass of soil in the original sample passing the
0.425mm sieve (Pa) from the equation
Pa = mD - mR x 100
mD
c. Dry preparation:-
Allow the soil sample to air dry at room temperature, or in one oven a
temperature not exceeding 500c [see section 1.2.1(3)].
1.3.4 Procedure
a. Take a sample of about 300gms-soil paste and place the prepared soil paste on
the glass plate.
b. Mix the soil paste on the glass with the spatulas for at least 10-min. Some soil
especially heavy clays may need a longer mixing time. If necessary add more
distilled water so that the first cone penetration reading is about 15mm.
c. Press the mixed soil paste into the cup with a palette knife (spatula) taking care
not to trap air. Strike off excess soil with the straight edge to give a smooth level
surface.
d. Lock the cone shaft unit near the upper end of its travel and lower the supporting
assembly carefully so that the tip of the cone is within a few mms of the surface of
the soil in the cup. When the cone is in the correct position, a slight movement of
the cup will just make the soil surface. Lower the stem of the dial gauge to
contact the cone shaft and record the reading of the dial gauge to the nearest
0.1mm.

32
e. Release (Allow) the cone by pressing the button for a period of 5±1 second timed
with a seconds timer or watch. If the apparatus is not fitted with an automatic
release and locking device, take care not to jerk the apparatus during this
operation. After 5 seconds release the button so as to lock the cone in place.
Lower the dial gauge stem to make contact with the top of the core shaft without
allowing the pointer sleeve to rotate relative to the stem adjustment knob. Record
the reading of the dial gauge to the nearest 0.1mm Record the difference between
the beginning and end of the drop as the cone penetration. See Fig. 1.3.
f. Lift out the cone and clean it carefully to avoid scratching.
g. Add a little distilled water and remix and add a little more wet soil to the cup,
taking care not to trap air, make the surface smooth. Repeat section 1.3.3(d). If
the second cone penetration differs from the first by less than 0.5mm, the average
value is recorded, and proceed to the next h.
h. If the second penetration is between 0.5 and 1mm different from the first, a third
test is carried out provided that the overall range does not exceed 1mm, the
average of the three penetrations is recorded and the content is measured stage
(1).
i. If the overall range exceeds 1mm, the soil is removed from the cup and re-mixed
and the test is repeated from stage C.
j. Take a moisture content sample of about not less than 10g, the area penetrated
by the cone, using the tip of a small spatula. Place it in a suitable container and
determine its moisture content.
k. The soil remaining in the cup is re-mixed with the rest of the sample on the glass
plate together with a little more distilled water, until a uniform softer consistency
is obtained. The cup is scraped out with the square-ended spatula wiped clean
and dried, and stages (C-J) are repeated at least three more times, with further
increments of distilled water.

34
A range of penetration values from about 15mm to 25mm should be covered,
fairly uniformly distributed.
1. Calculation
The moisture content of the soil from each penetration reading is calculated
from the wet and dry weightings as in the moisture content [see section 1.2.1
(4.8)].
Moisture content (%) = (A-B) x 100
B-C
Where A = weight of wet sample + container
B = weight of dry sample + container
C = weight of container
Test Results
From the graph the moisture content corresponding to a standard cone penetration
of 20mm is read off to the nearest 0% reported to the nearest whole number as the
liquid limit. See Fig. 1.3
1.4 Choice I General Soil classification
1.4.1 General:-
The American Association of State Highway and Transportation Official (AASHTO)
system of soil classification is based upon the observed field performance of soil
under highway pavements and is widely known and used among highway engineers.
1.4.2 Definition:-
Soil classification is systematically grouping or categorizing of soil. It provides a
common language to express briefly the general characteristics of soils.
1.4.3 Procedure:-
The AASHTO soil classification system is classified into seven (7) major groups A-1
through A-7. Soils classified under groups A-1, A-3 and A-2 are granular (gravels,
sand and gravelly clay). Materials with 35% or less passing through a No.200
(0.075mm) sieve. The silt and silty clay materials with more than 35% passing the
No.200 (0.075mm) sieve are classified under groups A-4, A-5, A-6 and A-7. After the
necessary laboratory tests have been preformed the proper classification for a given
material can normally be made without great difficulty. The classification of a specific

35
soil is based upon the results of tests made in accordance with standard methods of
soil testing. To classify a soil by Table 1.1 one must proceed form left to right with the
required test data available by the process elimination. The first group from the left
into which the test data will fit gives the correct classification. To evaluate the
performance quality of a soil as a highway subgrade material under this system, a
number called the group index is included with the groups and sub-groups of the
soil. The group index of a soil may range from 0-20 and is expressed as a whole
number. The approximate subgrade and base performance quality of a given soil is
inversely proportional to its group index, and it can be expressed by the following
empirical relation.
Group index (GI) = (F-35%) [0.2+0.005 (LL-40)]+0.01(F-15)(PI-10)
Where GI = group index
F = percentage of soil passing a No 200 (0.075mm) sieve
LL = liquid limit
PI = plasticity index
The group index is rounded off to the nearest whole number. The group index may
also be evaluated with Fig. 1.4 by adding the vertical reading, the vertical reading is
obtained from the two charts:
 Chart one LL with No. 200 (0.075mm)passing sieve and
 Chart two PI with a No. 200 (0.075mm) passing sieve.
Add the two values.
1.4.4 Classification
Parameters
1. Liquid Limit
2. Plasticity Index
3. Grain Size Analysis
Note:- Detail Soil Classification
General
A-1, A-3, A-2, A-4, A-5, A6 and A-7
1. Granular Materials and Sand: 35% or less passing a No.200
(0.075mm) sieve are A-1, A-3 and A-2.

36
Soil Group A-1 material
divided into two subgroups
Sieve
size
%
passing
LL PI
A-1
A-1-a
No. 10
No. 40
No. 200
50max
30max
15max
- 6 max
A-1-b
No. 40
No. 200
50max
25max
- 6 max
2. Soil Group A-3 Material
Sieve Size % Passing LL PI
A-3
No. 40 51 min
NP NP
No. 200 10 max
Soil Group A-2
material divided into
four subgroups
Sieve
size
%
passing
LL PI
A-2
A-2-4 No.200 35 or less 40 max 10max
A-2-5 No.200 35 or less 41 min 10max
A-2-6 No.200 35 or less 40 max 11 min
A-2-7 No.200 35 or less 41 min 11 min
2. Silt and Silty Clay or Heavy Clay Materials: 35% or more passing No.
200 (0.075mm) sieve are A-4, A-5, A-6, and A-7.
Sieve
Size
%
Passing
LL PI
A-4 No.200 36 min 40 max 10 min
Sieve
Size
%
Passing
LL PI
Soil Group A-5 No.200 36 min 41 max 10 min

37
Sieve
Size
%
Passing
LL PI
A-6 No.200 36 min 40 max 11 min
Sieve
Size
%
Passing
LL PI
A-7 A-7-5 No.200 36 min 41 min 11 min
A-7-6 No.200 36 min 41 min 11 min
Group of soil A-7-5 is plasticity Index result less or equal Liquid Limit – 30 (PI less or
equal to LL-30)
Group of soil A-7-6 is plasticity Index result greater than Liquid Limit result -30 (PI less
than LL-30)

39
Example:- 1
Liquid Limit = 42
Plasticity Index = 12
Passing No 200 (0.075mm) sieve = 35
Soil classification is A-2-7 (1).
Example:- 2
Liquid Limit = 60
Passing No 200 (0.075mm) sieve = 36
Example:- 3
Liquid Limit = 49
Passing sieve No 200 (0.075mm) = 38
Example:- 4
Liquid Limit or Plasticity Index is NP.
Passing sieve No 200 (0.075mm) = 36
Soil classification is A-4 (0).
1.4.5 Soil Fractions
1. Over size (Boulders) - Material retained on 3 inch (75mm) sieve. They should be
excluded from the portion of a sample to which the classification is applied but
the percentage of such material should be recorded.
2. Gravel - Material passing sieve with 3inch (75mm) and retained on the No 10
(2mm) sieve.
3. Coarse Sand - Material passing the No. 10 (2mm) sieve and retained on No. 40
(0.425mm) sieve.
4. Fine Sand - Material passing the No. 40 (0.425mm) sieve and retained on the No
200 (0.075mm) sieve.

40
5. Silty Clay - Material passing the No. 200 (0.075mm) sieve. The word silt is applied
to a fine material having a PI of 10 or less and the term clay is applied to fine
material having a PI of more than 10.
1.4.6 Description of Classification Groups
A. Granular Materials
- Group A-1 - Well graded mixtures of stone fragments or gravel ranging from
course to fine with non-plastic or slightly plastic silt binder.
- Subgroup A-1-a - Stone fragments and sandy gravel some times with silt.
- Subgroup A-1-b - Stone fragments and gravel with some times clayey silt.
- Group A-3 - fine sands and non-plastic silt.
- Group A-2 - sandy gravel with silt and gravelly clay.
- Subgroup A-2-4- and A-2-5- include various granular materials and sandy
clayey silt.
- Subgroup A-2-6 and A-2-7 include materials similar to those described
under subgroups A-2-4 and A-2-5 except that the fine portion contains
plastic clay having a higher PI.

41
3. choice II-Soil Classification
Definition:- soil classification is systematically grouping or categorizing of soil. It provides a
common language to express briefly the general characteristics of soils
A. AASHTO Soil Classification System: is classified into 7 major groups A-1 through A-7
classified and under groups A-1, A-3, A-2, A-4, A-5, A-6, A-7 soils. Under groups A-1, A-
2 and A-3 are granular or gravelly clay and sand materials with 35% or less passing
through a No. 200 (075mm) sieve.
The silt and clay materials with more than 35% passing the No 200 (075mm) sieve are
classified under groups A-4, A-5, A-6 and A-7.
AASHTO Classification Parameters
1. Liquid Limit
2. Plasticity index
3. Grain size analysis
Group A-1 A-2 and A-7 material divided into 4 and 2 sub groups.
A-1
A-1-a
A-1-b
A-2 materials are divided into 4 sub groups.
A-2
A-2-4
A-2-5
A-2-6
A-2-7
 A-1 material can be used for surfacing, base course and subbase.
 A-2 material for subbase and subgrade.
 A-4,5,6 and 7 subgrade only.
A-7 material is divided into two sub groups
A-7
A-7-5
A-7-6

42
A-7-5 Group of Soil Material:- PI is equal to or less than LL-30
A-7-6Group of Material:- PI is greater than LL-30
Examples
LL PI
Passing Sieve (mm)
Soil Classification
2 0.425 0.075
1 42 12 - - 36 A-7-5 (1)
2 70 30 - - 39 A-7-5 (5)
3 30 10 - - 10 A-2-4 (0)
4 41 20 - - 45 A-7-6 (5)
5 NP 20 15 3 A-1-a (1)
A-1 Material:- Stone fragments, gravelly and coarse sand with binder of low plasticity
or NP.
A-2 Materials:- gravelly silt, clay and sand with low and little high plastic material
A-3 Material:- Sand
A-4,5,6 & 7 Materials:- Silty clay and Same fines with few gravel
B. Silty Clay Soil Materials
- Group A-4 - The typical material of this group is fine sandy and silty clay sometimes
non-plastic material, liquid limit not exceeding 40 and PI not exceeding 10.
- Group A-5 - The typical material of this group is similar to that described under
group A-4, except that it is usually of diatomaceous or micaceous character and may
be highly elastic as indicated by the high liquid limit.
- Group A-6 - This typical material is a plastic clay soil. The group includes also
mixture of fine clayey soil and the Plasticity Index may be high.
- Group A-7 - The typical materials and problems of this group are similar to those
described under group A-6 except that they have the liquid limit and the range of
group index values is 1 to 20 with increasing values indicating the combined effect of
increasing liquid limits and plasticity indexes and decreasing percentages of coarse
material.
- Subgroup of A-7-5 - includes those materials with moderate plasticity index in
relation to liquid limit and which may be highly elastic as well as subject to
considerable volume change.

43
- Subgroup of A-7-6 - includes those materials with high plasticity indexes in relation
to liquid limit and which are subject to extremely high volume change.
 Highly organic soils such as peat and muck are not included in this classification.
1.5 Unified Soil Classification System
General
Unified classification system is widely used. This system is an out growth of the Airfield
classification developed by casagrande and is utilized by the corps of engineers. In this
system, soils fall within one of three major categories: curse grained, fine grained and
highly organic soils. These categories are further subdivided into 15 basic soil groups.
The following group symbols are used in the unified system.
G - gravel O - organic
S - sand W - well graded
M - silt P - poorly graded
C - clay U - uniformly graded
Pt - peat L - low liquid limit
H - high liquid limit
Combinations of above letters are used to identify the soils. For expamle, SP is a sand
that is poorly graded and CL and CH indicate clays with low and high liquid limits
respectively.
The essentials of unified classification system are given in Table 1.5.1 and
characteristics pertinent of roads and air fields are sown in Table 1.5.2.
A. Soil components in the unified classification system are as follows:
- Cobbles - above 75mm (3 inch)
- Gravel - 75mm to 4.75mm (3inch - No.4) sieve
- Coarse sand - 4.75mm to 2mm (No 4 - No. 10) sieve
- Medium sand -2mm to 0.425 mm (No 10 to No 40) sieve
- Fine sand - 0.425 mm to 0.075mm (No 40 to No 200) sieve
- Fine silt and clay - passing 0.075mm (0.075) sieve.

44
B. Laboratory test specified for silts and clays are the determination of the liquid limit
and the plastic limit and plasticity index.
C. Laboratory test for coarse-grained soils is based on the grain size analysis. Coarse-
grained materials are those containing 50% or less passing 0.075 mm (No.200) sieve.
Fine grained are those with more than 50% passing 0.075mm (No.200) sieve.
After determining its grain size distribution, liquid limit and plasticity index, the soil
can be classified using table 1.2 and Fig 1.4.
The minus 0.075mm (No. 200) sieve material is "silt" if non-plastic and the liquid
limit and plasticity index plot below the "A" line on the plasticity chart (Fig. 1.4) and
"clay" if plastic and the liquid limit and plasticity index plot above the "A" line. This
holds true for inorganic silts and clays and organic silts, but not for organic clays
since they plot below the "A" line. The "A" line is an arbitrarily drawn line on the
plasticity chart of Fig. 1.4.
The letters in parentheses stand for symbols by which each group is known.
A. Coarse Grained Symbols
GW-GM, GP-GM,_GW-GC, GP-GC, SW-SM, SW-SC, SP-SM
B. Fine Grained Soil Classification with Symbols
ML, MI, MH, MV, ME, CL, CI, CH, CV, CE
In Ethiopian practice this chart is divided into five zones, giving the following
categories for clays and silts.
1. Clays of low plasticity (CL) less than 35, liquid limit or silts of low plasticity (ML)
less than 35 liquid limit.
2. Clays or silts of medium plasticity (CI) or (MI), liquid limit from 35 to 50.
3. Clays or silts of high plasticity (CH) or (MH), liquid limit from 50 to 70
4. Clays or silts of very high plasticity (CV) or (MV), liquid limit from 70 to 90
5. Clays or silts or extremely high plasticity (CE) or (ME), liquid limit exceeding 90.

45
Example
Liquid Limit = 72
Passing No. 200 sieve = 98
Classification is according to the chart (Fig. 1.5.2) = MV. The soil is MV group.

48
1.6 Determining the Shrinkage Factors and Limit of Soils
1. Scope
This procedure furnishes data from which the following soil characteristics may by
calculated:
(a) Shrinkage Limit
(b) Shrinkage Ratio
(c) Volumetric change
(d) Linear shrinkage
A. Determination of Volumetric Shrinkage
2. Apparatus
2.1 Evaporating (mixing) dish about 150mm diameter.
2.2 Spatula or peel knife having a blade above 76mm long and 20mm wide.
2.3 Glass cup about 57mm diameter and 38mm deep with rim ground flat.
2.4 Prong plate, glass or clear acrylic, fitted with three non-corrodible prongs.
2.5 Glass plate, large enough to cover the shrinkage dish.
2.6 Measuring cylinder 25 to 100ml.
2.7 Mercury, rather more than that will fill the glass cup.
2.8 Straight edge, spatula, small tools.

49
2.9 Balance 3000g capacity reading to 0.01g.
2.10 Moisture content can (container).
2.11 Large tray containing a small amount of water to retain any spilled mercury.
2.12 Vaseline
3. Sample preparation
Receive sufficient sample from field prepare. About 50g of soil sample passing the
0.425 (No. 40) sieve from natural soil and place the prepared sample in the mixing
dish or cup.

51
4. Procedure
4.1 Place the prepared soil sample in an evaporating dish and thoroughly mix with
distilled water to make into a readily workable plate. Air bubbles must not be
included. The moisture content should be somewhat greater than the liquid
limit. The consistency should be such as to require about 10 blows of the
Casagrande liquid limit apparatus to close the groove or to give about 25-28mm
penetration of the cone penetrometer.
Add the mixed soil paste to the shrinkage dish so as to fill it about one-third.
Avoid trapping of air. Tap the dish on the smooth surface bench surface to
cause the soil to flow to the edges of the dish. This should also release any small
air bubbles present. The bench should be padded with a few layers of blotting
paper or similar material.
Add a second amount of soil, about the same as the first and repeat the tapping
operation until all entrapped air has been released. Add more soil and continue
tapping, so that the dish is completely filled with excess standing out. Strike off
the excess with a straight edge and clean off adhering soil from the outside.
Immediately after the above, weigh the sample (soil) and dish to 0.01g. Record
as m1.
4.2 Drying
Allow the sample in the dish to dry in the air for at least 12 hours or 24 hours
until its color changes from dark to light. Place it in oven at 600c for 6 hours
and continue at 105 - 1100c and dry to constant mass.
If the shrinkage curve during drying is required, make a series of volume
measurement at suitable intervals before drying in the oven. Leave the soil in
the shrinkage dish exposed to warm air, and when it has shrunk away from the
dish and can be safely handled, determine its volume and mass. Place the soil-
pat on a flat surface to dry further and repeat the measurements until the color
changes from dark to light. Then dry in the oven.

52
4.3 Weighing Dry Mass
Cool in a dessicatoor or in air and weigh the dry soil and dish or container to
0.01g. Record ad md.
4.4 Measurement of Volume
Remove the dried soil-pat carefully from the shrinkage dish. It should be intact
and be kept long enough to dry in air before transferring to the oven.
Place the glass cup in a clean evaporating dish standing on the large tray. Fill
the cup to overflowing with mercury, and remove the excess by pressing the
glass prong plate firmly on top of the cup. Avoid trapping air under the glass
plate. Carefully remove the prong plate, and brush off any mercury drops
adhering to the glass cup. Place the cup into another lean evaporating dish
without spilling any mercury. Place the soil-pat on the surface of the mercury
press the three prongs of the prong plate carefully on the sample so as to force
it under the mercury Fig… Avoid trapping any air; press the plate firmly on to
the dish. Displaced mercury will be filled in the evaporating dish. Brush off any
droplets of mercury adhering to the cup into the dish. Transfer all the displaced
mercury to the measuring cylinder and record its volume (Vd). This is equal to
the volume of the dry soil-pat.
4.5 Measure the dish volume and weight. Clean and dry the shrinkage dish and
weigh it to 0.01g (m2). Its internal volume is determined by measuring the
volume of mercury held. Place the dish in on evaporating dish and fill it to
overflowing with mercury. The evaporating dish will catch the overflow. Place
the small glass plate firmly over the top of the shrinkage dish so that excess
mercury is displaced, but avoid trapping any air. Remove the glass plat carefully
and transfer the mercury to the 25ml-measuring cylinder. Record the volume of
mercury in ml, which is the volume of the shrinkage dish (V1).

53
4.6 Calculations
Calculate the moisture content of the initial wet soil-pat, w1 from the equation.
Moisture content (w1) = (M1-Md) x 100
Md
Dish No. A B C
Wt of dish + wet soil (m1)
Wt of dish + dry soil (m2)
Wt of dish (m1)
Wt of water (m1-m2) (m4)
Wt of wet soil (m1-m3) (m6)
Volume of dish (V1)
Volume of dry soil (V2)
Volume Change (V1-V2) (V3)
Shrinkage limit (Ws) can then be calculated from the equation,
Moisture content (Wo) = (m1-m2) x 100
m5(m2-m3)
Where V1 = volume of wet soil (dish)
V2 = volume of dry soil-pat
m5 = mass (wt) of dry soil
The shrinkage ratio, Rs, can be calculated from
Rs = ms
V2

SABA Engineering Plc.
P.O.Box 62668 Addis Ababa, Ethiopia. Tel. 34 10 65/34 16 17/34 30 04 Fax.. 34 12 30/34 16 17
E-mail sava.eng@telecom.net.et
54
SHRINKAGE LIMIT TEST (VOLUMETRIC)
Lab No.
Dish No. A B C
A. Wt. of dish and wet soil 48 47.5 48.2
B. Wt. of dish and dry soil 36 35.8 36
C. Wt. of dish 10 9 10
D. Wt. of water (A-B) 12 11.7 12.2
E. Wt. of dry soil (B-C) 26 25 26
F. Volume of dish 13 10.8 13
G. Volume of displaced mercury 8 6.4 8
H. Volume of change cc (F-G) 5 5 5
I. D – H 7 6.7 7.2
Shrinkage Limit (I/E) x 100 26.9 26.8 27.7
Shrinkage Ration (E/G) 3.25 3.91 3.25

55
b. Linear Shrinkage
Definition:-
This test gives the percentage linear shrinkage of a soil. It can be used for soils of low
plasticity, including silts, as well as for clays.
1. Apparatus
1.1 Non-corrodible metal mould (Brass), 140mm long and 25mm in diameter
1.2 Flat glass plate as for the liquid limit test
1.3 Palette knives
1.4 Petroleum jelly
1.5 Vernier calipers
1.6 Moisture content apparatus
2. Procedure
2.1 Preparation of mould:-
Clean and dry the mould. Apply a thin film of Vaseline or petroleum jelly to the
inner surfaces to prevent soil from sticking.
2.2 Preparation of sample
About 200g of soil sample passing 0.425mm (No.40) sieve is prepared from soil.
This proportion of the original sample passing the 0.425mm (No.40) sieve is
recorded.
Place the soil in the mixing dish and mix thoroughly with distilled water, as the
liquid limit test. Continue mixing until it becomes a smooth homogenous paste
at about the liquid limit. This is not critical, but it may be checked by using the
cone penetrometer, which should give a penetration of about 20mm.

56
2.3 Place the paste in the mould, avoiding the trapping of air as far as possible, so
that the mould is slightly over filled. Tap it gently on the bench to remove any air
pockets. Level (trim) off along the top edge of the mould with a spatula or
straight edge. Wipe off any soil adhering to the rim of the mould.
2.4 Leave the mould and soil exposed to the air but in a draught-free position so
that the soil can dry slowly.
When the soil has shrunk away from the walls of the mould, it can be
transferred to an oven set at 600c. When shrinkage has virtually ceased,
increase the drying temperature to 105 - 1100c to complete the drying.
2.5 Allow the mould and soil to cool in a dessicator, measure the length of the bar of
soil with the caliper, making two or three readings and taking the average (LD).
If the specimen is curved during drying, remove it carefully from the mould and
measure the lengths of the top and bottom surfaces. Take the mean of these two
lengths as the dry length as (LD).

57
If the specimen has fractured in one place, two portions can be fitted together
before measuring the length. If it has cracked badly, and the length is difficult to
measure, repeat the test using a very slower drying rate leaving the sample and
mould longer in air (about more than 24 hours) before transferring to the oven.
2.6 Calculation
Calculate the linear shrinkage (LS) as a percentage of the original length of the
specimen from the equation,
LS = (1-LD) x 100
LO
Where: LO = original length of the mould
LD = length of dry specimen
Linear Shrinkage Limit
Inician Length (Lo) - wet
Final Length (Ld) - dry
SL = Lo - Ld x 100
LD
Results
The Linear Shrinkage of the soil is reported to the nearest whole Number

58
. AMOUNT OF MATERIAL FINER THAN NO.200(0.075mm) SIEVE
IN AGGREGATE
AASHTO DESIGNATION T-11
1. Scope
This method of test covers a procedure for the determination of the quantity of aggregate
finer than a standard No. 200 (0.075mm) sieve by washing.
This procedure may not determine the total amount of material finer than the No. 200
(0.075mm) sieve. Such a determination may be made by combining washing and dry sieving
as required in the sieve analysis of fine and coarse aggregate.
2. Apparatus
1.1 Sieves - No. 16 and No. 200 (0.075) sieves. The sieves shall be of woven wire-cloth
construction, conforming to the requirements of AASHTO Designation M-92.
1.2 Container - a pan or vessel of a size sufficient to contain the sample, when covered
with water, and to permit vigorous agitation without an advertent loss of any art of the
sample or water.
1.3 Balance - A balance with a capacity of 2000gm and sensitive to 0.1gm.
1.4 Scale - A heavy duty scale with a capacity of at least 50 lb and sensitive to 0.1 lb.
1.5 Drying Oven - an oven capable of maintaining a uniform temperature of 230 ± 90F.
2. Test Sample
The test sample shall be selected from material which has been thoroughly mixed and which
contains sufficient moisture to prevent segregation. Representative samples shall weigh,
after drying, not less than the amount indicated in the following table.

59
Maximum Sieve Size Minimum Sample (Mass)Weight
No. 4 500gm
3/8 inch 1000gm
¾ inch 2500gm
1 ½ inch or over 5000gm

60
3. Test Procedures
Dry the test sample to constant weight (± 16 hours) at a temperature of 230±90F, and
weigh the sample to the nearest 0.1 percent.
Place the sample in a suitable container, and cover the sample with water. Agitate the
contents of the container by vigorous stirring with a large spoon or rod, and pour the
wash water over the nested sieves, arranged with the No. 200 sieve on the bottom. The
agitation should be sufficiently vigorous so that all particles finer than the No. 200 sieve
are brought into suspension and are subsequently washed through the nested sieve. Be
careful to avoid loss of the coarser particles. Repeat this washing operation until the
wash water is clear.
If the material consists of clay, it may be advantageous to let is soak 16 to 20 hours and
to add a detergent to assist deflocculation.
In the case of soil samples, it is often advantageous to separate the sample on the No. 4
sieve. The material passing the No.4 sieve may be washed as outlined above. The
material passing the No. 4 sieve may be washed as outlined above or by means of a
suitable mechanical washing device.
Return all material retained on the nested sieves to the washed sample. Dry the sample
to constant weight (± 16 hours) at a temperature of 230±90F, and weight the sample to
the nearest 0.1 percent.
Pan - drying shall be permissible when oven - drying is impracticable or impossible.
However, in no case shall a sample be heated in excess of 2390F.
4. Calculation
The percentage of material finer than the No. 200 sieve shall be calculated as follows:
F = W - W1 x 100
W
Where F = the percent of material finer than the No. 200 sieve.
W = the original dry weight of the sample
W1 = the dry weight of the sample after washing.
5. Precautions
The No. 200 (0.075) sieve is extremely delicate, and should be handled accordingly. In no
event should wire brushes be used on this sieve.
Take care to avoid loss of sample material during washing and during transfer of
material from the nested sieves to the washed sample.

61
Standard Method of Mechanical Analysis of Soils
AASHTO DESIGNATION T88 - 57
1. Scope
This method describes a procedure for the quantitative determination of the distribution
of particles size in soils.
2. Apparatus
The apparatus shall consist of the following:
Balance - A balance sensitive to 0.1gm for weighing small samples; for large samples, the
balance is to be sensitive to within 0.1 percent of the weight of the sample to be tested.
Stirring apparatus - a mechanically operated stirring apparatus consisting of an electric
motor suitability mounted to turn a vertical shaft at a speed not less than 10,000
revolutions per minute without load, a replaceable stirring paddle made of metal, plastic or
hard rubber similar to the design shown in Figure 1, and a dispersion scup conforming to
either of the designs shown in Figure 2.
(Alternate b) Dispersing Device - An air - jet type dispersing device similar to
either of the designs shown in Figure 3.
Hydrometer - A hydrometer of the exact size and shape shown in Figure 4, the body of
which has been blown in a mold to assure duplication of all dimensions, and equipped with
either scale a or scale B. Scale A shall be graduated form -5 to +60 gm of soil per liter, and
hydrometers equipped with this scale shall be identified as 152H. It shall be calibrated on
the assumption that distilled water has a specific gravity of 1.000 at 680F and that the soil
in suspension has a specific gravity of 2.65. Scale B shall be graduated from 0.995 to 1.038
specific gravity and calibrated to read 1.000 in distilled water at 680F (200c). Hydrometers
equipped with this scale shall be identified as 151H.
A glass graduate 18 inches in height, 2 ½ inches in diameter, and graduated for a
volume 1000ml.
Thermometer - A Fahrenheit thermometer accurate to 10F (0.50c).
Sieve - A series of sieves of square mesh woven wire cloth, conforming to the
requirements of standard specifications for sieves for Testing purposes (AASHTO
Designation: M92). The sieves required are as follows:

62
2 inch sieve (50mm)
1 ½ inch sieve (37.5mm)
1 inch sieve (25mm)
¾ inch sieve (20mm)
3/8 inch sieve (10mm)
No. 4 sieve (4.75)
No. 10 sieve (2mm)
No. 40 sieve (0.425)
No. 200 sieve (0.075mm)
Water Bath or Constant Temperature Room
A water bath or constant temperature room for maintaining the soil suspension at
a constant temperature during the hydrometer analysis. A satisfactory water bath
is an insulated than which maintains the suspension at a convenient constant
temperature as near 680F (20.00c) as the room and faucet water temperature will
permit. Such a device is illustrated in Figure 5. In cases where the work is
performed in a room at an automatically controlled constant temperature, the
water bath is not necessary and subsequent reference to a constant temperature
bat shall be interpreted as meaning either a water bath or a constant temperature
room.
Beaker - A beaker of 250 ml Capacity
3. Sample
The sample required for this test shall include all of the material on the No. 10 (2,000
micron) sieve, plus a 60 or 110gm representative portion of the fraction passing the No. 10
sieve, the larger quantity being required only when this fraction is very sandy. These
samples shall be obtained in accordance with the Standard method of Dry Preparation of
Disturbed Soil Samples Test (AASHTO DESIGNATION: T87), or the Standard Method of Wet
Preparation of Disturbed Soil Samples for test (AASHTO DESIGNATION: T146).
4. Sieve Analysis of Fraction Retained on No. 10 sieve
The portion of the sample retained on the No. 10 sieve shall be separated into a series of
sizes by the use of the 2 inch, 1 ½, 1 ½ - inch, 1 - inch, ¾ - inch, 3/8 - inch, and the
No. 4 sieve.

63
The sieving operation shall be conducted by means of a lateral and vertical, accompanied
by jarring action so as to keep the sample moving continuously over the surface of the
sieve. In no case shall fragments in the sample be turned or manipulated through the
sieve by hand. Sieving shall be continued until not more than 1 percent by weight of
the residue passes any sieve during 1 minute when sieving machines are used, their
thoroughness of sieving shall be tested by comparison with hand methods of sieving as
above described.
The portion of the sample retained on each sieve shall be weighed and the weight
recorded although it shall be permissible to record the accumulated weights as the
contents of each successive sieve is added to the fractions previously deposited on the
scales pan.

64
HYDROMETER AND SIEVE ANALYSIS OF FRACTION PASSING
THE NO.10 SIEVE
5. Hygroscopic Moisture
A 10gm portion of the fraction of the sample passing the No.10 sieve shall be used for the
determination of the hygroscopic moisture. The portion of the sample shall be weighed, dried
to constant weight in an oven at 1100c (2300F), weighed, and the results recorded.
6. Dispersion of Soil Sample
Approximately 50 grams of most soil or 100 grams of very sandy soils shall be taken from
the fraction passing the No. 10 sieve by use of a riffle sampler, weighed, placed in a 250ml,
breaker, covered wit 125ml of stock solution of the selected dispersing agent, stirred
thoroughly with a glass rod, and allowed to soak for a minimum of 12 hours. Any of the four
dispersing agents listed in Table 1 may be used.
The stock solution shall be prepared by dissolving the quantity of the salt given in the table
in sufficient distilled water to make a liter of solution. After soaking, the contents of the
beaker shall be washed into one of the dispersion cups shown in Figure 2, distilled water
added until the cup is more than half full, and the contents dispersed for a period of 1
minute in the mechanical stirring apparatus.
7. Alternate Method for Dispersion
The representative soil sample shall be weighed and placed in a 250ml beaker, covered
with 125ml of the stock solution of the selected dispersing agent specified in section 6,
and allowed to soak for a minimum of 12 hours.
The air jet dispersion apparatus shall be assembled as shown in fig 3 without the cover
cap in place. The needle value controlling the fine pressure shall be opened until the
pressure gauge indicates one pound per square inch air pressure. The initial air
pressure is required to prevent the soil water mixture from entering the air - jet
chamber when the mixture is transferred to the dispersion cup. After the apparatus is
adjusted, the soil water mixture shall be transferred from the beaker to the dispersion
cup, using a wash bottle to assist in the transfer operation.

65
The volume of the soil - water mixture in the dispersion cup shall not exceed 250ml. The
cover containing the baffle late shall be placed upon the dispersion cup and the needle
value opened until the pressure gauge reads 20 pounds per square inch. The soil -
water mixture shall be dispersed for 5, 10 or 15 minutes depending upon the plasticity
index of the soil. Soils with a PI of 5 or less shall be dispersed from 5 minutes; soils
with a PI between 6 and 20 for 10 minutes; and soils with a PI greater than 20 for 15
minutes. Soils containing large percentages of mica need be dispersed for 1 minute
only.
After the dispersion period is completed, the needle value shall be closed until the
pressures gauge indicates one pound per square inch. The cover shall be removed and
all adhering soil particles washed back into the dispersion cup. The soil-water
suspension shall then the washed into the 1000ml glass graduate and the needle value
closed.

66
8. Hydrometer Test
After dispersion, the mixture shall be transferred to the glass graduate and distilled
water having the same temperature as the constant temperature bath added until the
mixture attains a volume of 1000ml. The graduate containing the soil suspension shall
then be placed in the constant temperature bat. When the soil suspension attains the
temperature of the bath, the graduate shall be removed and its contents thoroughly
shaken for 1 minute, the palm of the hand being used as a stopper over the mouth of
the graduate.
At the conclusion of this shaking, the time shall be recorded, the graduate placed in the
bat, and readings taken with the hydrometer at the end of 2 minutes. The hydrometer
shall be read at the top of the meniscus formed by the suspension around its stem. If
hydrometer with scale A is used, it shall be read to the nearest 0.5gm/liter. Scale B
shall be read to the nearest 0.0005 specific gravity. Subsequent readings shall be
taken at intervals of 5, 15, 30, 60, 250, and 1440 minutes after the beginning of
sedimentation. Readings of the thermometer placed in the soil suspension shall be
made immediately following each hydrometer reading and recorded.

69
After each reading the hydrometer shall be very carefully removed from the soil
suspension and placed with a spinning motion in a graduate of clean water. About 25
or 30 seconds before the time for a reading, it shall be taken for a clean water, and
slowly immersed in the soil suspension to assure that it comes to rest before the
appointed reading time.
9. Sieve Analysis
At the conclusion of the final reading of the hydrometer, the suspension shall be washed on
a No.200 (74 micron) sieve. That fraction retained on the No.200 sieve shall be dried and a
sieve analysis made, using the following sieves: No.40, No.60 and No. 200.
CALCULATIONS
10.Percentage of Hygroscopic Moisture
The hygroscopic moisture shall be expressed as a percentage of the weight of the oven-dried
soil and shall be determined as follows:
Percentage of hygroscopic moisture = W - W1 x 100
W1
Where W = weight of air - dried soil, and
W1 = weight of oven - dried soil
To correct the weight of the air - dried sample for hygroscopic moisture, the given value shall
be multiplied by the expression.
100 __
100 + percentage of hygroscopic moisture
11.Coarse Material
The percentage of coarse material shall be calculated from the weight of the fractions
recorded during the sieving of the material retained on the No.10 sieve, in accordance
with section 4, and the total weights recorded during the preparation of the sample, in
accordance with the Standard Method of Dry Preparation of Disturbed Samples for
Tests (AASHTO DESIGNATION: 87).
The percentage of coarse material retained on the No.10 sieve shall be calculated as
follows: From the weight of the air - dried total sample, subtract the weight of the air -

70
dried total sample, subtract the weight of the oven - dried fraction retained on the
No.10 sieve. The difference is assumed to equal the weight of the air dried fraction
passing the No.10 sieve (Note 1).
NOTE 1: According to this assumption no hygroscopic moisture is contained in the air
- dried particles retained on the No.10 sieve, when as a matter of fact a small
percentage of moisture may be present in this fraction. This amount of
moisture, compared with that held in the pores of the fraction passing the
No.10 sieve is relatively small. Therefore, any error produced by the
assumption as stated may be considered negligible in amount.
The weight of the fraction passing the No.10 sieve shall be corrected for hygroscopic
moisture as indicated in section 10. To this value shall be added the weight of the oven -
dried fraction retained on the No.10 sieve to obtain the weight of the total test sample
corrected for hygroscopic moisture. The fractions retained on the No.10 and coarser sieves
shall be expressed as percentages of this corrected weight.
12.Percentage of Soil in Suspension
Hydrometer readings made at temperatures other than 680F shall be corrected by
applying the appropriate composite correction from one of the following tables. Tables
151H and 152H list composite correction for hydrometer 151H and 152H to account
for the different dispersing agents, temperature variations from 680F, (20.00c), and
height of meniscus on the stem of hydrometer.
The percentage of the dispersed soil is suspension represented by different corrected
hydrometer readings depends upon both the amount and the specific gravity of the soil
dispersed. The percentage of dispersed soil remaining in suspension shall be calculated
as follows:
For hydrometer 152H, P = Ra x 100
W
Where : p = Finer
R = Corrected hydrometer reading
W = Mass of dry soil
a = Constant depending on the density of the suspension

73
For hydrometer 151H, P = 1606 (R - 1)a x 100
W
Where, P = Percentage of originally dispersed soil remaining in suspension
R = Corrected hydrometer reading
W = Weight in grams of soil originally dispersed minus the hygroscopic
moisture and
a = Constant depending on the density of the suspension.
For an assumed value of G for the specific gravity of the soil, and water density of
1.000 at 680F (20.00c), the value "a" may be obtained by the formula.
A = 2.6500 - 1.000 x G
2.6500 G-1.0
The value of "a", given to two decimal places are shown in table 2.
TABLE 2 - Values of a, for different specific gravities
Specific Gravity, G Constant, a
2.95 0.94
2.85 0.96
2.75 0.98
2.65 1.00
2.55 1.02
2.45 1.05
2.35 1.08
Table 151H and 152H
It is sufficiently accurate for ordinary tests to select the constant for the specific gravity
nearest to that of the particular soil tested.
To convert the percentages of the soil in suspension to percentages of the total test
sample including the fraction retained on the No.10 sieve, the percentage of originally
dispersed soil remaining in suspension shall be multiplied by the expression.
100 - Percentage retained on No.10 sieve
100

74
13.Diameter of soil particles in suspension
The maximum diameter, d, of the particles in suspension, corresponding to the
percentage indicated by a given hydrometer reading, shall be calculated by the use of
stocks' law.
According to stocks law:
d = √ 30nL
980(G - G1)T
Where d = maximum grain diameter in millimeters
N = Coefficient of viscosity of the suspending medium (in the case water)
in poises varies with changes in temperature of the suspending
medium.
L = distance in cm through which soil particles settle in a given period of
time.
T = time in minutes, period of sedimentation
G = specific gravity of soil particles and
G1 = specific gravity of the suspending medium (approximately 1.0 for
water)
The maximum grain diameter in suspension for assumed conditions and corresponding
to the periods of sedimentation specified in this procedure are given in Table 3. These
grain diameters shall be corrected for the conditions of test applying the proper
correction factors as described and explained below.
Table 3: Maximum Grain Diameter in Suspension under Assumed Conditions
Time (Min.) Max Grain Diameter (Mm)
2 0.040
5 0.026
15 0.015
30 0.010
60 0.0074
250 0.0036
1440 100015

75
The grain diameters given in Table 3 are calculated according to the following
assumptions:
L, the distance through which the particles fall is constant and equal to 17.5cm
n, the coefficient of viscosity equals 0.01005 poise, that of water at 680F.
G, the specific gravity of the soil is constant and equal to 2.65.
Figure 6
The grain diameter corrected for other than the assumed conditions shall be obtained by
the formula.
D = d' X KL XDGXDa
Where in d = corrected grain diameter in mm
d' = grain diameter obtained from table 2
KL = correction factor obtained from figure 6. When the hydrometer
reading not adjusted for composite correction is used for the ordinate
reading
Kg = correction factor obtained from figure 7A.
Kn = correction factor obtained from figure 7B.
The coefficient Kg and Ka are independent of the shape and position of the hydrometer
and are as shown in Figures 7A and 7B.
Figure 7A and 7B
14.Fine Sieve Analysis
The percentage of the dispersed soil sample retained on each of the sieves in the sieve
analysis of the material washed on the No.200 shall be obtained by dividing the weight
of fraction retained on each sieve by the over-dry weight of the dispersed soil and
multiplying by 100.
The percentage of the total test sample, including the fraction retained on the No.10
(2000 microns) sieve, shall be obtained by multiplying these values by the expression.

76
100 minus the percentage retained on No.10 sieve
100

78
15. Plotting
The accumulated percentages of grains of different diameters shall be plotted on semi
logarithmic paper to obtain a "grain size accumulation curve," such as that shown in figure
8.
Figure 8
16. Report
16.1 The results, read from the accumulation curve, shall be reported as follows:
a) Particles larger than 2mm Percent
b) Coarse sand, 2.0 to 0.42mm Percent
c) Fine sand, 0.42 to 0.074mm Percent
d) Silt, 0.074 to 0.005mm Percent
e) Clay, smaller than 0.005mm Percent
f) Colloids, smaller than 0.001mm Percent
16.2 The results complete mechanical analysis furnished by the combined sieve and
hydrometer analysis shall be reported as follows.
SIEVE ANALYSIS
Sieve Size Percent Passing
2inch (50mm)
1 ½ inch (37.5mm)
1 inch (25mm)
¾ inch(20mm)
3/8 inch (10mm)
No.4 (4.75mm)
No.10 (2mm)
No.40 (0.425mm)
No.200 (0.075mm)

79
HYDROMETER ANALYSIS
Smaller than Percent
0.02mm
0.005mm
0.001mm
For materials examined for any particular type of work or purpose, only such fractions
shall be reported as are included in the specification or other requirements for the
work or purpose.

SABA Engineering Plc.
P.O.Box 62668 Addis Ababa, Ethiopia. Tel. 34 10 65/34 16 17/34 30 04 Fax.. 34 12 30/34 16 17
E-mail sava.eng@telecom.net.et
80
Mechanical Analysis
1. Sieve Analysis
Sieve Site
(mm)
Weight
retained gm
% Retained % Passing
75 -
63.5 -
50 -
37.5 -
25 600 23.83 76
20 480 19.06 57
12.5 360 14.3 43
9.5 278 11.04 32
4.7 260 10.33 21
2 60 2.38 19
Pan 480 19.06
Total 2518 100
2. Specific gravity = 2.67
3. Hygroscopic Moisture
a) Wt. of wet sample = 50
b) Wt. of dry sample = 48
c) % dry sample b/a x 100 = 96
Coputed dry Wt. cxa = 48gm
100
4. Sample Pass 2mm
Sieve Weight Retain % Retained % Passing
0.425 10 20.83 15.0
0.250 8 16.7 12
0.075 6 12.5 9.5

81
2. Hydrometer (152H)
Observed
time
Sedimentation
Min (Elapsed
time)
Hydrometer
Reading
Temp.
0F/0c
Diameter
mm
Corrected
Reading 680F
% finer
P=Ra/w*100
Diameter
mm
0 70
2 27 70 0.0395 20.5 42.52
5 25 70 0.0256 18.5 38.37 0.02
15 23 70 0.0148 16.5 34.22
30 20 71 0.0101 13.7 28.41
60 17 71 0.00692 10.7 22.19 0.005
250 15 71 0.00354 8.7 18.04 0.002
1440 12 70 0.00144 5.5 11.41 0.001
3. Report
A B
1. Particles larger than 4.75mm 76% b. Smaller than % passing
2. Coarse sand 4.75-0.425mm 10% 0.02mm 7.2
3. Fine sand 0.425-0.075mm 5% 0.005mm 4.2
4. Silt 0.075-0.002mm 6.50% 0.001mm 2.2
5. Clay smaller than 0.002mm 2.50%

83
SPECIFIC GRAVITY OF SOILS
AASHTO DESIGNATION: T 100 - 75 (1982)
(ASTEM DESIGNATION: d 854 - 58 (1972))
1. SCOPE
1.1This method of test is intended for determining the specific gravity of soils by means of a
pycnometer. When the soils is composed of particles larger than the 4.75mm (No.4)
sieve, the method outlined in the Standard Method of Test for Specific Gravity and
Absorption of Coarse Aggregate (AASHTO T 85) shall be followed. When the soil is
composed of particles both large and smaller than the 4.75mm sieve, the sample shall be
separated on the 4.75mm sieve and the appropriate method of test used on each portion.
The specific gravity value for the soil shall be the weighted average of the two values.
When the specific gravity value is to be used in calculations in connection with the
hydrometer portion of the Standard Method of Mechanical Analysis of Soils (AASHTO 88)
it is intended that the specific gravity test be made on that portion of the soil which
passes the 2.00mm (No.10) or 0.425mm (No.40) sieve, as appropriate.
2. DEFINITION
2.1Specific Gravity - Specific gravity is the ration of the mass in air of a given volume of a
material at a stated temperature to the mass in air of an equal volume of distilled water
at a stated temperature.
3. APPARATUS
The apparatus shall consist of the following:
Pycnometer - Either a volumetric flask having a capacity of at least 100ml or a
stoppered bottle having a capacity of at least 50ml (Note 1). The stopper shall be
of the same material as the bottle, and of such size and shape that it can be easily
inserted to a fixed depth in the neck of the bottle, and shall have a small hole
through its center to permit the emission of air and surplus water.
Note 1 - The use of either the volumetric flask or the stoppered bottle is a matter
of individual preference, but in general, the flask should be used when a larger
sample that can be used in the stoppered bottle is needed due to maximum grain
size of the sample.

84
Balance - Either a balance sensitive to 0.01g for use with the volumetric flask,
or a balance sensitive to 0.001g for use with the stoppered bottle.
Desiccator - A desiccator, about 8 in. (approximately 200mm) in diameter
containing anhydrous sillca gel or other suitable desiccant.
Oven - A thermostatically controlled drying over capable of maintaining a
temperature of 110±5c (230±90F).
Thermometer - A thermometer covering the range of 0-500c (32 - 1220F),
readable and accurate to 10c (20F).
4. GENERAL REQUIREMENTS FOR WEIGHING
4.1When the volumetric flask is used in the specific gravity determination all masses shall
be determined to the nearest 0.01g. When the stoppered bottle is used in the specific
gravity determination all masses shall be determined to the nearest 0.001g.
5. CALIBRATION OF PYCNOMETER
The pycnometer shall be cleaned, dried, weighed, and the mass recorded. The
pycnometer shall be filled with distilled water (Note 2) essentially at room temperature.
The mass of the pycnometer and water, Wa, shall be determined and recorded. A
thermometer shall be inserted in the water and its temperature Ti determined to the
nearest whole degree.
NOTE 2 - Kerosene is a better wetting agent than water for most soils and may be used
in place of distilled water for oven - dried samples.
From the mass W1 determined at the observed temperature Ti a table of vales of masses
Wa shall be prepared for a series of temperatures that are likely to prevail when
masses Wb are determined later (Note 3). These values of Wa shall be calculated as
follows:
Wa (at Tx) = density of water at Tx X (Wa (at Ti) - Wf) + Wf
Density of water at Ti
Wa = mass of the pycnometer and water, in grams
Wf = mass of pycnometer, in grams
Ti = observed temperature of water, in degrees Celsius, and
Tx = any other desired temperature, in degrees Celsius.

85
NOTE 3 - The method provides a procedure that is most convenient for laboratories
making many determinations with the same pycnometer. If no equally applicable to a
single determination, bringing the pycnometer and contents to some designated
temperature when masses Wa and Wb are taken, requires considerable time. It is
much more convenient to prepare a table of masses Wa for various temperatures likely
to prevail when masses Wb are taken. It is important that masses Wa and Wb be based
on water at the same temperature. Values for the relative density of water at
temperatures form 18 to 300c are given in table 1.
6. SAMPLE
The soil to be used in the specific gravity test may contain its natural moisture or be
oven - dried. The mass of the test sample on an oven - dry basis shall be at least 25g
when the volumetric flask is to be used, and at least 10g when the stoppered bottle is
to be used.
Samples containing natural moisture - When the sample contains its natural moisture,
the mass of the soil, Wo, on an oven - dry basis shall be determined at the end of the
test by evaporating the water in an oven maintained at 110±50c (230±90F) (Note 4).
Samples of clay soils containing their natural moisture content shall be dispersed in
distilled water before placing in the flask, using the dispersing equipment specified in
AASHTO T 88.
Oven - Dried Samples - When an oven - dried sample is t be used, the sample shall be
dried for at least 12h, or to constant mass Vo±50c (230±90F) (Note 4), transferred to
pycnometer and weighed. The sample shall then be soaked in distilled water for at least
12h.
NOTE 4 - Drying of certain soils at 1100c may bring about loss of moisture of
composition or hydration, and in such cases drying shall be done, if desired, in
reduced air pressure and at a lower temperature.
7. PROCEDURE
The sample containing natural moisture shall be placed in the pycnometer, care being
taken not to lose any of the soil in case the mass of the sample has been determined.
Distilled water shall be added to fill the volumetric flask about three - fourths full on
the stoppered bottle about half full.
Entrapped air shall be removed by either of the following methods:

86
1. By subjecting the contents to a partial vacuum (air pressure not exceeding 100mm
of mercury) or
2. By boiling gently for at least 10min. while occasionally rolling the pycnometer to
assist in the removal of the air. Subjection of the contents to reduced air pressure
may be done either by connecting the pycnometer directly to an aspiration or
vacuum pump, or by use of a bell jar. Some soils boil violently when subjected to
reduced air pressure. It will be necessary in those cases to reduce the air pressure
at a slower rate or to use a larger flask samples that are heated shall be cooled to
room temperature.
The pycnometer shall then be filled with distilled water and the outside cleaned and
dried with a clean dry cloth. The mass of the pycnometer and contents, Wb, and the
temperature in degrees Celsius, Tx, of the contents shall be determined, as described
in section 4. (Note 5)
NOTE 5 - The minimum volume of slurry that can be prepared by dispersing
equipment specified in AASHTO T88 is such that a 500ml flask is needed as
pycnometer.
8. CALCULATION AND REPORT
8.1 The specific gravity of the soil, based on water at a temperature Tx, shall be calculated
as follows:
Specific Gravity, Tx/TxC = Wo
Wo + (Wa + Wb)
Where Wa = mass of sample of oven - dry soil, in grams
Wa = mass of pycnometer filled with water at temperature Tx (Note 6), in grams
Wb = mass of pycnometer filled with water and soil at temperature Tz, in grams and
Tx = temperature of the contents of the pycnometer when weight Wb, was
determined, in degrees Celsius.
NOTE 6 - This value shall be taken from the table of values of Wa prepared in
accordance with 5.1 for the temperature prevailing when mass Wb was taken.
8.2 Unless otherwise required, specific gravity values reported shall be based on water at
200c. The value based on water at 200c shall be calculated from the value based on
water at the observed temperature Tx, as follows:

87
Specific gravity, Tx/200c = KX specific gravity, Tx/Tx0c, where:
K = a number found by dividing the relative density of water at temperature Tx by the
relative density of water at 200c. Values for a range of temperatures are given in Table
1.
8.3 When it is desired to report the specific gravity value based on water at 40c, such a
specific gravity value may be calculated by multiplying the specific gravity value at
temperature Tx by the relative density of water at temperature Tx.
8.4 When any portion of the original sample of soil is eliminated in the preparation of the
test sample, the portion of which the test has been made shall be reported.
Table 1 Relative Density of water and conversion factor K for various temperatures
Temperature,
0c
Relative Density of
Water
Correction Factor K
18 0.9986244 1.0004
19 0.9984347 1.0002
20 0.9982343 1.0000
21 0.9980233 0.9998
22 0.9978019 0.9996
23 0.9975702 0.9993
24 0.9973286 0.9991
25 0.9970770 0.9989
26 0.9968156 0.9986
27 0.9965451 0.9983
28 0.9962652 0.9980
29 0.9956761 0.9977
30 0.9956780 0.9974

88
Specific Gravity - Calculation of Soil
Bottle No. A B
W1 - Weight of Bottle 16 18
W2 - Weight of Sample 10 10
W3 - Weight of bottle + sample + water 40.2 40.3
W4 - Weight of Bottle full of Water 34 34.1
V - Volume of bottle (W4 + W2) - W3 3.8 3.8
GS - Specific Gravity W2
V
2.632 2.632

89
SECTION II
I. Moisture - Density Relationship
Theory
Compaction (degree of compaction)
Soil is the process where by soil particles are constrained to pack more closely together
through a reduction in air voids. The object in compacting soil is to improve its
properties and in particular to increase its strength and bearing capacity reduce its
compressibility and decrease its ability absorb water due to reduction in volume of voids.
Development of test procedures by R.R. proctor in 1993 in the USA in order to
determine a satisfactory state of compaction for soils being used in the construction of
roads air ports and dams. The test made use of a hand rammer and a cylindrical mold
with a volume of 1/30 cuff. At that time it was believed that the proctor test represented
in the laboratory the state of compaction which could be reasonably achieved in the field.
A laboratory test using increased energy of compaction was then necessary to reproduce
these higher compacted densities, so a test was introduced which used a heavier rammer
with the same mold. These procedures became known as the modified AASHTO T-180
test.
1. DEFINITIONS of the following
a. Compaction:- The process of packing soil particles more closely together, usually by
rolling, ramming or mechanical means, thus increasing the dry density of soil.
b. Moisture - Dry density relationship:- The relationship between dry density and
moisture content of a soil.
c. Optimum Moisture Content (OMC):- The moisture content of a soil at which a
specified amount of compaction will produce the max. dry density.
d. Max. dry density:- the dry density optioned using a specified amount of compaction
at eh Opt. M. C.
e. Percentage air void ( va):- the volume of air voids in a soil expressed as a
percentage.
f. Saturation line (zero air voids line):- the line on a graph showing the dry density-
moisture content relationship for a soil compacting no air voids.
g. Relative compaction (% (compaction):- the percentage ratio of the dry density of
the soils to its max compacted dry density determined by using a specified amount of
compaction (Lab max dry density and field dry density.

90
h. Standard proctor:- light compaction, for light traffic road compaction by using 5.5 lb
rammer and 3 layer compaction.
i. Modified proctor:- heavy compaction for heavy Load construction (axle load)
compaction by using 10 lb rammer and 5 layer compaction.
2. Compaction Process:- the solid soil particles are paced more closely together by
mechanical means. This process must not be confused with consolidation, in which
water is squeezed out under the action of a continuous static load. The air voids can not
be eliminated altogether by compaction, but with proper control they can be reduced for
a minimum. At low moisture content the soil grains are surrounded by a thin film of
water, which tends to keep the grins a part even when compacted. The finer soil grains
the more significant is this effect. If the moisture content is increased the additional
water enables the grains to be more easily compacted together, some of the air is
displaced and the dry density is increased. The addition of more water, up to a certain
point, enables more air to be expelled during compaction. At that point the soil grains
become as closely packed together as they can be (i.e. the dry density is at the
maximum) under the application of this compactive effort when the amount of water
exceeds that required to achieve this condition, the excess water begins to push the
particle apart or water takes more spaces, so that the dry density is reduced. At higher
moisture contents little or no more air is displaced by compaction, and the resulting dry
density continues to decrease.
3. Sample preparation:- the method of preparation of test samples from the original
(received from field) soil sample depends up on.
3.1 The largest size of stone (particles) present in the original sample.
3.2 Whether or not the soil particles are susceptible to crushing during compaction is
assessed by inspection, or by passing the soil through sieves in the gravel-size range
the amount of coarse materials determines the size of mold to be used i.e. whether
4" or 6" dia mold should be used.
If breakdown of particles results in a change in the soil characteristics, and it a single
batch of soil is compacted several times that change will be progressive during the
test. A separate - batch of susceptible soil is needed for each determination of
compacted dry density, consequently a much larger sample is required.

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