UNIVERSITY OF NAIROBI
EFFECT OF QUARRY DUST ON THE PHYSICAL
PROPERTIES OF LATERITIC GRAVEL AS SUBBASE
MATERIAL
BY: ALVIN HABWE WETANGULA, F16/21400/2007
A project submitted as a partial fulfillment for the requirement
for the award of the degree of
BACHELOR OF SCIENCE IN CIVIL ENGINEERING
2015
1
ACKNOWLEDGEMENT
I would like to acknowledge Eng. Elvis Cheruiyot Kipkorir for inspiring me to take this step to
becoming a competent materials Engineer, Prof. Sixtus Kinyua Mwea and Eng. Dionysius Maina
Wanjau for the encouragement that got me this far, Eng. Evans Goro who supervised me and
steered my project in the right direction, and finally to the Lord almighty for getting me through
the Bachelor of science in civil engineering
2
DEDICATION
I dedicate this project to my father and mother who have worked hard and sacrificed to ensure
that I reach this far in life, and to my brothers and sisters who have given me support. Thank you
very much.
3
TABLE OF CONTENTS
ACKNOWLEDGEMENT
DEDICATION
TABLE OF CONTENTS
LIST OF FIGURES
LIST OF TABLES
ABBRIVIATIONS USED
ABSTRACT
CHAPTER ONE
1.0 INTRODUCTION
1.1 SUMMARY
1.1.1 QUARRY DUST
1.1.2 ROAD CLASSIFICATION
1.1.3 EXISTING ROAD CLASSIFICATION
1.1.4 SUB-BASE
1.1.5 LATERITIC GRAVEL
1.2 PROBLEM STATEMENT
1.3 JUSTIFICATION
1.4 OBJECTIVES
1.5 SCOPE
CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 SOIL
2.2 SOIL STABILIZATION
2.2.1 SOIL STABILIZATION METHODS
2.2.1.1 STABILIZATION BY USE OF STABILIZING AGENTS
2.2.1.1.1 CEMENT STABILIZATION
2.2.1.1.2 LIME STABILIZATION
2.2.1.1.3 BITUMINOUS STABILIZATION
2.2.1.2 STABILIZATION BY COMPACTION
2.2.1.3 SOIL STABILIZATION TO CONTROL SHRINK SWELL
2.2.1.4 SOIL STABILIZATION TO REDUCE WATER CONTENT
2.3 QUARRY DUST
2.3.1 PROODUCTION
2.3.2 QUARRY DUST CHARACTERISTICS
2.3.3 EFFECTS OF QUARRY DUST
4
2.3.4
2.3.5
UTILIZATION APPPLICATIONS
OBSTACLES TO UTILIZATION
CHAPTER THREE
3.0 METHODOLOGY
3.1 PREPERATION OF MATERIALS
3.2 PRELIMINARY TESTS
3.2.1 COMPACTION
3.2.2 CALOFORNIA BEARING RATIO
3.2.3 PARTICLE SIZE ANALYSIS OF SOILS
3.2.4 ATTERBERGS LIMITS
CHAPTER FOUR
4.0 RESULTS AND ANALYSIS
4.1 COMPACTION TEST
4.2 CBR TEST
4.3 ATTERBERGS LIMIT TEST
4.4 PARTICLE SIZE DISTRIBUTION TEST
CHAPTER FIVE
5.0 DISCUSSION, CONCLUSION AND RECOMMENDATION
5.1 DISCUSSION
5.2 CONCLUSION
5.3 ECONOMIC JUSTIFICATION
5.4 RECOMMENDATIONS
CHAPTER SIX
6.0 REFFERENCES
LIST OF FIGURES
Figure 1 the different layers of a road
Figure 2 Typical cement stabilization of soil
Figure 3 Typical lime stabilization of soil
Figure 4 Typical bituminous stabilization of soil
Figure 5 Typical Quarry
Figure 6 Typical Quarry Dust
Figure 7 Equipment for standard compaction test
5
Figure 8 CBR loading press
Figure 9 Sieve analysis
Figure 10 Equipment for Atterberg Limits test equipment
CHAPTER ONE
1.0
INTRODUCTION
1.1 Summary
This project comprises of detailed investigation of how quarry dust can be used as a suitable
agent of stabilizing lateritic gravel. A cost evaluation has also been done so as to establish the
cost effectiveness of stabilization with quarry dust.
1.1.1 Quarry Dust
Quarry dust can be defined as residue, tailing or other non-voluble waste material after the
extraction and processing of rocks to form fine particles less than 4.75 mm. It is a waste from
stone crushing units and accounts for about 25% of the final product. Quarry dust which is
released directly into environment can cause environmental pollution. To reduce the impact of
the quarry dust on environment and human, this waste can be used to produce new products or
can be used as admixture in concrete so that the natural resources are used efficiently and hence
environmental waste can be reduced
1.1.2 Road Classification
Road Infrastructure is a key driver to development of Nations. A road classification system has
several purposes which are interrelated. Key among these are:
6

Planning. The application of a road classification provides a framework for policy
formulation in road administration and management. Road classification assists planners
in allocating resources for maintenance and development for the road network between
different groups of roads and also for setting priorities.

Design. A road classification system indicates an expected level of service for specific
road classes and therefore provides guidance to design engineers in applying appropriate
design standards.

Administration. Road classification also clarifies responsibilities amongst road
administrations and the assignment of road sub-networks.

Usage. A well-defined and consistent road classification system influences road user
expectations, behavior and performance in traffic which improves the effectiveness with
which the road network carries traffic. Hence the road classification system should
provide road users with some confidence in the level and continuity of service intended to
be provided.
1.1.3 Existing Road Classification System
CLASS DESCRIPTION
A
FUNCTION
International Trunk Roads Link
centers
of
international
importance
and cross
international boundaries or terminate at international ports
or airports
B
National Trunk Roads
Link nationally important centers
C
Primary Roads
Link provincially important centers to each other or to
higher class roads
D
Secondary Roads
Link
locally important
centers
to
each
other,
or
to more important centers or to a higher class road
7
E
Minor Roads
Any link to a minor center
SPR
G
Government Roads
L
Settlement Roads
R
Rural Access Roads
S
Sugar Roads
T
Tea Roads
W
Wheat Roads
Unclassified
All other public roads and streets
U
The required CBR of the sub-base varies in the different road classes depending on the loading
requirements.
1.1.4 Sub-base
The sub base layer is a critical layer in road construction. This layer acts as the foundation of the
road. It comes between the sub grade and the base. Sub base should be properly designed since it
is the main load bearing layer of a pavement. It is primarily designed to evenly spread the
applied load of the top paving layers and the traffic to the sub grade below. Due to this, proper
design of the sub base will prevent channelization and settlement of the pavement from
occurring. The sub base also protects the base from adverse effects of the sub grade.
There are several materials used in making the sub base; these include graded crushed stones
(GCS) 0/30mm or 0/40 mm, stabilized red soil or gravel. The stabilization can either be
mechanical or chemical. The mechanical stabilization involves addition of milled asphalt,
hoggins, slag, scalping. The chemical stabilization involves addition of cement lime or
pozzolanic ash
8
Figure 1 The different layers of a road
Function of the layers of a road:

Surface - To increase the skid resistance of the road surface

Binder Course - It is designed to reduce rutting and withstand the highest stresses

Asphalt base Course - Providing adequate durability since this layer is not exposed to the
environment.

Base - To redistribute the applied load from the surface course to the sub base

Sub-base and subgrade - Consist of unbound materials, such as indigenous soil, crushed
or uncrushed aggregate, or re-used secondary material and constitute the foundations of
the road structure, and
1.1.5 LATERITIC GRAVEL
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Lateritic gravel is widely used in road construction due to its high strength and low plasticity
compared to other soils. However to improve the properties of the lateritic gravel, stabilization is
done. This lowers the plasticity incase the lateritic gravel contains significant amounts of fines.
Lateritic gravels and laterites are formed through intense leaching of well drained soils under
tropical and sub-tropical climates.
1.2 PROBLEM STATEMENT
The sub-base layer being a very important layer in road construction needs proper design and use
of high quality material. Stabilization using cement and lime has proved to be effective over the
years. However due to the high prices of this stabilizers other methods need to be in co-operated
so as to reduce the cost of stabilization and hence reducing the cost of constructing the road.
There are various cheap methods of stabilizing the soils which are currently used in road
construction.
1.3 JUSTIFICATION
Quarry dust is a waste from stone crushing units and is therefore readily available at an
affordable price. Quarry dust contains non plastic sand particles and will therefore lower the
plasticity index of the gravel. Quarry dust has a higher CBR value than gravel because it is
obtained from crushing stones and would therefore increase the gravels bearing capacity. Quarry
dust contains a lot of fine grained particles and will therefore be within the required grading
curve envelope
1.4 OBJECTIVES
1. To determine the effect of quarry dust on plasticity and shrinkage of lateritic gravel as
sub material
2. To determine the effect of quarry dust on bearing strength of lateritic gravel as sub base
material.
3. To determine the effect of quarry dust on particle size distribution of lateritic gravel as
sub base material.
1.5 SCOPE
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The materials to be used will be locally available materials. The California Bearing Ratio (CBR),
the Attebergs limits and the sieve analysis are the tests which will be conducted to determine the
effect of addition of the quarry dust on physical properties of lateritic gravel. A study of the past
works done by other people will also be used to make references.
CHAPTER TWO
2.0
LITERATURE REVIEW
2.1 SOIL
Soil is unconsolidated mineral and organic matter on the earths surface. Soil comprises of
organic matter, solids and voids. The voids are filled with air and water.
Soil can be organized into the following three basic groups:

Cohesive soils-This are soils which contains silts and clay particles. The particles are
dense and tightly bound together by molecular attraction. They are plastic when wet.

Granular soils-This contains sand particles which ranges from size 0.03 – 0.08 and
medium gravel which ranges from size 0.08 – 1.0.Granular soil is water draining and
obtains maximum dry density (MDD) at either saturated or full dry state.

Organic soils-This is not suitable for compaction and not applicable in engineering.
2.2 SOIL STABILIZATION
Soil stabilization is the alteration of soil properties to improve the engineering performance of
soils. The properties most often altered are density, water content, plasticity and strength. Soil
stabilization is classified into:



Chemical stabilization- this involves the addition of cement or lime
Mechanical stabilization- this is the use of locally available materials such as milled
asphalt, hoggins and slag to achieve the desired soil properties.
Thermal stabilization- this involves heating the soil to be stabilized with some additives
such as cryolite, borax, and glass.
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2.2.1 STABILIZATION METHODS
2.2.1.1 STABILIZATION BY USE OF STABILIZING AGENTS
The incorporation of stabilizing agents, usually in relative low amounts, alters both physical and
chemical properties. Lime and cement as well as bitumen have a wide application.
2.2.1.1.1 CEMENT STABILIZATION
Factors which have made use of Portland cement popular as a stabilizer in the world are: Almost
any soil can be stabilized with Portland cement if enough cement is used in combination with the
right amount of water and proper compaction and curing. More information is available on
cement-treated soil mixtures than other types of soil Stabilization Cement is readily available in
most countries as home product.
Mechanism of cement stabilization
Upon coming into contact with water, the major hydration products of cement are; calcium
silicate hydrates, calcium aluminates hydrates and hydrated lime of which the first two constitute
the major cementitious component while lime is deposited as a separate crystalline solid phase.
When cement is present in granular soil, the cementation is probably very similar to that of
concrete, except that the cement phase does not fill the voids between the soil particles.
Cementation is by means of mechanical bonding of calcium silicate and aluminates hydrates to
the rough mineral surfaces. When cement is used to stabilize fine grained soils, cementation is
both mechanical and chemical bonding involving reaction between the cement and the surfaces
of soil particles. As more cement is added quantity of silt and clay is reduced progressively and
coarse material of lower water retention capacity and volume stability value is obtained: this is a
cement modified soil. As more and more cement is added a quantity of coarse grained material is
increased where all the soil grains remains a solid mass.(S. B. SEHGAL, 1984).
Materials for soil-cement stabilization
Soil, Portland cement, and water are the three basic materials needed to produce soil-cement.
Low cost is achieved mainly by using inexpensive local materials. The soil that makes up the
bulk of soil-cement is either in place or obtained nearby, and the water usually hauled over short
distances.
The quantities of Portland cement and water to be added and the density to which the mixture
must be compacted are determined from tests. The water serves two purposes: It helps to obtain
maximum compaction (density) by lubricating the soil grains and It is necessary for hydration of
the cement that hardens and binds the soil into a solid mass.
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Properly produced soil cement contains enough water for both purposes. The cement could be
almost any type of Portland cement that complies with the requirements of the latest ASTM
(American Safety for Testing and Materials) and AASHTO (American Association of State
Highway and Transportation Officials) Types I (normal) and IA (air entrained) Portland cements
are the most commonly used. The water used in soil-cement should be relatively clean and free
from harmful amounts of alkalis, acid, or organic matter. Water fit to drink is satisfactory.
Sometimes seawater has been used satisfactorily when fresh water has been unobtainable.
Figure 2 Typical cement stabilization of soil
2.2.1.1.2 LIME STABILIZATION
Expansive soils are normally very suitable for lime stabilization. This increases the bearing
capacity and reduces the potential swelling in the top layer of the sub grade. The treated layer is
more impermeable so moisture variations are reduced. When lime is added to plastic material, it
first flocculates the clay and substantially reduces plasticity index. This reduction is time
dependent during the initial weeks, and has the effect of increasing the optimum moisture
content and decreasing the maximum dry density in compaction. The compaction characteristics
are therefore constantly changing with time and delays in compaction causes reduction in density
and consequently reduction in strength and durability. The workability of the soil also improves
as the soil becomes more friable.
Both the ion exchange reaction and the production of cementations materials increase the
stability and reduce the volume change within the clay fraction. The swell may even be reduced
from 7% or 8% to 0.1% by the addition of lime. The production of cementitious material can
continue for some time but the materials and the environment will influence the strength
developed. (ALAN EVERETT, 1981). The reaction between various types of lime can be
represented by:
CaCO3 + heat = CaO + CO2
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This reaction is reversible and it does not occur much below 5000 C and is the basis for the
manufacture of quick lime from chalk or limestone.
CaO + H2O = Ca (OH)2 + heat
Hydrated lime is produced as a result of the reaction of quick lime with water.
Ca(OH)2 + CO2 = CaCO3 + H2O
Hydrated lime will form calcium carbonate upon exposure to air where it reacts with carbon
dioxide present in air.
Figure 3 Typical lime stabilization of soil
2.2.1.1.3 BITUMINOUS STABILIZATION
Bitumen is solid or viscous liquid, which occurs in natural asphalt or can be derived from
petroleum. It has strong adhesive properties and consists essentially of hydrocarbons. In natural
condition it is too viscous to be used for stabilization and has to be rendered more fluidic either
as “cut-back” bitumen or a “bitumen emulsion”. Cut back bitumen is a solution of bitumen in
kerosene or diesel; when solvent evaporates bitumen is deposited. Emulsions are suspensions of
bitumen particles in water; when the emulsion breaks the bitumen is deposited on the material to
be stabilized.
Unlike cement and lime, which reacts chemically with material being stabilized, bitumen acts as
a binding agent, which simply sticks particles together thus preventing water ingress. Bituminous
stabilization is uncommon in areas with high rainfall due to the high level of moisture content in
the soil and addition of further fluids in form of bituminous materials may cause loss of strength.
This is a process where the grading is improved by the incorporation of another material, which
affects only the physical properties of the soil. Unlike stabilization by the incorporation of
stabilizing agents the proportion of material added usually exceeds 10% and may be as high as
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50%.Mechanical stabilization has drawbacks particularly in those countries which have heavy
rainfall or where frost is a problem. Although a mechanically stable material is highly desirable it
cannot always be achieved and even when it can it is often necessary to add a stabilizing agent to
bring about a further improvement in the properties of a material.
Figure 4 Typical bituminous stabilization of soil
2.2.1.2 STABILIZATION BY COMPACTION
This is the process whereby soil particles are constrained to pack more closely together through a
reduction in the amount of air contained in the soil mass. By compacting under controlled
conditions, air voids in well graded soils can almost be eliminated. Compaction is measured
quantitatively in terms of the dry density of soil, which is the mass of solids per unit volume of
soil in bulk. The moisture content of the soil is the mass of water it contains expressed as a
percentage of the mass of the dry soil. The increase in the dry density of the soil produced by
compaction depends mainly on the moisture content of the soil and the amount of compaction
applied. (PHILIP SHERWOOD, 1993).
2.2.1.3 SOIL STABILIZATION TO CONTROL SHRINK SWELL
Many clay soils (plastic soils) undergo extensive volumetric changes when subjected to
fluctuating moisture contents. These volumetric changes if not controlled can lead to movements
in structures and impose loads which can cause premature failure. The plasticity of soils has
historically been quantified by the plasticity index, as determined by ASTM D 4318. Typically
specifications limit the plasticity index of a soil to no more than 10-12 to ensure a stable
material. In general terms, the higher the plasticity index, the higher the potential to shrink or
swell as the soil undergoes moisture content fluctuations. Historically, plastic soils have been
treated with quick lime (CaO) or hydrated lime [Ca(OH)2] to lower their plasticity. The lime
15
chemically reacts with the soil particles, effectively changing the soil grains from clay size (less
than 0.002 mm) to silt size (0.05 to 0.002 mm). The determination of the plasticity index is
geared towards measuring this chemical change in the soil. Therefore, the determination of the
plasticity limits is inappropriate when evaluating the effect of quarry dust on the shrink-swell
characteristics of a soil.
2.2.1.4 SOIL STABILIZATION TO REDUCE WATER CONTENT
Soils must be compacted to their maximum practical density to provide a firm base for overlying
structures. For soils to be compacted the moisture content must be controlled because of the
relationship between and moisture content. If the soil to be compacted is either too wet or too
dry, the moisture content must be adjusted to near optimum to achieve maximum density. If a
soil is too dry, moisture is simply added. If a soil is too wet, the moisture content of the soil must
be lowered of sub grade stability to expedite construction.
2.3 QUARRY DUST
2.3.1 PRODUCTION
Quarry dust is produced from the full range of quarrying activities including:



Extraction - overburden removal, drilling and blasting, loading and hauling
Rock preparation - such as pre-screening and primary crushing and screening
Further processing- secondary, screening and treatment
Figure 5 Typical Quarry
Quarry dust comprises material less than (about) 6 mm generated from any of these activities.
They may be used as specific products (for example, as fine aggregate below 4 mm) or within
16
other aggregate products (for example, as part of the overall grading for a Type 1 sub base).
Quarry dust (that is material less than 6 mm) are an essential part of many aggregate products
and are intentionally produced by quarrying activities in order to provide the required product
grindings. The amount of dust produced during blasting is estimated to be as high as 20% (The
University of Leeds, 2007c)
Figure 6 Typical Quarry Dust
2.3.2 QUARRY DUST CHARACTERISTICS
Different quarries, or activities within the same quarry, may generate a range of quarry dust in
relation to their particle size and composition. For instance, dusts produced from primary
screening may have higher or lower clay content than those produced through tertiary crushing
and screening. Quarry dust is composed of the same mineral substances as the soil and solid rock
from which they are derived, even though changes to their physical and chemical characteristics
may have occurred. Quarry dust by their nature, are usually inert or non-hazardous.
Disaggregation, mixing and moving to different locations, exposure to atmospheric conditions
and to surface or groundwater, as well as segregation and the increase of surface area due to
particle size reduction, may cause physical and chemical transformations with detrimental effects
to the environment (BGS, 2003).
Quarry dust are considered more consistent materials in relation to their composition and particle
size, also over time (temporal variability), they are commonly inert or non-hazardous which
means that their impact to the environment and human health is very low, and they could provide
some degree of security to the end user in terms of stable material supply.
Commonly, the decision making criteria upon which the suitability of quarry dust is determined,
are based on technical specifications and standards or on characterization procedures developed
by end users, such as construction product manufacturers. Therefore, it is end users that define
whether quarry dusts comprise a valuable material. Parameters such as rock type, extraction
17
technique and processing route, affect the generation of quarry dust as well as their end
properties, (for example, composition, particle size and shape).
2.3.3 EFFECTS OF QUARRY DUST
Environmental protection and social responsibility is of vital importance to the quarrying sector
to reduce any adverse consequences (for example, in health and safety) and costs associated with
the production of quarry dust (for example, storage, dealing with arising transport, and handling).
The generation of quarry fines may cause adverse impacts on the environment (such as the local
air, land, water, flora and fauna) and human health, and the mitigation of potential impacts is
mandatory. Commonly, various dust control practices (conventional or alternative) are employed
to minimize the impact of dust generated by quarry activities (Petavratzi et al, 2005; Petavratzi,
2006; EIPPCB, 2006). Health issues and the protection of fauna and flora are addressed through
the management and protection of air quality.The utilization of quarry dust is seen as a way to
minimize the accumulation of unwanted material and at the same time to maximize resource use
and efficiency.
2.3.4 UTILIZATION APPLICATIONS
Various utilization prospects exist for quarry fines, which can broadly be classified into unbound
and bound applications. Both categories of end use may require some degree of processing of the
quarry fines to be undertaken in order to comply with technical specifications. End applications
may be of high or low value, or may require a small or a large volume of quarry fines.
These uses include:






Soil mineralization, compost, artificial soils and remediation.
Site restoration and landscaping.
Road pavements
Embankment construction.
Landfill capping.
Manufactured sand (sand replacement in concrete)
2.3.5 OBSTACLES TO UTILIZATION
Quarry dusts can be suitable materials for a variety of end applications; however, currently their
utilization is not widespread to the level it would have been expected mainly due to reasons
related to the geographical position of quarries. Very often quarries operate in remote location
from potential end users and the cost of material to them includes high transport costs, which
discourages their use. There are occasions where producers of aggregates are not aware of
18
potential utilization routes for their quarry fines in the local area, and these materials remain
unused.
Another major obstacle to utilization is the limited knowledge of exact quantities of quarry fines.
It is recommended that figures on quantities of fines produced, marketed and stockpiled should
be calculated in order to properly evaluate the quantities of quarry fines currently available, and
information that present the geographical distribution of quarry fines, should be compiled to
enable the identification of potential end markets.
Some of the barriers to utilization are related to the location of quarry fines, the limited
awareness of potential markets by aggregate producers, the limited knowledge about quarry
dusts arising and their characteristics, and the absence of fully developed fit for use
specifications for a wide range of end products. Often quarry fines require some degree of
processing before they can be used, which may increase their cost and at the same time requires
suitable infrastructure and equipment to become readily available.
CHAPTER THREE
3.0METHODOLOGY
3.1 PREPARATION OF MATERIALS
The quarry dust was sampled from Kitengela. The parent rock of the dust was established to be
granite rock. The lateritic gravel was also sourced from Kitengela. This was obtained at a depth
of two meters below the ground surface. The sample was a disturbed sample. Ordinary Portland
cement class 32.5 was also used as a stabilizer for comparison purposes. The materials were
blended in the following ratios as tabulated.
STABILIZED
MATERIAL
LATERITIC GRAVEL
LATERITIC GRAVEL
LATERITIC GRAVEL
LATERITIC GRAVEL
LATERITIC GRAVEL
STABILIZER
PERCENTAGE OF STABILIZER
NONE
QUARRY DUST
QUARRY DUST
QUARRY DUST
QUARRY DUST
0
5
10
15
20
LATERITIC GRAVEL
LATERITIC GRAVEL
CEMENT
CEMENT
0.5
2.5
19
The tests described below were all conducted for the tabulated materials.
3.2 PRELIMINARY TESTS
3.2.1 COMPACTION
SIGNIFICANCE OF THE TEST
The compaction test is used to aid in guiding the field compaction of soil so as to develop the
best engineering properties of material. This test is primarily used to determine the MDD and
OMC values of the material. High densities improve the shear strength, elastic modulus and the
permeability of the material decreases. To achieve the high densities ,the material is compacted
at OMC.
The standard moisture test ASTM D 698; AASHTO T99 as conducted in the laboratory uses a
constant compactive effort. This is used to simulate the compaction in the field. Greater
compaction effort will result to an increase in density. However exessive compaction will result
to rigid layer which would start to crack. Also the material would become more plastic with
excessive compaction hence it would start to shear. Basing on this ,the compaction test would
show the best field compaction required which should range from 93% to 105% of the MDD
depending on the layer.
APPARATUS

A metal mould with a detachable base plate and removable collar.

A metal hammer weighing 4.5kg with sleeve to control the specified drop of 30.5cm.

A 19mm BS sieve and metal trays.

A balance, hand tools and straight edge

A sample container

Oven
20

Moisture content dishes

Measuring cylinder and water.
PROCEDURE
As per AASHTO T180 and BS 1924: Part 2:1990
Figure 7 Equipment for standard compaction test
3.2.2 CALIFORNIA BEARING RATIO.
SPECIMEN PREPARATION
21
The lateritic gravel was air dried and the specified percentage of dosage was added to it. The
amount of dosage to be added was calculated in terms of percentage of the dry weight of the
gravel. The specified sample was crushed after the required duration of curing and soaking
elapsed. The crushed sample was then air dried, crushed and sampled for the atterbergs limit test
and particle size distribution.
SIGNIFICANCE OF THE TEST
The CBR value is used to classify sub grade materials into different categories i.e. S1 up to
S6.The classes increases as the CBR value increases. This is used in determining the thickness of
the sub base and the base layers hence the CBR value is very vital in the design of pavements.
Material with high CBR value is desirable.
The CBR test is also used to establish how suitable a material is to be used in construction of
base or sub base layers. Since the CBR value gives the load bearing capacity of a material, it is
hence used to indicate the suitability of the material in layers construction.
APPARATUS






CBR machine
A cylindrical metal mould with detachable base plate, top plate and collar.
Spacer
Rammer
Surcharge weights
Gauges
PROCEDURE
As per ASTM designation, D, 1883 specifications.
22
Figure 8 CBR loading press
3.2.3 PARTICLE SIZE ANALYSIS OF SOILS

Sieve analysis (wet sieving followed by dry sieving)
SIGNIFICANCE OF TEST
The mechanics of the analysis of soil is the determination of percent of individual grain sizes
present in the sample. The results of the tests are of the most value when used for classification
purposes. Quite often it will be found that the lager the grain size the better the engineering
properties. In addition the detrimental capillarity and frost damage are not a problem with course
23
materials, whereas they can be very dangerous with the fine grained silts and clay. Highway
specifications for sub-base and base materials also use the grain size analysis for quality
measurements.
The results of the gradation tests are used to determine the size, percent of course or fines that
are needed for a dense impermeable material. This will hence be achieved by mechanical
stabilization. On occasion, the degree of permeability is estimated on the basis of grain size. The
layered grained soils will readily permit the flow of water than fined grained soils.
APPARATUS

Wet/dry sieving

Set of sieves

A balance accurate to 0.1 grams

Trays

Oven
PROCEDURE
As per BS 1377 specifications.
24
Figure 9 Sieve analysis
3.2.4 ATTERBERGS LIMITS

Liquid limit: AASHTO designation: T89

Plastic limit: AASHTO designation; T90

Plasticity index: AASHTO designation: T90

Shrinkage limit: AASHTO

Plasticity modulus : Plasticity index x percentage passing sieve number 36
SIGNIFICANCE OF THE TEST
The atterbergs limits test consists of liquid limit plastic limit and a value frequently used in
conjunction with these limits is the plasticity index. The engineering properties of soil vary with
the amount of water present. The results of the atterbergs tests are used to differentiate between
25
various states of the soil at different moisture contents. The liquid limit is the moisture at which
the soil changes from plastic state to liquid. The plastic limit is the border between plastic and
semi-solid. The plastic index is the arithmetic difference between the liquid limit and plastic
limits. This can also be obtained by multiplying linear shrinkage and a constant value of 2.13
Low plasticity index indicates a granular soil with little or no cohesion. The atterbergs limits in
the construction of pavements are very vital in that it indicates the shrinkage of the material. A
material having high plasticity index is not suitable in pavement construction since it will suffer
excessive shrinkage in dry conditions and excessive expansion in wet conditions. The effect of
constructing on such material would be cracks on the pavement, settlement of the pavement and
ratting of the road surface.
Another important parameter to consider is the plasticity modulus. This is a product of the
plasticity index and the of fines passing sieve number 36 or 425micr meters.A lower plasticity
modulus is desirable since it indicates that the material has got lower amount of plastic fines and
lower plasticity index.
APPARATUS

Flat glass plate

Cone penetrometer

Two spatulas

Cone cap

A wash bottle

Moisture content dishes
PROCEDURE.
Various methods are used in the determination of the atterbergs limits but in this experiment the
Cone penetrometer approach was used.
26
Figure 10 Equipment for Atterberg Limits test equipment
27
CHAPTER FOUR
4.0 RESULTS AND ANALYSIS
4.1 COMPACTION TEST
28
Dry Density / Optimum Moisture Content Relationship
BS 1377: part 4: 1990
SOURCE
KITENGELA
Description:
NEAT GRAVEL
Date Tested:
Method of Compaction: T180
7/1/2015
Date Sampled:
5/1/2015
Sample No:
PR001
Total mass of sample kg 4.0
Moisture Addition (cc)
500
600
700
800
900
Tin No.
Wgt of Wet Soil + Tin (g)
Wgt of Dry Soil + Tin (g)
Wgt of Water (g)
Wgt of Tin (g)
Wgt of Dry Soil (g)
Moisture Content (%)
Average moisture content (%)
181
129.7
119.3
10.4
76.2
43.1
24.0
24.0
53
148.5
135.6
12.9
86.4
49.2
26.2
26.2
100
141.9
126.9
15.0
75.1
51.8
28.9
28.9
65
167.0
144.5
22.5
72.4
72.1
31.2
31.2
65
156.9
136.3
20.6
75.7
60.6
34.0
34.0
Mass of Mould/ Base/ Soil (g)
Mass of Mould + Base (g) A
Mass of Compacted Soil (g)
Volume of Mould (m 3)
Bulk Density (Kg/m3)
Moisture Content (%)
Dry Density (kg/m 3)
5535
4115
1420
0.001
1485
24.0
1198
5700
4115
1585
0.001
1658
26.2
1314
5825
4115
1710
0.001
1789
28.9
1387
5860
4115
1745
0.001
1825
31.2
1391
5845
4115
1730
0.001
1810
34.0
1351
M ax Dry Density =
1390
kg/m3
Optimum Moisture % =
pmc
0.0
30.4
1450
Dry Density (g / cm 3)
1400
1350
1300
1250
1200
1150
1100
20.0
25.0
30.0
Moisture Content (%)
35.0
29
Dry Density / Optimum Moisture Content Relationship
BS 1377: part 4: 1990
SOURCE
KITENGELA
Description:
0.5% CEMENT STABILIZED GRAVEL
Date Tested:
Method of Compaction: T180
10/1/2015
Date Sampled:
5/1/2015
Sample No:
PR002
Total mass of sample kg 4.0
Moisture Addition (cc)
500
600
700
800
Tin No.
Wgt of Wet Soil + Tin (g)
Wgt of Dry Soil + Tin (g)
Wgt of Water (g)
Wgt of Tin (g)
Wgt of Dry Soil (g)
Moisture Content (%)
Average moisture content (%)
126
289.3
245.0
44.3
101.9
143.1
31.0
31.0
123
287.5
241.5
46.0
106.8
134.7
34.1
34.1
145
278.6
230.3
48.3
101.2
129.1
37.4
37.4
68
252.9
205.8
47.1
88.4
117.4
40.1
40.1
Mass of Mould/ Base/ Soil (g)
Mass of Mould + Base (g) A
Mass of Compacted Soil (g)
Volume of Mould (m 3)
Bulk Density (Kg/m3)
Moisture Content (%)
Dry Density (kg/m 3)
5725
4115
1610
0.001
1684
31.0
1286
5865
4115
1750
0.001
1831
34.1
1365
5880
4115
1765
0.001
1846
37.4
1344
5820
4115
1705
0.001
1783
40.1
1273
M ax Dry Density =
1367
kg/m3
pmc
0.0
Optimum Moisture % =
35.0
1400
Dry Density (g / cm 3)
1375
1350
1325
1300
1275
1250
1225
1200
25.0
27.0
29.0
31.0
33.0
35.0
37.0
39.0
Moisture Content (%)
41.0
43.0
45.0
30
Dry Density / Optimum Moisture Content Relationship
BS 1377: part 4: 1990
SOURCE
KITENGELA
Description:
5% QUARRY DUST STABILIZED GRAVEL
Date Tested:
Method of Compaction: T180
10/1/2015
Date Sampled:
5/1/2015
Sample No:
PR004
Total mass of sample kg 4.0
Moisture Addition (cc)
500
600
700
800
900
Tin No.
Wgt of Wet Soil + Tin (g)
Wgt of Dry Soil + Tin (g)
Wgt of Water (g)
Wgt of Tin (g)
Wgt of Dry Soil (g)
Moisture Content (%)
Average moisture content (%)
50
237.1
208.0
29.1
88.6
119.4
24.4
24.4
201
197.6
170.9
26.7
74.8
96.1
27.8
27.8
95
233.7
201.3
32.4
98.3
103.0
31.5
31.5
227
200.5
169.1
31.4
76.0
93.1
33.7
33.7
216
210.3
174.4
35.9
75.6
98.8
36.3
36.3
Mass of Mould/ Base/ Soil (g)
Mass of Mould + Base (g) A
Mass of Compacted Soil (g)
Volume of Mould (m 3)
Bulk Density (Kg/m3)
Moisture Content (%)
Dry Density (kg/m 3)
5700
4115
1585
0.001
1658
24.4
1333
5800
4115
1685
0.001
1763
27.8
1379
5895
4115
1780
0.001
1862
31.5
1416
5855
4115
1740
0.001
1820
33.7
1361
5810
4115
1695
0.001
1773
36.3
1300
M ax Dry Density =
1420
kg/m3
Optimum Moisture % =
pmc
0.0
30.6
1450
Dry Density (g / cm 3)
1425
1400
1375
1350
1325
1300
1275
1250
1225
1200
20.0
22.0
24.0
26.0
28.0
30.0
32.0
34.0
Moisture Content (%)
36.0
38.0
40.0
31
Dry Density / Optimum Moisture Content Relationship
BS 1377: part 4: 1990
Date Sampled:
5/1/2015
SOURCE
KITENGELA
Sample No:
PR005
Description:
10% QUARRY DUST STABILIZED GRAVEL
Layer:
Date Tested:
Method of Compaction: T180
10/1/2015
Total mass of sample kg 4.0
Moisture Addition (cc)
500
600
700
800
Tin No.
Wgt of Wet Soil + Tin (g)
Wgt of Dry Soil + Tin (g)
Wgt of Water (g)
Wgt of Tin (g)
Wgt of Dry Soil (g)
Moisture Content (%)
Average moisture content (%)
58
258.4
222.8
35.6
89.6
133.2
26.7
26.7
62
239.6
205.7
33.9
90.4
115.3
29.4
29.4
51
205.6
176.4
29.2
90.4
86.0
34.0
34.0
198
241.3
199.2
42.1
81.2
118.0
35.7
35.7
Mass of Mould/ Base/ Soil (g)
Mass of Mould + Base (g) A
Mass of Compacted Soil (g)
Volume of Mould (m 3)
Bulk Density (Kg/m3)
Moisture Content (%)
Dry Density (kg/m 3)
5800
4115
1685
0.001
1763
26.7
1391
5915
4115
1800
0.001
1883
29.4
1455
5900
4115
1785
0.001
1867
34.0
1394
5850
4115
1735
0.001
1815
35.7
1338
M ax Dry Density =
1455
kg/m3
Optimum Moisture % =
pmc
0.0
30.0
1500
1475
Dry Density (g / cm 3)
1450
1425
1400
1375
1350
1325
1300
1275
1250
1225
1200
25.0
30.0
35.0
Moisture Content (%)
40.0
32
Dry Density / Optimum Moisture Content Relationship
BS 1377: part 4: 1990
SOURCE
KITENGELA
Description:
15% QUARRY DUST STABILIZED GRAVEL
Date Tested:
Method of Compaction: T180
10/1/2015
Date Sampled:
5/1/2015
Sample No:
PR006
Total mass of sample kg 4.0
Moisture Addition (cc)
500
600
700
800
Tin No.
Wgt of Wet Soil + Tin (g)
Wgt of Dry Soil + Tin (g)
Wgt of Water (g)
Wgt of Tin (g)
Wgt of Dry Soil (g)
Moisture Content (%)
Average moisture content (%)
106
249.6
224.2
25.4
106.4
117.8
21.6
21.6
222
227.3
196.6
30.7
75.6
121.0
25.4
25.4
195
213.8
183.6
30.2
75.0
108.6
27.8
27.8
184
205.2
173.3
31.9
75.3
98.0
32.6
32.6
Mass of Mould/ Base/ Soil (g)
Mass of Mould + Base (g) A
Mass of Compacted Soil (g)
Volume of Mould (m 3)
Bulk Density (Kg/m3)
Moisture Content (%)
Dry Density (kg/m 3)
5800
4115
1685
0.001
1763
21.6
1450
5905
4115
1790
0.001
1872
25.4
1493
5950
4115
1835
0.001
1919
27.8
1502
5870
4115
1755
0.001
1836
32.6
1385
M ax Dry Density =
1502
kg/m3
Optimum Moisture % =
pmc
0.0
27.4
1550
Dry Density (g / cm 3)
1525
1500
1475
1450
1425
1400
1375
1350
1325
1300
20.0
25.0
30.0
Moisture Content (%)
35.0
33
Dry Density / Optimum Moisture Content Relationship
BS 1377: part 4: 1990
SOURCE
KITENGELA
Description:
20% QUARRY DUST STABILIZED GRAVEL
Date Tested:
Method of Compaction: T180
10/1/2015
Date Sampled:
5/1/2015
Sample No:
PR007
Total mass of sample kg 4.0
Moisture Addition (cc)
500
600
700
800
Tin No.
Wgt of Wet Soil + Tin (g)
Wgt of Dry Soil + Tin (g)
Wgt of Water (g)
Wgt of Tin (g)
Wgt of Dry Soil (g)
Moisture Content (%)
Average moisture content (%)
181
225.8
199.0
26.8
76.2
122.8
21.8
21.8
53
284.4
244.9
39.5
87.8
157.1
25.1
25.1
100
232.3
206.0
26.3
108.3
97.7
26.9
26.9
65
251.6
212.6
39.0
86.3
126.3
30.9
30.9
Mass of Mould/ Base/ Soil (g)
Mass of Mould + Base (g) A
Mass of Compacted Soil (g)
Volume of Mould (m 3)
Bulk Density (Kg/m3)
Moisture Content (%)
Dry Density (kg/m 3)
5875
4115
1760
0.001
1841
21.8
1511
5960
4115
1845
0.001
1930
25.1
1542
5975
4115
1860
0.001
1946
26.9
1533
5920
4115
1805
0.001
1888
30.9
1443
M ax Dry Density =
1542
kg/m3
Optimum Moisture % =
pmc
0.0
25.1
1550
Dry Density (g / cm 3)
1525
1500
1475
1450
1425
1400
20.0
25.0
30.0
Moisture Content (%)
35.0
34
MDD AND OMC SUMMARY
SAMPLE NUMBER
PR 001
PR 002
PR 003
PR 004
PR 005
PR 006
PR 007
MDD Kg/m3
DESCRIPTION
NEAT GRAVEL
0.5% CEMENT STABILIZED GRAVEL
2.5% CEMENT STABILIZED GRAVEL
5% QUARRY DUST STABILIZED GRAVEL
10% QUARRY DUST STABILIZED GRAVEL
15% QUARRY DUST STABILIZED GRAVEL
20% QUARRY DUST STABILIZED GRAVEL
1390
1367
1360
1420
1455
1502
1542
OMC %
30.4
35.0
36.2
30.6
30.0
27.4
25.1
MDD COMPARISON
1600
1542
1550
1502
MDD Kg/m3
1500
1455
1450
1400
1420
1390
1367
1360
1350
1300
1250
NEAT
GRAVEL
0.5%
2.5%
5% QUARRY
10%
15%
20%
CEMENT
CEMENT
DUST
QUARRY
QUARRY
QUARRY
STABILIZED STABILIZED STABILIZED
DUST
DUST
DUST
GRAVEL
GRAVEL
GRAVEL STABILIZED STABILIZED STABILIZED
GRAVEL
GRAVEL
GRAVEL
MATERIAL DESCRIPTION
35
OMC COMPARISON
40
36.2
35
30
35.0
30.4
30.6
30.0
27.4
25.1
OMC %
25
20
15
10
5
0
NEAT GRAVEL 0.5% CEMENT 2.5% CEMENT 5% QUARRY 10% QUARRY 15% QUARRY 20% QUARRY
STABILIZED STABILIZED
DUST
DUST
DUST
DUST
GRAVEL
GRAVEL
STABILIZED STABILIZED STABILIZED STABILIZED
GRAVEL
GRAVEL
GRAVEL
GRAVEL
MATERIAL DESCRIPTION
36
4.2 CBR TEST
37
CARLIFORNIA BEARING RATIO TEST
BSC CIVIL ENGINEEING FIFTH YEAR PROJECT
MATERIAL DESCRIPTION: NEAT GRAVEL
SAMPLE NUMBER
DATE SAMPLED
PEN
PR001
10/2/2015
TOP
0
50
100
150
200
250
300
350
400
450
500
DATE TESTED
BOT
0
60
100
130
170
205
230
265
300
335
351
PEN x FCT
0
61
104
152
210
260
300
325
345
355
358
14-2-2015
TOP LOAD BOT LOAD
0.0
0.6
1.3
1.9
2.5
3.2
3.8
4.4
5.1
5.7
6.4
0.0
0.8
1.4
2.0
2.8
3.4
4.0
4.3
4.5
4.7
4.7
0.0
0.8
1.3
1.7
2.2
2.7
3.0
3.5
4.0
4.4
4.6
5.0
4.5
4.0
3.5
LOAD
3.0
2.5
2.0
TOP
BOTTOM
Log. (BOTTOM)
1.5
1.0
0.5
0.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
PENETRATION
PEN
2.5
5.0
TOP READING BOT READING
2.2
3.9
2.8
4.5
TOP CBR
BOT CBR
CBR VALUE
16.62
29.46
21.15
33.99
34%
38
CARLIFORNIA BEARING RATIO TEST
BSC CIVIL ENGINEEING FIFTH YEAR PROJECT
MATERIAL DESCRIPTION: 0.5% CEMENT STABILIZED GRAVEL
SAMPLE NUMBER
DATE SAMPLED
PEN
PR002
10/2/2015
TOP
0
50
100
150
200
250
300
350
400
450
500
DATE TESTED
BOT
0
55
83
115
142
165
198
232
250
266
282
PEN x FCT
0
85
188
266
302
350
372
382
385
24-2-2015
TOP LOAD BOT LOAD
0.0
0.6
1.3
1.9
2.5
3.2
3.8
4.4
5.1
5.7
6.4
0.0
1.1
2.5
3.5
4.0
4.6
4.9
5.0
5.1
0.0
0.7
1.1
1.5
1.9
2.2
2.6
3.1
3.3
3.5
3.7
6.0
5.0
LOAD
4.0
3.0
TOP
BOTTOM
Log. (BOTTOM)
2.0
1.0
0.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
PENETRATION
PEN
2.5
5.0
TOP READING BOT READING
1.8
3.3
3.8
5.1
TOP CBR
BOT CBR
CBR VALUE
13.60
24.92
28.70
38.52
38.5%
39
CARLIFORNIA BEARING RATIO TEST
BSC CIVIL ENGINEEING FIFTH YEAR PROJECT
MATERIAL DESCRIPTION: 2.5% CEMENT STABILIZED GRAVEL
SAMPLE NUMBER
DATE SAMPLED
PEN
PR003
10/2/2015
TOP
0
50
100
150
200
250
300
350
400
450
500
DATE TESTED
BOT
0
64
89
140
205
260
316
384
462
532
537
PEN x FCT
0
105
252
380
490
592
655
730
785
840
870
24-2-2015
TOP LOAD BOT LOAD
0.0
0.6
1.3
1.9
2.5
3.2
3.8
4.4
5.1
5.7
6.4
0.0
1.4
3.3
5.0
6.5
7.8
8.6
9.6
10.3
11.1
11.5
0.0
0.8
1.2
1.8
2.7
3.4
4.2
5.1
6.1
7.0
7.1
14.0
12.0
10.0
LOAD
8.0
6.0
TOP
BOTTOM
Log. (BOTTOM)
4.0
2.0
0.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
PENETRATION
PEN
2.5
5.0
TOP READING BOT READING
2.6
6.0
6.6
10.2
TOP CBR
BOT CBR
CBR VALUE
19.64
45.32
49.85
77.04
77.0%
40
CARLIFORNIA BEARING RATIO TEST
BSC CIVIL ENGINEEING FIFTH YEAR PROJECT
MATERIAL DESCRIPTION: 5% QUARRY DUST STABILIZED GRAVEL
SAMPLE NUMBER
DATE SAMPLED
PEN
PR004
10/2/2015
TOP
0
50
100
150
200
250
300
350
400
450
500
DATE TESTED
BOT
0
90
206
310
400
473
510
PEN x FCT
0
115
231
340
412
520
590
610
14-2-2015
TOP LOAD BOT LOAD
0.0
0.6
1.3
1.9
2.5
3.2
3.8
4.4
0.0
1.2
2.7
4.1
5.3
6.2
6.7
0.0
1.5
3.0
4.5
5.4
6.9
7.8
8.0
9.0
8.0
7.0
6.0
LOAD
5.0
4.0
TOP
BOTTOM
Log. (BOTTOM)
3.0
2.0
1.0
0.0
0.0
1.0
2.0
3.0
4.0
5.0
PENETRATION
PEN
2.5
5.0
TOP READING BOT READING
5.2
5.4
TOP CBR
BOT CBR
39.27
40.79
CBR VALUE
41%
41
CARLIFORNIA BEARING RATIO TEST
BSC CIVIL ENGINEEING FIFTH YEAR PROJECT
MATERIAL DESCRIPTION: 10% QUARRY DUST STABILIZED GRAVEL
SAMPLE NUMBER
DATE SAMPLED
PEN
PR005
10/2/2015
TOP
0
50
100
150
200
250
300
350
400
450
500
DATE TESTED
BOT
0
90
155
210
260
300
340
383
402
430
440
PEN x FCT
0
80
203
292
345
390
420
440
452
462
465
24-2-2015
TOP LOAD BOT LOAD
0.0
0.6
1.3
1.9
2.5
3.2
3.8
4.4
5.1
5.7
6.4
0.0
1.1
2.7
3.8
4.5
5.1
5.5
5.8
6.0
6.1
6.1
0.0
1.2
2.0
2.8
3.4
4.0
4.5
5.0
5.3
5.7
5.8
7.0
6.0
5.0
LOAD
4.0
3.0
TOP
BOTTOM
Log. (BOTTOM)
2.0
1.0
0.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
PENETRATION
PEN
2.5
5.0
TOP READING BOT READING
3.6
5.2
4.5
5.9
TOP CBR
BOT CBR
CBR VALUE
27.19
39.27
33.99
44.56
44.6%
42
CARLIFORNIA BEARING RATIO TEST
BSC CIVIL ENGINEEING FIFTH YEAR PROJECT
MATERIAL DESCRIPTION: 15% QUARRY DUST STABILIZED GRAVEL
SAMPLE NUMBER
DATE SAMPLED
PEN
PR006
10/2/2015
TOP
0
50
100
150
200
250
300
350
400
450
500
DATE TESTED
BOT
0
130
210
275
340
372
404
452
490
530
562
PEN x FCT
0
132
350
445
550
622
650
24-2-2015
TOP LOAD BOT LOAD
0.0
0.6
1.3
1.9
2.5
3.2
3.8
4.4
5.1
5.7
6.4
0.0
1.7
4.6
5.9
7.2
8.2
8.6
0.0
1.7
2.8
3.6
4.5
4.9
5.3
6.0
6.5
7.0
7.4
9.0
8.0
7.0
6.0
LOAD
5.0
4.0
TOP
BOTTOM
Log. (BOTTOM)
3.0
2.0
1.0
0.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
PENETRATION
PEN
2.5
5.0
TOP READING BOT READING
4.4
6.4
7.2
TOP CBR
BOT CBR
CBR VALUE
33.23
48.34
54.38
0.00
54.4%
43
CARLIFORNIA BEARING RATIO TEST
BSC CIVIL ENGINEEING FIFTH YEAR PROJECT
MATERIAL DESCRIPTION: 20% QUARRY DUST STABILIZED GRAVEL
SAMPLE NUMBER
DATE SAMPLED
PEN
PR007
10/2/2015
TOP
0
50
100
150
200
250
300
350
400
450
500
DATE TESTED
BOT
0
68
190
380
435
515
580
655
695
745
750
PEN x FCT
0
64
122
210
330
440
555
640
690
730
747
24-2-2015
TOP LOAD BOT LOAD
0.0
0.6
1.3
1.9
2.5
3.2
3.8
4.4
5.1
5.7
6.4
0.0
0.8
1.6
2.8
4.3
5.8
7.3
8.4
9.1
9.6
9.8
0.0
0.9
2.5
5.0
5.7
6.8
7.6
8.6
9.2
9.8
9.9
12.0
10.0
LOAD
8.0
6.0
TOP
BOTTOM
Log. (BOTTOM)
4.0
2.0
0.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
PENETRATION
PEN
2.5
5.0
TOP READING BOT READING
5.6
9.0
4.4
9.0
TOP CBR
BOT CBR
CBR VALUE
42.30
67.98
33.23
67.98
68.0%
44
CBR SUMMARY
SAMPLE NUMBER
PR 001
PR 002
PR 003
PR 004
PR 005
PR 006
PR 007
DESCRIPTION
CBR %
NEAT GRAVEL
0.5% CEMENT STABILIZED GRAVEL
2.5% CEMENT STABILIZED GRAVEL
5% QUARRY DUST STABILIZED GRAVEL
10% QUARRY DUST STABILIZED GRAVEL
15% QUARRY DUST STABILIZED GRAVEL
20% QUARRY DUST STABILIZED GRAVEL
34.0
38.5
77.0
41.0
44.6
54.4
68.0
CBR COMPARISON
90.0
77.0
80.0
68.0
70.0
CBR %
60.0
54.4
50.0
40.0
38.5
41.0
44.6
34.0
30.0
20.0
10.0
0.0
NEAT
GRAVEL
0.5%
2.5%
5% QUARRY
10%
15%
20%
CEMENT
CEMENT
DUST
QUARRY
QUARRY
QUARRY
STABILIZED STABILIZED STABILIZED
DUST
DUST
DUST
GRAVEL
GRAVEL
GRAVEL STABILIZED STABILIZED STABILIZED
GRAVEL
GRAVEL
GRAVEL
MATERIAL DESCRIPTION
45
ANALYSIS OF CBR FOR THE MATERIAL
The CBR test measures the bearing strength of a material. The materials tested gave the results
as tabulated in the summary for CBR.
The CBR of neat gravel gave a CBR value of 34.0%. This is lower than the minimum required
CBR for material to be used for Sub base and base layers of 35% and 60% respectively.
However this material is good enough for sub grade layer. It can be classified as class S6 for
subgrade material. These are materials with CBR of mean greater than 30%. This material is
suitable enough to be used as subgrade layers in Class A roads, airport runways and railways due
to its ability to withstand high imposed loads at the subgrade level.
Stabilization with 0.5 % cement, 5% quarry dust,10% quarry dust and 15% quarry dust improves
the CBR values. However with these percentages of stabilizers, the material does not still qualify
to be used as sub base layer or base layer material since the minimum required CBR for
stabilized sub base and base material is 60% and 100% respectively.
Higher CBR values are achieved when stabilization is done using quarry dust as compared to
cement stabilization.
The highest values of CBR are achieved when stabilization is done using 20% quarry dust and
2.5 % cement. The CBR values achieved are 68% and 77 % respectively. With this amount of
stabilizer the material is sufficient enough to be used as sub base material since the CBR value is
more than 60%, which is the minimum required CBR for stabilized sub base material.
The stabilization of this material to a value of 100% CBR would require high dosage of
stabilizer. It is hence not recommended for use in base construction since it would be
uneconomical to stabilize this material to base quality.
46
4.3 ATTERBERG LIMIT TEST
47
FIFTH YEAR PROJECT
ATTERBERG LIMITS USING CONE PENETROMETER
Lab Ref:
Description:
NEAT GRAVEL
Date Tested:
28/2/2015
Stabilizer content %:
Date Sampled:
26/2/2015
Sample No:
Material Type:
PR001
Source:
NEAT GRAVEL
KITENGELA
(NEAT)
Liquid limit
Test No.
Plastic limit
1
2
3
4
5
6
1
2
15.4
17.0
20.1
22.1
21
46
7
12
JJ
7F
Mass of container and wet soil
61.0
67.1
74.9
82.3
15.4
15.4
Mass of container and dry soil
48.8
52.6
56.6
60.5
13.6
13.6
Mass of container
28.4
28.8
28.2
28.0
8.5
8.5
Mass of moisture
12.2
14.5
18.3
21.8
1.8
1.8
Mass of dry soil
20.4
23.8
28.4
32.5
5.1
5.1
Moisture content
59.8
60.9
64.4
67.1
35.3
35.3
Initial dial reading
Final dial reading
Cone penetration
Container No.
Average
68.0
LINEAR SHRINKAGE (J)
66.0
Moisture Content (%)
35.3
Length of Oven dry sample
127
mm
Initial Length of sample
140
mm
13
mm
% LS ═
9.3
%
PI = LS x 2.13 ═
27.7
64.0
LS =
62.0
60.0
% Ret on 425µm sieve
58.0
15.0
20.0
Penetration
y = 1.0979x +(mm)
42.585
25.0
LIQUID LIMIT %
64.4
PLASTIC LIMIT %
35.3
PLASTICITY INDEX
29.1
48
FIFTH YEAR PROJECT
ATTERBERG LIMITS USING CONE PENETROMETER
Lab Ref:
Date Sampled:
Description:
2/3/2015
Sample No:
0.5% CEMENT STABILIZED GRAVEL
Date Tested:
2/3/2015
Stabilizer content %:
0.5% CEMENT
Material Type:
PR002
Source:
STABILIZED GRAVEL
Liquid limit
Test No.
KITENGELA
Plastic limit
1
2
3
4
5
6
1
2
15.1
17.4
20.3
22.4
27
18
38
32
4R
W
Mass of container and wet soil
54.8
64.8
72.9
78.9
15.9
15.9
Mass of container and dry soil
45.6
52.0
55.9
59.1
14.0
13.9
Mass of container
27.3
28.7
27.6
28.6
8.0
7.9
Mass of moisture
9.2
12.8
17.0
19.8
1.9
2.0
Mass of dry soil
18.3
23.3
28.3
30.5
6.0
6.0
Moisture content
50.3
54.9
60.1
64.9
31.7
33.3
Initial dial reading
Final dial reading
Cone penetration
Container No.
Moisture Content (%)
Average
68.0
66.0
64.0
62.0
60.0
58.0
56.0
54.0
52.0
50.0
48.0
46.0
44.0
42.0
40.0
15.0
32.5
LINEAR SHRINKAGE (J)
Length of Oven dry sample
128.5
mm
140
mm
11.4
mm
% LS ═
8.1
%
PI = LS x 2.13 ═
24.3
Initial Length of sample
LS =
% Ret on 425µm sieve
20.0
Penetration
(mm)
y = 1.9731x
+ 20.455
25.0
LIQUID LIMIT %
60.0
PLASTIC LIMIT %
31.8
PLASTICITY INDEX
28.2
49
FIFTH YEAR PROJECT
ATTERBERG LIMITS USING CONE PENETROMETER
Lab Ref:
Date Sampled:
Description:
26/2/2015
Sample No:
5% QUARRY DUST STABILIZED GRAVEL
Material Type:
Date Tested:
28/2/2015
Stabilizer content %:
5% QUARRY DUST
PR004
Source:
STABILIZED GRAVEL
Liquid limit
Test No.
KITENGELA
Plastic limit
1
2
3
4
5
6
1
2
15.6
17.6
20.3
22.3
2
24
38
1
MA
O
Mass of container and wet soil
52.4
58.6
67.5
76.9
17.0
17.0
Mass of container and dry soil
43.6
47.2
52.2
58.1
14.8
14.8
Mass of container
28.2
27.8
27.5
29.1
8.6
8.7
Mass of moisture
8.8
11.4
15.3
18.8
2.2
2.2
Mass of dry soil
15.4
19.4
24.7
29.0
6.2
6.1
Moisture content
57.1
58.8
61.9
64.8
35.5
36.1
Initial dial reading
Final dial reading
Cone penetration
Container No.
Average
66.0
LINEAR SHRINKAGE (J)
Length of Oven dry sample
64.0
Moisture Content (%)
35.8
128.5
mm
140
mm
11.5
mm
% LS ═
8.2
%
PI = LS x 2.13 ═
24.5
Initial Length of sample
62.0
LS =
60.0
58.0
% Ret on 425µm sieve
56.0
15.0
20.0
Penetration (mm)
25.0
LIQUID LIMIT %
62.0
PLASTIC LIMIT %
35.8
PLASTICITY INDEX
26.2
y = 1.1513x + 38.852
50
FIFTH YEAR PROJECT
ATTERBERG LIMITS USING CONE PENETROMETER
Lab Ref:
Date Sampled:
Description:
26/2/2015
Sample No:
10% QUARRY DUST STABILIZED GRAVEL
Material Type:
Date Tested:
28/2/2015
Stabilizer content %:
10% QUARRY DUST
PR005
Source:
STABILIZED GRAVEL
Liquid limit
Test No.
KITENGELA
Plastic limit
1
2
3
4
5
6
1
2
15.3
17.3
20.0
22.2
32
13
11
41
4R
W
Mass of container and wet soil
65.8
72.4
79.9
86.3
16.2
16.3
Mass of container and dry soil
52.5
56.7
60.6
64.4
14.4
14.3
Mass of container
28.6
29.1
28.5
28.8
8.8
8.8
Mass of moisture
13.3
15.7
19.3
21.9
1.8
2.0
Mass of dry soil
23.9
27.6
32.1
35.6
5.6
5.5
Moisture content
55.6
56.9
60.1
61.5
32.1
36.4
Initial dial reading
Final dial reading
Cone penetration
Container No.
Average
62.0
LINEAR SHRINKAGE (J)
Length of Oven dry sample
Moisture Content (%)
34.3
128.5
mm
60.0
140
mm
11.2
mm
% LS ═
8.0
%
PI = LS x 2.13 ═
23.9
Initial Length of sample
LS =
58.0
56.0
% Ret on 425µm sieve
54.0
15.0
20.0
y = 0.8969x + 41.772
Penetration (mm)
25.0
LIQUID LIMIT %
59.6
PLASTIC LIMIT %
34.3
PLASTICITY INDEX
25.3
51
FIFTH YEAR PROJECT
ATTERBERG LIMITS USING CONE PENETROMETER
Lab Ref:
Date Sampled:
Description:
28/2/2015
Sample No:
15% QUARRY DUST STABILIZED GRAVEL
Material Type:
Date Tested:
28/2/2015
Stabilizer content %:
15% QUARRY DUST
PR006
Source:
STABILIZED GRAVEL
Liquid limit
Test No.
KITENGELA
Plastic limit
1
2
3
4
5
6
1
2
15.5
17.3
20.0
22.5
26
27
6
35
AK
BX
Mass of container and wet soil
59.4
67.7
73.2
84.3
13.6
13.5
Mass of container and dry soil
49.2
53.6
57.6
63.8
12.2
12.2
Mass of container
29.3
27.3
29.3
29.3
8.0
7.9
Mass of moisture
10.2
14.1
15.6
20.5
1.4
1.3
Mass of dry soil
19.9
26.3
28.3
34.5
4.2
4.3
Moisture content
51.3
53.6
55.1
59.4
33.3
30.2
Initial dial reading
Final dial reading
Cone penetration
Container No.
Average
61.0
LINEAR SHRINKAGE (J)
59.0
Moisture Content (%)
31.8
Length of Oven dry sample
128.5
mm
57.0
140
mm
11.4
mm
% LS ═
8.1
%
PI = LS x 2.13 ═
24.3
Initial Length of sample
55.0
LS =
53.0
51.0
49.0
47.0
45.0
15.0
% Ret on 425µm sieve
20.0
Penetration
(mm)
y = 1.095x + 34.239
25.0
LIQUID LIMIT %
56.0
PLASTIC LIMIT %
31.8
PLASTICITY INDEX
24.2
52
FIFTH YEAR PROJECT
ATTERBERG LIMITS USING CONE PENETROMETER
Lab Ref:
Date Sampled:
Description:
28/2/2015
Sample No:
20% QUARRY DUST STABILIZED GRAVEL
Material Type:
Date Tested:
28/2/2015
Stabilizer content %:
20% QUARRY DUST
PR007
Source:
STABILIZED GRAVEL
Liquid limit
Test No.
KITENGELA
Plastic limit
1
2
3
4
5
6
1
2
15.5
17.6
20.2
22.8
31
48
30
10
A1
Q
Mass of container and wet soil
56.3
63.9
74.6
81.2
16.5
16.6
Mass of container and dry soil
48.0
52.2
57.8
61.3
14.6
14.7
Mass of container
28.7
28.8
28.1
28.7
8.9
8.8
Mass of moisture
8.3
11.7
16.8
19.9
1.9
1.9
Mass of dry soil
19.3
23.4
29.7
32.6
5.7
5.9
Moisture content
43.0
50.0
56.6
61.0
33.3
32.2
Initial dial reading
Final dial reading
Cone penetration
Container No.
Average
64.0
32.8
LINEAR SHRINKAGE (J)
62.0
Moisture Content (%)
60.0
Length of Oven dry sample
128.5
mm
58.0
140
mm
11.2
mm
% LS ═
8.0
%
PI = LS x 2.13 ═
23.9
Initial Length of sample
56.0
54.0
LS =
52.0
50.0
48.0
46.0
44.0
% Ret on 425µm sieve
42.0
40.0
15.0
20.0
y = 2.4614x + 5.8246
Penetration (mm)
25.0
LIQUID LIMIT %
55.0
PLASTIC LIMIT %
32.8
PLASTICITY INDEX
22.2
53
4.4 PARTICLE SIZE DISTRIBUTION (GRADING) TEST
54
PARTICLE SIZE DISTRIBUTION-GRADING
FIFTH YEAR PROJECT
DATE SAMPLED 3/3/15
DATE TESTED 3/3/15
MATERIAL DISCRIPTION
SAMPLE NUMBER
WEIGHT BEFORE WASH
WEIGHT AFTER WASH
NEAT GRAVEL
PR001
SIEVE SIZE UPPER LIMIT LOWER LIMIT
50
37.5
28
20
10
5
2
1
0.425
0.075
100
100
100
100
90
75
50
40
33
20
100
95
80
60
35
20
12
10
7
4
SOURCE
KITENGELA
SIEVE
SIZE
50
28
20
10
5
2.36
1.18
0.6
0.425
0.3
0.15
0.075
less 0.075
wt
retained
0
0
0
0
8.1
18.1
16.8
16.2
9.1
7.1
13.9
8
99.4
wt
passing
100.6
100.6
100.6
100.6
92.5
74.4
57.6
41.4
32.3
25.2
11.3
3.3
200
100.6
% passing
100.00
100.00
100.00
100.00
91.95
73.96
57.26
41.15
32.11
25.05
11.23
3.28
GRADING ENVELOPE
UPPER LIMIT
120
100
% PASSING
80
LOWER LIMIT
60
40
GRADING CURVE
20
0
0
10
20
30
40
50
60
SIEVE SIZE
55
PARTICLE SIZE DISTRIBUTION-GRADING
FIFTH YEAR PROJECT
DATE SAMPLED 3/3/15
DATE TESTED 3/3/15
MATERIAL DISCRIPTION
SAMPLE NUMBER
WEIGHT BEFORE WASH
WEIGHT AFTER WASH
0.5% CEMENT STABILIZED GRAVEL
PR002
SOURCE KITENGELA
SIEVE
SIZE
50
28
20
10
5
2.36
1.18
0.6
0.425
0.3
0.15
0.075
less 0.075
SIEVE SIZE UPPER LIMIT LOWER LIMIT
50
37.5
28
20
10
5
2
1
0.425
0.075
100
100
100
100
90
75
50
40
33
20
100
95
80
60
35
20
12
10
7
4
wt
retained
0
0
0
15.3
11.5
13.7
12
10.7
5.8
5.9
10.8
4
109.3
wt
passing
90.7
90.7
90.7
75.4
63.9
50.2
38.2
27.5
21.7
15.8
5
1
200
90.7
% passing
100.00
100.00
100.00
83.13
70.45
55.35
42.12
30.32
23.93
17.42
5.51
1.10
GRADING ENVELOPE
UPPER LIMIT
120
100
% PASSING
80
LOWER LIMIT
60
40
GRADING CURVE
20
0
0
10
20
30
40
50
60
SIEVE SIZE
56
PARTICLE SIZE DISTRIBUTION-GRADING
FIFTH YEAR PROJECT
DATE SAMPLED 3/3/15
DATE TESTED 3/3/15
MATERIAL DISCRIPTION
SAMPLE NUMBER
WEIGHT BEFORE WASH
WEIGHT AFTER WASH
2.5% CEMENT STABILIZED GRAVEL
PR003
SOURCE KITENGELA
SIEVE
SIZE
50
28
20
10
5
2.36
1.18
0.6
0.425
0.3
0.15
0.075
less 0.075
SIEVE SIZE UPPER LIMIT LOWER LIMIT
50
37.5
28
20
10
5
2
1
0.425
0.075
100
100
100
100
90
75
50
40
33
20
100
95
80
60
35
20
12
10
7
4
wt
retained
0
0
0
26
11
17.5
19.7
17.9
8.3
7.4
12.6
8.1
71.3
wt
passing
128.7
128.7
128.7
102.7
91.7
74.2
54.5
36.6
28.3
20.9
8.3
0.2
200
128.7
% passing
100.00
100.00
100.00
79.80
71.25
57.65
42.35
28.44
21.99
16.24
6.45
0.16
GRADING ENVELOPE
UPPER LIMIT
120
100
% PASSING
80
LOWER LIMIT
60
40
GRADING CURVE
20
0
0
10
20
30
40
50
60
SIEVE SIZE
57
PARTICLE SIZE DISTRIBUTION-GRADING
FIFTH YEAR PROJECT
DATE SAMPLED 3/3/15
DATE TESTED 3/3/15
MATERIAL DISCRIPTION
SAMPLE NUMBER
WEIGHT BEFORE WASH
WEIGHT AFTER WASH
5% QUARY DUST STABILIZED GRAVEL
PR004
SOURCE KITENGELA
SIEVE
SIZE
50
28
20
10
5
2.36
1.18
0.6
0.425
0.3
0.15
0.075
less 0.075
SIEVE SIZE UPPER LIMIT LOWER LIMIT
50
37.5
28
20
10
5
2
1
0.425
0.075
100
100
100
100
90
75
50
40
33
20
100
95
80
60
35
20
12
10
7
4
wt
retained
0
0
0
10.1
6.6
14.6
14.9
14.8
7.8
7.3
13.7
7.8
102
wt
passing
98
98
98
87.9
81.3
66.7
51.8
37
29.2
21.9
8.2
0.4
200
98
% passing
100.00
100.00
100.00
89.69
82.96
68.06
52.86
37.76
29.80
22.35
8.37
0.41
GRADING ENVELOPE
UPPER LIMIT
120
100
% PASSING
80
LOWER LIMIT
60
40
GRADING CURVE
20
0
0
10
20
30
40
50
60
SIEVE SIZE
58
PARTICLE SIZE DISTRIBUTION-GRADING
FIFTH YEAR PROJECT
DATE SAMPLED 3/3/15
DATE TESTED 3/3/15
MATERIAL DISCRIPTION
SAMPLE NUMBER
WEIGHT BEFORE WASH
WEIGHT AFTER WASH
10% QUARY DUST STABILIZED GRAVEL
PR005
SOURCE KITENGELA
SIEVE
SIZE
50
28
20
10
5
2.36
1.18
0.6
0.425
0.3
0.15
0.075
less 0.075
SIEVE SIZE UPPER LIMIT LOWER LIMIT
50
37.5
28
20
10
5
2
1
0.425
0.075
100
100
100
100
90
75
50
40
33
20
100
95
80
60
35
20
12
10
7
4
wt
retained
0
0
0
24.9
5.7
11.3
14.8
15.2
8.1
7.6
12.8
7.8
92.2
wt
passing
107.8
107.8
107.8
82.9
77.2
65.9
51.1
35.9
27.8
20.2
7.4
-0.4
200
107.8
% passing
100.00
100.00
100.00
76.90
71.61
61.13
47.40
33.30
25.79
18.74
6.86
-0.37
GRADING ENVELOPE
UPPER LIMIT
120
100
80
% PASSING
LOWER LIMIT
60
40
GRADING CURVE
20
0
0
-20
10
20
30
40
50
60
SIEVE SIZE
59
PARTICLE SIZE DISTRIBUTION-GRADING
FIFTH YEAR PROJECT
DATE SAMPLED 3/3/15
DATE TESTED 3/3/15
MATERIAL DISCRIPTION
SAMPLE NUMBER
WEIGHT BEFORE WASH
WEIGHT AFTER WASH
15% QUARY DUST STABILIZED GRAVEL
PR006
SOURCE KITENGELA
SIEVE
SIZE
50
28
20
10
5
2.36
1.18
0.6
0.425
0.3
0.15
0.075
less 0.075
SIEVE SIZE UPPER LIMIT LOWER LIMIT
50
37.5
28
20
10
5
2
1
0.425
0.075
100
100
100
100
90
75
50
40
33
20
100
95
80
60
35
20
12
10
7
4
wt
retained
0
0
0
15.7
7.2
15.4
17.6
15.8
8.1
6.7
13.5
8.9
91.5
wt
passing
108.5
108.5
108.5
92.8
85.6
70.2
52.6
36.8
28.7
22
8.5
-0.4
200
108.5
% passing
100.00
100.00
100.00
85.53
78.89
64.70
48.48
33.92
26.45
20.28
7.83
-0.37
GRADING ENVELOPE
UPPER LIMIT
120
100
80
% PASSING
LOWER LIMIT
60
40
GRADING CURVE
20
0
0
-20
10
20
30
40
50
60
SIEVE SIZE
60
PARTICLE SIZE DISTRIBUTION-GRADING
FIFTH YEAR PROJECT
DATE SAMPLED 3/3/15
DATE TESTED 3/3/15
MATERIAL DISCRIPTION
SAMPLE NUMBER
WEIGHT BEFORE WASH
WEIGHT AFTER WASH
20% QUARY DUST STABILIZED GRAVEL
PR007
SOURCE KITENGELA
SIEVE
SIZE
50
28
20
10
5
2.36
1.18
0.6
0.425
0.3
0.15
0.075
less 0.075
SIEVE SIZE UPPER LIMIT LOWER LIMIT
50
37.5
28
20
10
5
2
1
0.425
0.075
100
100
100
100
90
75
50
40
33
20
100
95
80
60
35
20
12
10
7
4
wt
retained
0
0
0
10.5
6.2
20.3
17.6
13.7
6.8
6.4
11.8
8.5
98.5
wt
passing
101.5
101.5
101.5
91
84.8
64.5
46.9
33.2
26.4
20
8.2
-0.3
200
101.5
% passing
100.00
100.00
100.00
89.66
83.55
63.55
46.21
32.71
26.01
19.70
8.08
-0.30
GRADING ENVELOPE
UPPER LIMIT
120
100
80
% PASSING
LOWER LIMIT
60
40
GRADING CURVE
20
0
0
-20
10
20
30
40
50
60
SIEVE SIZE
61
FIFTH YEAR PROJECT
MATERIAL SUMARY FOR GRADING AND ATTERBERGS LIMITS RESULTS
SAMPLE NO MATERIAL DESCRIPTION
% PASSING
SIEVE 0.425
PI
PM
PR001
NEAT GRAVEL
29.1
32.11
934.40
PR002
0.5% CEMENT STABILIZED GRAVEL
28.2
23.93
674.83
PR003
2.5% CEMENT STABILIZED GRAVEL
0
21.99
0.00
PR004
5% QUAEY DUST STABILIZRD GRAVEL
26.2
29.8
780.76
PR005
10% QUAEY DUST STABILIZRD GRAVEL
25.3
25.79
652.49
PR006
15% QUAEY DUST STABILIZRD GRAVEL
24.3
26.45
642.74
PR007
20% QUAEY DUST STABILIZRD GRAVEL
22.2
26.01
577.42
0
1000.00
1
2
3
4
5 CURVE6
PLASTICITY
MODULUS
7
8
1000.00
934.40
900.00
900.00
780.76
PLASTICITY MODULUS
800.00
700.00
800.00
674.83
652.49
700.00
642.74
577.42
600.00
600.00
500.00
500.00
400.00
400.00
300.00
300.00
200.00
200.00
100.00
100.00
0.00
0.00
0.00
PM CURVE
PM GRAPH
MATERIAL TYPE
62
0
1
2
3PLASTICITY
4
5 CURVE6
INDEX
35
30
7
8
35
29.1
28.2
30
26.2
25.3
24.3
25
PI VALUES
22.2
25
20
20
15
15
10
10
5
5
0
NEAT
GRAVEL
0
0
0.5%
2.5%
5% QUAEY 10% QUAEY 15% QUAEY 20% QUAEY
CEMENT CEMENT
DUST
DUST
DUST
DUST
STABILIZED STABILIZED STABILIZRD STABILIZRD STABILIZRD STABILIZRD
GRAVEL
GRAVEL
GRAVEL
GRAVEL
GRAVEL
GRAVEL
MATERIAL DESCRIPTION
PI GRAPH
PI CURVE
63
ANALYSIS OF ATTERBERGS LIMITS AND GRADING TEST
The significance of atterbergs limits test is to show the behavior of the material with changes of
water. This is a key parameter since variation of weather leads to changes in the material. The
change of rainy to sunny seasons leads to expansion and shrinkage of the granular material. The
atterbergs limits test shows clearly how the tested material would behave with these changes.
The neat gravel had a PI of 29.1.Addition of cement led to a decrease in the PI from 29.1 to 28.2
with 0.5 % cement and the material became non plastic with 2.5% cement. This is as a result of
chemical reaction with cement and the clay or plastic particles which in turn reduces the
plasticity.
From the Ministry of Transport and Communication Standard Spec For Road and bridge
construction clause 1203a, the maximum required PI limit for sub base gravel material should be
15%.Thus the neat gravel and 0.5 % stabilization does not meet the requirement. Use of this
material would result to excessive expansion with ingress of water and excessive shrinkage
during dry season. This would result to fatigue and failure of the pavement.
Stabilization using 2.5% cement makes the material non plastic. This is undesirable in pavement
construction since the material would not be easily workable and have less cohesiveness. As a
result of this, the material would not bond perfectly and would tend to shear off while being
compacted.
Stabilization using quarry dust led to decrease in the PI with increase in the quantity of the
quarry dust. This is as a result of addition of quarry dust which is non-plastic hence lowering the
PI of the material. The lowest PI with quarry dust stabilization was achieved with 20% quarry
dust. At this point, a PI value of 22.2 % was obtained. This is also higher than the minimum
required PI value for sub base granular material.
From the same specification, the maximum allowed Plasticity Modulus (PM) is 250.All the
stabilization dosages had PM values more than 250%.This indicated that the material had a lot of
fine plastic particles passing sieve 0.425.Both mechanical and chemical stabilization lowered the
amount of the particles passing sieve 0.425.Stabilization with cement reacted by bonding the
fines particles hence a reduce in the fines while stabilization with quarry dust added more course
material hence lowering the fines quantity.
The neat gravel passed outside the grading envelope for base material as per the roads and bridge
construction hence showing that the material is not good enough to be used as base material. The
grading curve moved outside the upper limit showing lack of sufficient course material. The
curve for the suitable material should move smoothly inside the envelope. Stabilization with both
cement and quarry dust made the material more course. However all the materials lacked
64
material retained at sieve 20 to 37.5.This shows the material is not suitable to be used in base
layer basing on the grading results, since any addition of quarry dust would not improve the lack
of material in sieve 20 to 37.5 and cement stabilization would also not add any significant
material in the same sieve.
65
CHAPTER FIVE
5.0DISCUSSIONS, CONCLUSIONS AND RECOMMENDATIONS
5.1 DISCUSSIONS
66