Fibre Reinforced Soil

WASTE PLASTIC FIBER REINFORCED SOIL
A PROJECT REPORT
Submitted by
ANNIRUTH KANNAN R.U (113211103005)
M. MOHAMMED SHAFIN (113211103045)
R. MADHAVAN (113211103039)
R. RAJKUMAR (113211103070)
In partial fulfilment for the award of the degree
of
BACHELOR OF ENGINEERING
in
CIVIL ENGINEERING
VELAMMAL ENGINEERING COLLEGE, CHENNAI
ANNA UNIVERSITY::CHENNAI 600 025
APRIL 2015

i
ANNA UNIVERSITY: CHENNAI 600 025
BONAFIDE CERTIFICATE
Certified that this project report “WASTE PLASTIC REINFORCED SOIL” is
the bonafide work of “ANNIRUTH KANNAN R.U, M.MOHAMMED
SHAFIN, R.MADHAVAN and R. RAJKUMAR” who carried out the project
work under my supervision.
SIGNATURE SIGNATURE
Dr. R. GANESAN,M.E.,Ph.D. Ms. J. MONSLIN SUGIRTHA,M.E.,
HEAD OF THE DEPARTMENT, ASSISTANT PROFESSOR,
Department of Civil Engineering, Department of Civil Engineering,
Velammal Engineering College, Velammal Engineering College,
Ambattur – Redhills Road Ambattur – Redhills Road,
Surapet, Surapet,
Chennai – 600066. Chennai – 600066.
Submitted for the ANNA UNIVERSITY examination held on
_________________
INTERNAL EXAMINER EXTERNAL EXAMINER

ii
ACKNOWLEDGEMENT
We thank God almighty for giving us strength and courage to
complete this project in the given way and regards are indebted to our parents.
We would like to express our deep gratitude to our beloved
chairman Dr.M.V.Muthuramalingam, Ph.D., and our Chief
Executive Officer, Shri.M.V.M.Velmurugan, M.A., B.L., for their kind
encouragement.
We convey our sincere thanks to our principal, Dr.N.Duraipandian.,
M.E., Ph.D., for extended support for this project.
We extremely grateful to pledge our respect and preferential thanks to our
beloved Head of the Department, Dr.R. Ganesan, M.E., Ph.D., for supporting
and helping us by all means in carrying out this project successfully.
We express our sincere thanks to our project guide Mrs. J. Monslin
Sugirtha Singh, M.E., Assistant Professor for having extended her fullest co-
operation and guidance without which this project would not have been possible.
We are extremely grateful to Mr. T.A. Rajah Rajeshwaran., M.E., Assistant
professor, for arranging soil lab facilities for us. We are extremely grateful to
Dr. R. Sudharsanan, M.E., Ph.D., Assistant Professor, for helping us and
guiding us through difficult situations.
We wish to thank everyone for giving us this opportunity, inspiration and
support for undertaking this project.

iii
ABSTRACT
The main objective of this study is to investigate the use of waste
fiber materials in geotechnical applications and to evaluate the effects of
waste polypropylene fibers on shear strength of unsaturated soil by carrying
out direct shear tests and unconfined compression tests. The results obtained
are compared for various tests and inferences are drawn towards the usability
and effectiveness of fiber reinforcement as a replacement for deep foundation
or raft foundation, as a cost effective approach.
Randomly distributed fiber reinforcement technique has successfully
been used in a variety of applications such as slope stabilization, road subgrade
and sub base etc. This is a relatively simple technique for ground improvement
and has tremendous potential as a cost effective solution to many geotechnical
problem. Keeping this in view the present study was taken up. In this study a
series of compression tests under different confining pressures were conducted
on soil sample without and with plastic reinforcement.
Plastic fibers are similar to the roots of trees and vegetation which
provide an excellent ingredient to improve the soils and the stability of natural
slopes.

iv
TABLE OF CONTENTS
Chapter Contents Page No.
ACKNOWLEDGEMENTS Ii
ABSTRACT iii
TABLE OF CONTENTS Iv
LIST OF TABLES
LIST OF FIGURES AND GRAPHS
V
vi
1. INTRODUCTION
1.1 GENERAL
1.2 WASTE PLASTIC FIBER
1.3 SOIL REINFORCED WITH WASTE PLASTIC
1.4 STABILIZATION
1.5 ADVANTAGES OF SOIL STABILIZATION
1.6 METHODS
1
1
1
2
3
3
4
2. LITERATURE REVIEW
2.1 THE USE OF RE-ENGINEERED WASTE
PLASTICS IN ROAD PAVEMENTS
2.2 USE OF WASTE PLASTICS IN
CONSTRUCTION SECTOR
2.3 USE OF WASTE PLASTIC STRIPS MIXED
WITH SOIL
2.4 USE OF PVC SCRAP AS ALTERNATIVE
BUILDING MATERIAL
2.5 USE OF PLASTIC IN ROAD CONSTRUCTION
6
6
6
7
7
7

v
3. METHODOLOGY
3.1 GENERAL
3.2 TESTS CONDUCTED
9
9
10
4. EXPERIMENTAL INVESTIGATION
4.1 MATERIAL
4.2 PREPARATION OF SAMPLE
4.3 BRIEF TESTS INVOLVED IN EXPERIMENTS
4.3.1 SIEVE ANALYSIS
4.3.2 ATTERBERG’S LIMIT
4.3.3 PARTICLE SIZE DISTRIBUTION
4.3.4 SPECIFIC GRAVITY
4.3.5 SPECIFIC GRAVITY OF SOIL
4.3.6 LIQUID LIMIT
4.3.7 PLASTIC LIMIT
4.3.9 PROCTOR COMPACTION TEST
4.3.10 DIRECT SHEAR TEST
4.3.11 UNCONFINED COMPRESSION TEST
4.3.12 CALIFORNIA BEARING RATIO TEST
11
11
12
12
12
13
13
14
15
16
16
17
17
18
18
19
5. TEST RESULTS AND OBSERVATIONS
5.1 SPECIFIC GRAVITY
5.2 INDEX PROPERTIES
5.2.1 LIQUID LIMIT
5.2.2 PLASTIC LIMIT
5.2.3 PLASTICITY INDEX
20
20
21
21
23
23
24

vi
5.2.5 MOISTURE CONTENT
5.2.5 STANDARD PROCTOR COMPACTION
5.2.8 CALIFORNIA BEARING RATIO
25
26
27
32
40
6. CONCLUSION 41
REFERENCES 43

vii
LIST OF TABLES
Table No. Table Content Page No.
1 Specific Gravity Classification 15
2 Classification of Soil according to Atterberg’s Limit 16
3 Specific Gravity of the Soil Sample 20
4 Liquid Limit of Soil Sample 21
5 Particle Size Distribution 24
6 Moisture Content of Sample 25
7 Standard Procter Test 26
8 Direct Shear Test – Unreinforced Soil 27
9 Direct Shear Test – Reinforced Soil with 0.15%
Plastic Fiber
28
10 Direct Shear Test – Reinforced Soil with 0.25%
Plastic Fiber
29
11 Unconfined Compression Test – Unreinforced Soil 33
12 Unconfined Compression Test – Reinforced Soil
with 0.15% Plastic Fiber
34
13 Unconfined Compression Test – Reinforced Soil
with 0.25% Plastic Fiber
35
14 CBR Soaked Test Soil Sample 37
15 CBR Unsoaked Test Soil Sample 39

viii
LIST OF GRAPHS AND FIGURES
Figure No. Content Page No.
1 Preparation of Plastic Fibers from Waste Plastic
Bottles
11
2 Classification of Soil according to Atterberg’s Limit 16
3 Pyconometer in Specific Gravity Test 20
4 No. of Blows vs. Water Content Graph 21
5 Liquid Limit using Casagrande Apparatus 22
6 Plastic Limit on Glass Plate 22
7 Particle Distribution Graph 24
8 Sieve Shaker Apparatus 25
9 Standard Proctor Apparatus 27
10 DST - Shear Stress vs. Normal Stress Graph for
Unreinforced soil
28
Reinforced Soil with 0.15% Plastic Fibers
29
Reinforced Soil with 0.25% Plastic Fibers
30
13
14
Direct Shear Mould
Direct Shear Apparatus
31
31
15 Unconfined Compression Test Sample and Mould 32
16 UCS – Axial Stress vs. Strain Graph for
Unreinforced Soil
33
17 UCS – Axial Stress vs. Strain Graph for Reinforced
Soil with 0.15% Plastic Fibers
35

ix
18 UCS – Axial Stress vs. Strain Graph for Reinforced
Soil with 0.25% Plastic Fibers
36
19 CBR – Unsoaked - Load vs. Penetration Graph –
Comparison
38
20 CBR – Soaked - Load vs. Penetration Graph –
Comparison
40

x
LIST OF SYMBOLS
NOTATION DESCRIPTION
E Compaction Energy, kJ/m3
OMC Optimum Moisture Content, %
MDD Maximum Dry Density, kN/m3
cu Unit Cohesion, kN/m2
Φ Angle of Internal Friction
UCS Unconfined Compressive Strength
F S Failure Strain, %
S L Strain Level, %
F C Fibre Content, %
B R Bearing Resistance, kN/m2
M.C Moisture Content, %
CBR California Bearing Ratio, %
Es50 Secant Modulus, kN/m2
Ei Initial Tangent Modulus, kN/m2
C‟/C Normalized Cohesion
Cu Coefficient of uniformity
Cc Coefficient of curvature
G Specific Gravity

1
CHAPTER 1
INTRODUCTION
1.1. GENERAL
For any land-based structure, the foundation is very important and has to be
strong to support the entire structure. In order for the foundation to be strong, the soil
around it plays a very critical role. So, to work with soils, we need to have proper
knowledge about their properties and factors which affect their behavior. The process
of soil stabilization helps to achieve the required properties in a soil needed for the
construction work.
From the beginning of construction work, the necessity of enhancing soil
properties has come to the light. Ancient civilizations of the Chinese, Romans and
Incas utilized various methods to improve soil strength etc., some of these methods
were so effective that their buildings and roads still exist.
In India, the modern era of soil stabilization began in early 1970’s, with a
general shortage of petroleum and aggregates, it became necessary for the engineers
to look at means to improve soil other than replacing the poor soil at the building
site. Soil stabilization was used but due to the use of obsolete methods and also due
to the absence of proper technique, soil stabilization lost favor. In recent times, with
the increase in the demand for infrastructure, raw materials and fuel, soil stabilization
has started to take a new shape. With the availability of better research, materials and
equipment, it is emerging as a popular and cost-effective method for soil
improvement.
1.2. WASTE PLASTIC FIBER
The bottled water is the fastest growing beverage industry in the world.
According to the international bottled water association (IBWA), sales of bottled

2
water have increased by 500 percent over the last decade and 1.5 million tons of
plastic are used to bottle water every year. Plastic bottle recycling has not kept pace
with the dramatic increase in virgin resin polyethylene terephthalate (PET) sales and
the last imperative in the ecological triad of reduce / reuse / recycle, has emerged as
the one that needs to be given prominence.
The general survey shows that 1500 bottles are dumped as garbage every
second. PET is reported as one of the most abundant plastics in solid urban waste. In
2007, it was reported that the world’s annual consumption of PET bottles is
approximately 10 million tons and this number grows about up to 15% every year.
On the other hand, the number of recycled or returned bottles is very low. On
an average, an Indian uses one kilogram (kg) of plastics per year and the world
annual average is an alarming 18 kg. It is estimated that approximately 4-5% post-
consumer plastics waste by weight of Municipal Solid Waste (MSW) is generated in
India and the plastics waste generation is more i.e. 6-9 % in USA, Europe and other
developed countries.
1.3. SOIL REINFORCED WITH WASTE PLASTIC
Plastic waste when mixed with soil behaves like a fiber reinforced soil. When
plastic waste/fibers are distributed throughout a soil mass, they impart strength
isotropy and reduce the chance of developing potential planes of weakness. Mixing
of plastic waste fibers with soil can be carried out in a concrete mixing plant or with
a self-propelled rotary mixer. Plastic waste/ fibers could be introduced either in
specific layers or mixed randomly throughout the soil. An earth mass stabilized with
discrete, randomly distributed plastic waste/fibers resembles earth reinforced with
chemical compounds such as lime, cement etc. in its engineering properties.

3
1.4. STABILIZATION
Stabilization can increase the shear strength of a soil and/or control the shrink-
swell properties of a soil, thus improving the load bearing capacity of a sub-grade to
support pavements and foundations. The most common improvements achieved
through stabilization include better soil gradation, reduction of plasticity index or
swelling potential, and increases in durability and strength. In wet weather,
stabilization may also be used to provide a working platform for construction
operations.
These types of soil quality improvement are referred to as soil modification.
Benefits of soil stabilization are higher resistance values, reduction in plasticity,
lower permeability, reduction of pavement thickness, elimination of excavation,
material hauling and handling, and base importation, aids compaction, provides all-
weather access onto and within projects sites.
The determining factors associated with soil stabilization may be the existing
moisture content, the end use of the soil structure and ultimately the cost benefit
provided. As good soil becomes scarcer and their location becomes more difficult
and costly, the need to improve quality of soil using soil stabilization is becoming
more important.
Soil stabilization using raw plastic bottles is an alternative method for the
improvement of subgrade soil of pavement. It can significantly enhance the
properties of the soil used in the construction of road infrastructure.
1.5. ADVANTAGES OF SOIL STABILIZATION
Soil properties vary a great deal and construction of structures depends a
lot on the bearing capacity of the soil, hence, we need to stabilize the soil which
makes it easier to predict the load bearing capacity of the soil and even improve

4
the load bearing capacity. The gradation of the soil is also a very important
property to keep in mind while working with soils. The soils may be well-graded
which is desirable as it has less number of voids or uniformly graded which though
sounds stable but has more voids. Thus, it is better to mix different types of soils
together to improve the soil strength properties. It is very expensive to replace the
inferior soil entirely soil and hence, soil stabilization is important.
 It improves the strength of the soil, thus, increasing the soil bearing capacity.
 It is more economical both in terms of cost and energy to increase the
bearing capacity of the soil rather than going for deep foundation or raft
foundation.
 It is also used to provide more stability to the soil in slopes or other such
places.
 Sometimes soil stabilization is also used to prevent soil erosion or
formation of dust, which is very useful especially in dry and arid weather.
 Stabilization is also done for soil water-proofing; this prevents water from
entering into the soil and hence helps the soil from losing its strength.
 It helps in reducing the soil volume change due to change in
temperature or moisture content.
 Stabilization improves the workability and the durability of the soil.
1.6. METHODS
 Mechanical method of Stabilization
In this procedure, soils of different gradations are mixed together to obtain
the desired property in the soil. This may be done at the site or at some other
place from where it can be transported easily. The final mixture is then
compacted by the usual methods to get the required density.

5
 Additive method of stabilization
It refers to the addition of manufactured products into the soil, which in
proper quantities enhances the quality of the soil. Materials such as cement,
lime, bitumen, fly ash etc. are used as chemical additives. Sometimes different
fibers are also used as reinforcements in the soil. The addition of these fibers
takes place by two methods;
a) Oriented fiber reinforcement
The fibers are arranged in some order and all the fibers are placed in the
same orientation. The fibers are laid layer by layer in this type of orientation.
Continuous fibers in the form of sheets, strips or bars etc. are
used systematically in this type of arrangement.
b) Random fiber reinforcement
This arrangement has discrete fibers distributed randomly in the soil mass.
The mixing is done until the soil and the reinforcement form a more or less
homogeneous mixture. Materials used in this type of reinforcements are
generally derived from paper, nylon, metals or other materials having varied
physical properties. Randomly distributed fibers have some advantages over the
systematically distributed fibers. Somehow this way of reinforcement is similar
to addition of admixtures such as cement, lime etc. Besides being easy to add
and mix, this method also offers strength isotropy, decreases chance of potential
weak planes which occur in the other case and provides ductility to the soil.

6
CHAPTER 2
LITERATURE REVIEW
2.1. THE USE OF RE-ENGINEERED WASTE PLASTICS IN ROAD
PAVEMENTS
Lakshmipathy et.al. (2003)
An experimental investigation to study the suitability of the use of Re-
engineered plastics as fibers for road pavements was performed. The properties
studied include compressive strength, tensile strength, flexural strength under
reversed cyclic loading, impact resistance, plastic shrinkage and abrasion resistance
etc., Efforts have been made to compare it steel fibers. The results have shown that
the improvement of concrete properties at lower cost is obtained with re-engineered
plastic shred reinforced concrete.
2.2. USE OF WASTE PLASTICS IN THE CONSTRUCTION SECTOR
Prabir Das (2004)
It was suggested that plastics can be used in construction industry at various
places. Proper selection of material / grade and suitable design considerations can
help to replace many more applications. Lighter weight, design flexibility, part
integration, low system cost, very high productivity and improved product
appearance are the main features for use of engineering plastics. The engineering
thermoplastics and introduction of application specific grades has thrown challenges
to conventional materials in the industries. This paper provides all the supports in
selecting suitable engineering plastics, process and design for conversion of
conventional material to engineering plastics for performance and system cost
benefits.

7
2.3. USE OF WASTE PLASTIC STRIPS MIXED WITH SOIL TO
INCREASE STRENGTH
Chandrakaran (2004)
It was explained using a laboratory experimental study carried out to utilize
waste plastics (in the form of strips) obtained from milk pouches in the pavement
construction. Results of the study indicate that by adding plastic strips in the soil,
shear strength, tensile strength and CBR values of the soil increases. In this study,
plastic or polythene sheets having thickness of 0.5mm and which are made up of
high density are used. These plastic strips have innumerable advantageous properties
like high tensile strength, low permeability etc., These plastic strips act as a good
barrier to gases and liquids and are unaffected by cycles of wetting and drying.
2.4. THE USE OF PVC SCRAP AS ALTERNATIVE BUILDING
MATERIALS
Agarwal (2004)
They have conducted pilot level studies using industrial PVC scrap to develop
PVC board. Efforts have been made in developing innovative number of such
alternative building materials. These would be helpful in saving our precious forest
and environment efficiently and economically on commercial exploitation.
Developed materials are mostly wood alternatives used in the construction of door
shutters, frames, false ceiling, thermal insulation and alike applications. Developed
sustainable alternative building materials are good economic replacement of wood
and other reconstituted wood products commercially available and would be helpful
in cost effective constructions.

8
2.5. USE OF PLASTIC WASTES IN ROAD CONSTRUCTION BY
PREVENTION OF DISPOSAL ON EARTH
Vasudevan (2004)
In his report, they have given the most useful ways of disposing waste plastics
and laying roads have come to light in a research carried out by the Chemistry
Department of Thiyagarajar College of Engineering. They have reported that the
waste plastics may be used in block making modified light roofing, mastic flooring
and polymer reinforced concrete. The novel composition of waste polymer-aggregate
blend has been patented. They have suggested that utilization of waste plastics to
enhance the binding property is better option than disposing or enforcing a blanket
ban on the use of plastics. It has been reported that the per capita use of plastics in
India is 3.5 kg, with virgin plastics accounting for 3.1 million tonnes and recycled
plastics, one million. The use in Tamil Nadu, with over 7000 units manufacturing
material is put at 2.4 lakh tonnes per year. The ‘Garbage Culture’ has made disposal
of waste plastic a major problem for civic bodies.

9
CHAPTER 3
METHODOLOGY
3.1 GENERAL
The following tests are being carried out well before the reinforcement is added to
properly determine the properties of soil. These tests are used to find out the various
characteristics of the soil. These tests help in determining properties such as size of
soil, specific gravity, cohesiveness, atterberg’s limit etc.
COLLECTION OF
MATERIALS
PRELIMINARY TEST
FOR SOIL
SHEAR AND
STRENGTH TEST
FOR SOIL
STRENGTH TESTS
WITH
REINFORCEMENTS
TEST RESULT AND
DISCUSSION
CONCLUSION

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3.2 TESTS CONDUCTED
The experimental work consists of the following steps:
1. Specific gravity of soil
2. Determination of soil index properties (Atterberg Limits)
i) Liquid limit by Casagrande’s apparatus
ii) Plastic limit
3. Particle size distribution by sieve analysis
4. Determination of the maximum dry density (MDD) and the corresponding
optimum moisture content (OMC) of the soil by Proctor compaction test
5. Preparation of reinforced soil samples.
6. Determination of the shear strength by:
i) Direct shear test (DST)
ii) Unconfined compression test (UCS).
iii) California Bearing Ratio test (CBR)

11
CHAPTER 4
EXPERIMENTAL INVESTIGATION
4.1 MATERIALS
 Soil sample
Location: In front of New Production Block, Velammal Engineering
College
 Reinforcement: Randomly oriented waste plastic fibers of random
dimensions
Fig 1: Preparation of Plastic Fibers from Waste Plastic

12
4.2 PREPARATION OF SAMPLES
Following steps are carried out while mixing the fiber to the soil,
 All the soil samples are compacted at their respective maximum dry
density (MDD) and optimum moisture content (OMC), corresponding to
the standard proctor compaction tests
 The different values adopted in the present study for the
percentage of fiber reinforcement are 0, 0.15, and 0.25.
 If fiber reinforcement was used, the adopted content of fibers was first
mixed into the air-dried soil in small increments by hand, making sure that
all the fibers were mixed thoroughly, so that a fairly homogenous mixture
is obtained, and then the required water was added.
4.3 BRIEF STEPS INVOLVED IN THE EXPERIMENTS
4.3.1 SIEVE ANALYSIS
Sieve analysis is the name given to the operation of dividing a sample of
aggregate into various fractions each consisting of particles of the same size.
The sieve analysis is conducted to determine the particle size distribution in a
sample of aggregate, which we call gradation.
The sieve analysis gives us a detailed idea regarding the type, consistency
and components of the soil.

13
4.3.2 Atterberg Limits
1) Shrinkage Limit:
This limit is achieved when further loss of water from the soil does not reduce
the volume of the soil. It can be more accurately defined as the lowest water
content at which the soil can still be completely saturated. It is denoted by wS.
2) Plastic Limit:
This limit lies between the plastic and semi-solid state of the soil. It is
determined by rolling out a thread of the soil on a flat surface which is non-
porous. It is the minimum water content at which the soil just begins to crumble
while rolling into a thread of approximately 3mm diameter. Plastic limit is
denoted by wP.
3) Liquid Limit:
It is the water content of the soil between the liquid state and plastic state of
the soil. It can be defined as the minimum water content at which the soil,
though in liquid state, shows small shearing strength against flowing. It is
measured by the Casagrande’s apparatus and is denoted by wL.
4.3.3 Particle Size Distribution
Soil at any place is composed of particles of a variety of sizes and
shapes, sizes ranging from a few microns to a few centimetres are present
sometimes in the same soil sample. The distribution of particles of different sizes
determines many physical properties of the soil such as its strength, permeability,
density etc. Particle size distribution is found out by two methods, first is sieve

14
analysis which is done for coarse grained soils only and the other method is
sedimentation analysis used for fine grained soil sample. Both are followed by
plotting the results on a semi-log graph. The percentage finer N as the ordinate and
the particle diameter i.e. sieve size as the abscissa on a logarithmic scale. The curve
generated from the result gives us an idea of the type and gradation of the soil. If
the curve is higher up or is more towards the left, it means that the soil has more
representation from the finer particles; if it is towards the right, we can deduce that
the soil has more of the coarse grained particles.
The soil may be of two types- well graded or poorly graded (uniformly
graded). Well graded soils have particles from all the size ranges in a good
amount. On the other hand, it is said to be poorly or uniformly graded if it has
particles of some sizes in excess and deficiency of particles of other sizes.
Sometimes the curve has a flat portion also which means there is an absence of
particles of intermediate size, these soils are also known as gap graded or skip
graded.
For analysis of the particle distribution, we sometimes use D10, D30, and
D60 etc. terms which represents a size in mm such that 10%, 30% and 60% of
particles respectively are finer than that size. The size of D10 also called the
effective size or diameter is a very useful data. There is a term called uniformity
coefficient Cu which comes from the ratio of D60 and D10, it gives a measure of the
range of the particle size of the soil sample.
4.3.4 Specific gravity
Specific gravity of a substance denotes the number of times that
substance is heavier than water. In simpler words we can define it as the ratio
between the mass of any substance of a definite volume divided by mass of equal

15
volume of water. In case of soils, specific gravity is the number of times the soil
solids are heavier than equal volume of water. Different types of soil have
different specific gravities, general range for specific gravity of soils:
Table 1: Specific Gravity Classification
1. Sand 2.63 - 2.67
2. Silt 2.65 - 2.7
3. Clay and Silty clay 2.67 - 2.9
4. Organic soil <2.0
4.3.5 SPECIFIC GRAVITY OF THE SOIL
The specific gravity of soil is the ratio between the weight of the soil solids
and weight of equal volume of water. It is measured by the help of a volumetric
flask in a very simple experimental setup where the volume of the soil is found
out and its weight is divided by the weight of equal volume of water.
Specific Gravity G =
w2-w1
[ w2-w1 - w3-w4 ]
Where,
W1- Weight of bottle (gms)
W2- Weight of bottle + Dry soil (gms)
W3- Weight of bottle + Soil + Water
W4- Weight of bottle + Water
Specific gravity is always measured in room temperature and reported to the nearest 0.1

16
4.3.6 LIQUID LIMIT
The Casagrande’s tool cuts a groove of size 2mm wide at the bottom and 11
mm wide at the top and 8 mm high. The number of blows used for the two soil
samples to come in contact is noted down. Graph is plotted taking number of
blows on a logarithmic scale on the abscissa and water content on the ordinate.
Liquid limit corresponds to 25 blows from the graph.
4.3.7 PLASTIC LIMIT
This is determined by rolling out soil till its diameter reaches approximately
3 mm and measuring water content for the soil which crumbles on reaching this
diameter.
Plasticity index (Ip) was also calculated with the help of liquid limit and
plastic limit;
Ip = wL – Wp
wL- Liquid limit wP- Plastic limit
Table 2: Classification of Soil according to Atterberg’s Limit
FIRST WORD SECOND WORD
SYMBOL DEFINITION SYMBOL DEFINITION
G GRAVEL P POORLY GRADED
S SAND W WELL GRADED
M SILT H HIGH PLASTICITY
C CLAY L LOW PLASTICITY
O ORGANIC

17
The results from sieve analysis of the soil when plotted on a semi-log graph
with particle diameter or the sieve size as the abscissa with logarithmic axis and the
percentage passing as the ordinate gives a clear idea about the particle size
distribution. From the help of this curve, D10 and D60 are determined. This D10 is
the diameter of the soil below which 10% of the soil particles lie. The ratio of,
D10 and D60 gives the uniformity coefficient (Cu) which in turn is a measure of the
particle size range.
4.3.9 PROCTOR COMPACTION TEST
This experiment gives a clear relationship between the dry density of the
soil and the moisture content of the soil. The experimental setup consists of (i)
cylindrical metal mould (internal diameter- 10.15 cm and internal height-11.7
cm), (ii) detachable base plate, (iii) collar (5 cm effective height), (iv) rammer (2.5
kg). Compaction process helps in increasing the bulk density by driving out the air
from the voids. The theory used in the experiment is that for any compactive effort,
the dry density depends upon the moisture content in the soil. The maximum dry
density (MDD) is achieved when the soil is compacted at relatively high moisture
content and almost all the air is driven out, this moisture content is called optimum
moisture content (OMC). After plotting the data from the experiment with water
content as the abscissa and dry density as the ordinate, we can obtain the OMC and
MDD. The equations used in this experiment are as follows:
Wet Density=
Weight of wet soil in mould (gms)
Volume of Mould (cc)

18
Moisture %=
Weight of water (gms)×100
Weight of dry soil (gms)
Dry Density ɣd
gm
cc
=
Wet density
1+Moisture Content
100
This test is used to find out the cohesion (c) and the angle of internal friction
(φ) of the soil, these are the soil shear strength parameters. The shear strength is one
of the most important soil properties and it is required whenever any structure
depends on the soil shearing resistance. The test is conducted by putting the soil at
OMC and MDD inside the shear box which is made up of two independent parts.
A constant normal load (ς) is applied to obtain one value of c and φ. Horizontal
load (shearing load) is increased at a constant rate and is applied till the failure point
is reached. This load when divided with the area gives the shear strength ‘τ’ for
that particular normal load. The equation goes as follows:
τ = c + σ*tan (φ)
After repeating the experiment for different normal loads (ς) we obtain a plot
which is a straight line with slope equal to angle of internal friction (φ) and intercept
equal to the cohesion (c). Direct shear test is the easiest and the quickest way to
determine the shear strength parameters of a soil sample.
This experiment is used to determine the unconfined compressive strength
of the soil sample which in turn is used to calculate the unconsolidated, undrained
shear strength of unconfined soil. The unconfined compressive strength (qu) is the
compressive stress at which the unconfined cylindrical soil sample fails under

19
simple compressive test. The experimental setup constitutes of the compression
device and dial gauges for load and deformation. The load was taken for different
readings of strain dial gauge starting from ε = 0.005 and increasing by 0.005 at
each step. The corrected cross-sectional area was calculated by dividing the area by
(1- ε) and then the compressive stress for each step was calculated by dividing the
load with the corrected area.
qu= load/corrected area (A’)
Where, qu - compressive stress
A’= cross-sectional area/ (1- ε)
4.3.12 CALIFORNIA BEARING RATIO TEST (CBR)
Bearing ratio is one of the vital parameters, used in the evaluation of soil sub
grades for both rigid and flexible pavements design. It is also an integral part of
several pavement thickness design methods. For this test cylindrical specimens were
prepared corresponding to their MDD at OMC in a rigid metallic cylinder mould
with an inside diameter of 150 mm and a height of 175 mm. A mechanical loading
machine equipped with a movable base that moves at a uniform rate of 1.2 mm/min
and a calibrated proving ring is used to record the load. For this, Static compaction is
done by keeping the mould assembly in compression machine and compacted the
soil by pressing the displacer disc till the level of the disc reaches the top of the
mould. Keep the load for some time, and then release.
CBR % =
{Load sustained by the specimen at 2.5 or 5.0mm penetration} x 100
Load sustained by standard aggregates at corresponding penetration level

20
CHAPTER 5
TEST RESULTS AND OBSERVATIONS
5.1 SPECIFIC GRAVITY
The specific gravity of the soil is determined using specific gravity test.
Table -3: Specific Gravity of the Soil Sample
Particulars Trial – 1 Trial – 2 Trial – 3
Wt. of Pyconometer (W1) 633 633 633
Wt. of Pyconometer+Soil (W2) 833 833 833
Wt. of Pyconometer+Soil+
Water (W3)
1700 1691 1701
Wt. of Pyconometer+Water
(W4)
1570 1572 1572
Average Specific Gravity of Soil = 2.81
Fig – 3: Pyconometer Apparatus in Specific Gravity Test

21
5.2 INDEX PROPERTIES
5.2.1 LIQUID LIMIT
The liquid limit is determined.
Table – 4: Liquid Limit of Soil Sample
No. of
Blows
Weight of
wet soil(gm)
Weight of
dry soil(gm)
Weight of
water(gm)
Moisture
Content(%)
56 14 11 3 27.27
19 16 13 3 23.07
10 17 13 4 30.76
• Liquid Limit (As obtained from the graph) = 27%
Fig – 4: No of Blows vs. Water Content Graph
59
19
10
0
10
20
30
40
50
60
70
27.27 23.07 30.76
No.ofBlows
Water Content (%)

22
Fig – 5: Liquid Limit using Casagrande Apparatus
Fig – 6: Plastic Limit on Glass Plate

23
5.2.2 PLASTIC LIMIT
• Weight of Container (W1) = 18g
• Weight of wet soil with container (W2) = 37g
• Weight of Dried soil with container (W3) = 34g
• Weight of water (W2-W3) = 3g
• Weight of dry soil (W2-W1) = 9g
5.2.3 PLASTICITY INDEX
• Plastic Limit (W) = {(w2-w3)/(w3-w1)} x 100
= 23%
• Plasticity Index (PI) = LL – PL
= 27 – 23 = 4%

24
Table – 5: Particle Size Distribution
IS
Sieve(mm)
Retained Weight
of Soil (gm)
% Retained Cumulative %
Retained (gm)
%
Finer
4.75 251 50.2 50.2 49.8
2.36 82 16.4 66.6 33.4
1.18 58 11.6 78.2 21.8
0.6 22 4.4 82.6 17.4
0.3 35 7.0 89.6 10.4
0.15 32 6.4 96.0 4.0
0.075 17 3.4 99.4 0.6
Pan 3 0.6 100 0
Fig – 7: Particle Distribution Graph
0
10
20
30
40
50
60
70
80
90
100
0.1 1 10
Percentagepassing(%)
Particle size, mm

25
So according to the gradation curve, we can say that the soil is of type GM – GW
(Gravel, Well – Graded with silt), as the percentage fine passing thru the #200 sieve
(0.075mm) is less than 5% (by IS code).
Fig – 8: Sieve Shaker Apparatus
5.2.5 MOISTURE CONTENT
Table – 6: Moisture Content of Sample
Wt. Of
Container (gm)
Wt. of container
+ Wet soil(gm)
Wt. of Container
+ Dry Soil (gm)
Moisture Content
(%)
19 57 52 15.15
18 69 63 12.33
18 54 49 16.12
Average Moisture Content = 14.86%

26
5.2.6 STANDARD PROCTOR COMPACTION
Table 7: Standard Procter Test Results
Weight of empty
mould(Wm) gms
2059 2059 2059
Internal diameter of mould
(d) cm
10 10 10
Height of mould (h) cm 12.5 12.5 12.5
Volume of mould (V) 981.75 981.75 981.75
Trial No. 1 2 3
Weight of Base plate (Wb) 2065 2065 2065
Weight of empty mould +
base plate
4124 4124 4124
Weight of mould +
compacted soil + Base plate
gms
6089 6179 6271
Weight of Compacted Soil
(W)gms
1965 2055 2149
Wet Density of Soil (W/V) 2.001 2.093 2.188
Moisture Content (w) 4% 6% 8%
Dry Density (wet/(1+w)) x
9.81
18.87 19.37 19.87
Optimum Moisture Content (OMC): 8%
Max. Dry Density (gm/cc) (MDD): 19.87 kN/m3

27
Fig – 9: Standard Procter Mould
5.2.7 DIRECT SHEAR
(i) Unreinforced Soil
Area of box: 36 cm2
Proving ring constant (k): 0.196
Table – 8: Direct Shear Test – Unreinforced Soil
Normal Stress
(kg/cm2
)
Proving Ring
Reading
Shear Load (Proving
Ring x k) kN
Shear Stress
(kN/cm2
)
0.5 54 10.584 0.294
1.0 84 16.464 0.457
1.5 106 20.776 0.577

28
Fig – 10: DST – Shear Stress Vs. Normal Stress Graph for unreinforced Soil
From Graph,
i) Cohesion(c): 0.16 kg/cm2
ii) Angle (φ): tan-1
(0.362) = 19.902
(ii) Reinforcement = 0.15%
Table – 9: Direct Shear Test – Reinforced Soil with 0.15% Plastic Fiber
Normal Stress
(kg/cm2
)
Proving Ring
Reading
Shear Load (Proving
Ring x k) kN
Shear Stress
(kN/cm2
)
0.5 78 15.288 0.424
1.0 121 23.716 0.658
1.5 164 32.144 0.892
0.294
0.457
0.577
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 0.5 1 1.5 2 2.5
ShearStress(kN/cm2)
Normal Stress (kg/cm2)

29
Fig – 11: DST – Shear Stress Vs. Normal Stress Graph for Reinforced Soil with
0.15% Plastic Fiber
From Graph,
Cohesion(c): 0.198 kg/cm2
Angle (φ): tan-1
(0.468) = 25.07
(iii) Reinforcement = 0.25%
Table 10: Direct Shear Test – Reinforced Soil with 0.25% Plastic Fibers
Normal Stress
(kg/cm2
)
Proving Ring
Reading
Shear Load (Proving
Ring x k) kN
Shear Stress
(kN/cm2
)
0.5 79 15.484 0.430
1.0 122 23.912 0.664
1.5 166 32.536 0.903
0.424
0.658
0.892
0
0.2
0.4
0.6
0.8
1
1.2
0 0.5 1 1.5 2 2.5
ShearStress(kN/cm2)
Normal Stress (kg/cm2 )

30
Fig – 12: DST – Shear Stress Vs Normal Stress Graph for reinforced with
0.25% Plastic Fibers
From Graph,
Cohesion(c): 0.199 kg/cm2
Angle (φ): tan (0.468) = 25.07
0.43
0.664
0.903
0
0.2
0.4
0.6
0.8
1
1.2
0 0.5 1 1.5 2 2.5
ShearStress(kg/cm2)
Normal Stress (kg/cm2 )

31
Fig 13: Direct Shear Sample Mould
Fig. 14: Direct Shear Apparatus

32
5.2.8 UNCONFINED COMPRESSION STRENGTH TEST
• Initial Length of sample: 6.9 cm
• Dia. Of sample: 3.7 cm
• Initial amount of soil taken: 3.5 kg
• Least count of dial gauge: 0.01 mm
• Proving ring constant: 4.14 N
• Initial cross sectional area of sample (A) : 3.14 x 1.852
= 1074 mm2
• Strain = Deformation/Original Length
• Corrected Area = A / (1 – Strain)
Fig – 15: Unconfined Compression Test Sample and Mould

33
i) Unreinforced Soil
Table – 11: Unconfined Compression Test – Unreinforced Soil
Dial gauge
reading
Strain(ϵ) Proving ring
reading
Corrected
area
load (N) Axial Stress
(Mpa)
50 0.0033 9 19.72 40.81 0.0207
100 0.0067 16 19.82 69.19 0.0349
150 0.0100 22 19.92 92.11 0.0462
200 0.0133 25 20.03 106.12 0.0530
250 0.0167 27 20.13 114.27 0.0567
300 0.0200 26 20.24 108.44 0.0536
350 0.0233 23 20.34 99.11 0.0487
0.0567
0
0.01
0.02
0.03
0.04
0.05
0.06
0 0.005 0.01 0.015 0.02 0.025
AxialStress(MPa)
Strain (ɛ)
Fig 16: UCS - Axial Stress vs. Strain Graph for
Unreinforced Soil

34
ii) Reinforcement = 0.15%
Table – 12: Unconfined Compression Test – Reinforced Soil with 0.15%
Plastic Fiber
Dial gauge
reading
reading
corrected
area
load (N) Axial Stress
(Mpa)
50 0.0033 13 19.72 54.8 0.0277
100 0.0067 20 19.82 82.79 0.0417
150 0.0100 26 19.92 109.6 0.0550
200 0.0133 29 20.03 122.43 0.0612
250 0.0167 31 20.13 128.26 0.0639
300 0.0200 29 20.24 120.1 0.0593
350 0.0233 26 20.34 107.27 0.0527

35
Fig 17: UCS - Axial Stress vs. Strain Graph for Reinforced Soil with 0.15%
Plastic Fiber
iii) Reinforcement = 0.25%
Table 13: Unconfined Compression Test – Reinforced Soil with 0.25%
Plastic Fiber
0.0639
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0 0.005 0.01 0.015 0.02 0.025
AxialStress(MPa)
Strain (ɛ)
Dial gauge
reading
reading
corrected
area
load (N) Axial Stress (Mpa)
50 0.0033 14 19.72 59.47 0.0302
100 0.0067 19 19.82 80.45 0.0406
150 0.0100 26 19.92 109.6 0.0550
200 0.0133 29 20.03 122.43 0.0612
250 0.0167 31 20.13 129.43 0.0643
300 0.0200 30 20.24 123.6 0.0611
350 0.0233 26 20.34 108.44 0.0533

36
Fig – 18: UCS - Axial Stress vs. Strain Graph for Reinforced Soil with
0.25% Plastic Fiber
0.0643
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0 0.005 0.01 0.015 0.02 0.025
AxialStress(MPa)
Strain (ɛ)

37
5.2.9 CALIFORNIA BEARING RATIO TEST (CBR)
1) Unsoaked Soil Sample
The CBR value is determined.
Table – 14: CBR Unsoaked Soil Sample
Penetration
(mm)
Load (kg) –
Unreinforced Soil
Load (kg) – 0.15%
Reinforced Soil
Load (kg) – 0.25%
Reinforced Soil
0.5 300 305 310
1.0 305 310 315
1.5 310 315 320
2.0 315 325 330
2.5 320 330 345
3.0 325 350 350
4.0 400 395 395
5.0 410 420 420
7.5 440 460 460
10.0 485 490 490
12.5 500 515 515
CBR Value: Unreinforced Soil = 23.537
0.15% Plastic reinforced = 24.087

38
Fig – 19: CBR – Unsoaked – Load Vs Penetration Graph Comparison
200
250
300
350
400
450
500
0 2 4 6 8
Load(kg)
Penetration (mm)
Unreinforced
Soil
0.15%
Reinforcement
0.25%
Reinforcement

39
2. Soaked Soil Sample
Table 15: CBR Unsoaked Test for Soil Sample
Penetration
(mm)
Load (kg) –
Unreinforced Soil
Load (kg) – 0.15%
Reinforced Soil
Load (kg) – 0.25%
Reinforced Soil
0.5 160 175 180
1.0 165 180 185
1.5 170 185 190
2.0 175 190 195
2.5 180 195 200
3.0 190 200 210
4.0 210 220 220
5.0 235 245 245
7.5 260 275 275
10.0 275 285 285
12.5 290 300 300
CBR Value: Unreinforced Soil = 13.138

40
Fig 20: Load Vs. Penetration Curve Comparison Graph for Soaked Soil
100
120
140
160
180
200
220
240
260
280
300
0 2 4 6 8
Load(kg)
Penetration (mm)
Unreinforce
d Soil
0.15%
Reinforceme
nt
0.25%
Reinforceme
nt

41
CHAPTER 6
CONCLUSIONS
The tests were conducted and the observed results were:
 The cohesion value of unreinforced soil is 0.16 kg/cm2 while for soil with
0.15% reinforcement is 0.198 kg/cm2 which is an increase of 19.19%
 The cohesion value of unreinforced soil is 0.16 kg/cm2 while for soil with
0.25% reinforcement is 0.199 kg/cm2 which is an increase of 19.50%
 The Unconfined Compression Strength of unreinforced soil is at a
maximum of 0.0567 MPa, the sample which is made based on IS codes.
 The Unconfined Compression Strength soil, reinforced with 0.15% of
waste plastic fibers is at a peak value of 0.0639 MPa which is an increase of
11.26% from 0.0567 MPa for unreinforced soil.
 The Unconfined Compression Strength soil, reinforced with 0.25% of
waste plastic fibers is at a peak value of 0.0643 MPa which is an increase of
12.10% from 0.0567 MPa for unreinforced soil.
 There is improvement in CBR value when waste plastic fibers are mixed
with the soil samples.
 The addition of reclaimed plastic waste material was to increase the CBR
value of the soil.

42
 The increase in CBR value with addition of plastic fibers would mean that
the thickness of the subgrade flexible pavement road would also be
reduced.

43
REFERENCES
[1] S. A. Naeini and S. M. Sadjadi ,(2008) ,” Effect of Waste Polymer Materials
on Shear Strength of Unsaturated Clays”, EJGE Journal, Vol 13, Bund k,(1-
12).
[2] Yetimoglu, T., Inanir, M., Inanir, O.E., (2005). A study on bearing capacity of
randomly distributed fiber-reinforced sand fills overlying soft clay. Geotextiles
and Geomembranes 23 (2), 174–183.
[3] Chaosheng Tang, Bin Shi, Wei Gao, Fengjun Chen, Yi Cai, (2006). Strength
and mechanical behavior of short polypropylene fiber reinforced and cement
stabilized clayey soil. Geotextiles and Geomembranes 25194–202.
[4] Mahmood R. Abdi, Ali Parsapajouh, and Mohammad A. Arjomand,(2008),”
Effects of Random Fiber Inclusion on Consolidation, Hydraulic Conductivity,
Swelling, Shrinkage Limit and Desiccation Cracking of Clays”, International
Journal of Civil Engineering, Vol. 6, No. 4, (284-292).
[5] Consoli, N. C., Prietto, P. D. M. and Ulbrich, L. A. (1999). ‘‘The behavior
of a fibre-reinforced cemented soil.’’ Ground Improvement, London, 3(1),
21–30.
[6] IS 2720 - 1980-87
[7] The need for soil stabilization, April 9, 2011 by Ana [online]
[8] Methods of soil stabilization, December 24, 2010 [online]
[9] Prof. Krishna Reddy, UIC, 2008, Engineering Properties of Soils
Based on Laboratory Testing.

44
[10] Understanding the Basics of Soil Stabilization: An Overview of Materials
and Techniques [online]
[11] Punmia B.C. 2007, “Soil Mechanics & Foundations” Laxmi Publications
[12] Yadav Parit, Meena Kuldeep Kumar, (2011)” A comparative study in soil
plasticity of Hall area and lecture complex area of NIT Rourkela” B.tech thesis,
NIT,Rourkela.
[ 1 3 ] IS: 2720(Part 2), 1973 Methods of Test for Soils, Determination
of water content.
[14] IS 2720(III/SEC-I): 1980 Methods of Test for Soils, Determination of
specific gravity.
[15] IS 2720(VII):1980 Methods of Test for Soils, Determination of
water content dry density relation using light compaction.
[16] IS 2720(XIII):1986 Methods of Test for Soils, direct shear test
[ 1 7 ] IS 2720(X):1991 Methods of Test for Soils, determination of
unconfined compression test.
[18] IS 2720(IV):1985 Methods of Test for Soils, determination of
grain size analysis.

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