2. 1
Table of Contents
Table of Figures....................................................................................................................................2
Table of Tables.....................................................................................................................................4
List of Symbols .....................................................................................................................................5
Table of Equation .................................................................................................................................6
Acknowledgement................................................................................................................................7
Abstract..................................................................................................................................................8
Chapter one ..........................................................................................................................................9
1.1 Introduction: .............................................................................................................................9
1.2 Aim ............................................................................................................................................10
1.3 Objectives: ..............................................................................................................................10
1.4 Description of chapters:......................................................................................................10
Chapter two.........................................................................................................................................12
2.1 Literature Review: .................................................................................................................12
2.2 Definitions .................................................................................................................................15
2.3 Advantages and Disadvantages of Shear Box test:...........................................................16
Loose and compacted Sand......................................................................................................17
2.4 Shear box test on rubber reinforced Sand:....................................................................17
2.5 Effect of mixing soil with other waste particles:...................................................................22
Chapter three......................................................................................................................................25
3.1 Research Methodology:.......................................................................................................25
3.2 Apparatus:.................................................................................................................................25
3.3 Procedure:...............................................................................................................................34
3.3.1 Stage 1...............................................................................................................................35
3.3.2 Stage 2...............................................................................................................................35
3.3.3 Note....................................................................................................................................36
Chapter Four.......................................................................................................................................36
4.1 Results: .....................................................................................................................................36
4.1.1 Uniform Distribution of Sand-Tyre Rubber in Riffle:........................................................36
4.2 Sieve Analysis:.......................................................................................................................38
4.3 Results of Experiment 1: ........................................................................................................40
4.4 Results of Experiment 2: ........................................................................................................43
4.5 Results of Experiment 3 .........................................................................................................46
4.6 Results of Experiment 4: ........................................................................................................50
Chapter six ..........................................................................................................................................57
5.1 Analysis:....................................................................................................................................57
3. 2
5.1.1 Calculation of Density of Sand:..........................................................................................57
5.2 Calculation of Experiment No. 1 (0% of tyre-rubber) .........................................................58
5.3 Calculation of Experiment No. 2 (5% of tyre-rubber):........................................................60
5.4 Calculation of Experiment No. 3 (10% of tyre-rubber).......................................................61
5.5 Calculation of Experiment No. 4 (15% of tyre-rubber).......................................................62
5.6 Calculation of Experiment No. 5 (20% of tyre-rubber).......................................................64
5.7 Note ...........................................................................................................................................65
5.8 Discussion: .............................................................................................................................65
Chapter 6.............................................................................................................................................69
6.1 Conclusion and Recommendation for future work ......................................................69
6.1.1 Conclusion...........................................................................................................................69
6.1.2 Recommendation for future work..................................................................................70
References:.........................................................................................................................................71
Appendix:.............................................................................................................................................73
Table of Figures
Figure 1 - Shear box apparatus devised by Collin in 1846....................................... 12
Figure 2 - Shear box designed by Bell in 1915......................................................... 13
Figure 3 - 60mm Shear box with displacement controls. Bishop (1946)................... 14
Figure 4 - how to work out the cohesion and friction angle when the graph is plotted
................................................................................................................................. 16
Figure 5 - Results of Zhao-hui Li and Hu-yuan Zhang (2010), Influence of rubber
content ..................................................................................................................... 20
Figure 6- Results of Gary J. Foose, Craig H. Benson and Peter J. Bosscher, (1996),
Influence of Shreds. ................................................................................................. 21
Figure 7– This graph shows Normal Stress and Shear Stress with various
percentage of mixtures. (Nima Latifi, Razieh Moradi, Mohsen Oghabi and Sayyed
Yaghoub Zolfeghari) (2013) ..................................................................................... 22
Figure 8- Sieve machine used to calculate the size of the sand particle .................. 25
Figure 9- Weighing scale: used for weighing material.............................................. 26
Figure 10- Stopwatch ............................................................................................... 26
Figure 11- Riffle used for uniform distribution of sand and rubber............................ 27
Figure 12- Shear Box: 60x60mm ............................................................................ 27
Figure 13- Pressure Pad with metal ball on it........................................................... 28
4. 3
Figure 14- Solid Rigid Plate...................................................................................... 28
Figure 15- The other side of the rigid plate............................................................... 29
Figure 16- Shear box Testing Machine .................................................................... 29
Figure 17- Hanger Load used to put weights to provide Normal Stress ................... 30
Figure 18- Proving ring............................................................................................. 31
Figure 19- Dial Gauge connected to proving ring: To record the readings when
shearing is in process............................................................................................... 31
Figure 20- Mechanical Lever: used for moving the shear carriage........................... 32
Figure 21- Displacement or speed control: used to set different speed rate for
shearing ................................................................................................................... 32
Figure 22- Shear box with 0% of tyre rubber............................................................ 33
Figure 23- Shear box mixed with Shredded tyre rubber........................................... 33
Figure 24 - Tyre rubber particles that were used to mix with sand .......................... 34
Figure 25– shows 70% mixture of sand and 30% mixture of gravel which makes the
soil a well graded gravelly sand. .............................................................................. 38
Figure 26– This Graph here shows the Plotted value of Normal stress and Shear
Stress. It shows a linear relationship, y = mx + c. This graph gives the values of
cohesion and Friction angle without any influence of Rubber content...................... 58
Figure 27– This Graph here shows the Plotted value of Normal stress and Shear
Stress. It shows a linear relationship, y = mx + c. From this graph, it can be clearly
seen that there is an increase in Shear stress and also Cohesion has increased.... 60
Figure 28 - This Graph here shows the Plotted value of Normal stress and Shear
Stress. It shows a linear relationship, y = mx + c. In this graph, the shear stress and
Cohesion has increased in comparison to 5% of rubber content ............................. 62
Figure 29- This Graph here shows the Plotted value of Normal stress and Shear
Stress. It shows a linear relationship, y = mx + c. In this graph the shear stress and
cohesion has decreased as compared to 10% of rubber but is still higher than 0% of
rubber content in sand.............................................................................................. 63
Figure 30- This Graph here shows the Plotted value of Normal stress and Shear
Stress. It shows a linear relationship, y = mx + c. In this graph the shear stress and
cohesion has decreased as compared to 15% of rubber ......................................... 64
Figure 31- shows the relation how the rubber content influenced the Cohesion. ..... 66
Figure 32– shows the relation how the rubber content influenced the angle of friction.
................................................................................................................................. 66
5. 4
Figure 33 Shows the best line of normal stress and shear stress points through each
other......................................................................................................................... 76
Table of Tables
4.2.1 Table 1 shows the analysis of Sieve containing sharp sand of mass 431.4g .. 38
4.3.1 Table 2 Shows the readings noted from dial gauge under 5kg with 0% of
rubber mixture .......................................................................................................... 40
4.3.2 Table 3 Shows the readings noted from dial gauge under 10kg with 0% of
rubber mixture .......................................................................................................... 41
4.3.3 Table 4 Shows the readings noted from dial gauge under 10kg with 0% of
rubber mixture .......................................................................................................... 42
4.4.1 Table 5 Shows the readings noted from dial gauge under 5kg with 5% of
rubber mixture .......................................................................................................... 43
4.4.2 Table 6 Shows the readings noted from dial gauge under 10kg with 5% of
rubber mixture .......................................................................................................... 44
4.4.3 Table 7 Shows the readings noted from dial gauge under 15kg with 5% of
rubber mixture .......................................................................................................... 45
4.5.1 Table 8 Shows the readings noted from dial gauge under 5kg with 10% of
rubber mixture .......................................................................................................... 46
4.5.2 Table 9 Shows the readings noted from dial gauge under 10kg with 10% of
rubber mixture .......................................................................................................... 47
4.5.3 Table 10 Shows the readings noted from dial gauge under 15kg with 10% of
rubber mixture .......................................................................................................... 49
4.6.1 Table 11 Shows the readings noted from dial gauge under 5kg with 15% of
rubber mixture .......................................................................................................... 50
4.6.2 Table 12 Shows the readings noted from dial gauge under 10kg with 15% of
rubber mixture .......................................................................................................... 51
4.6.3 Table 13 Shows the readings noted from dial gauge under 15kg with 15% of
rubber mixture 4.7 Results of Experiment 5: ............................................................ 52
4.7.1 Table 14 Shows the readings noted from dial gauge under 5kg with 20% of
rubber mixture .......................................................................................................... 53
4.7.2 Table 15 Shows the readings noted from dial gauge under 10kg with 20% of
rubber mixture .......................................................................................................... 55
6. 5
4.7.3 Table 16 Shows the readings noted from dial gauge under 15kg with 20% of
rubber mixture .......................................................................................................... 55
5.1.2 Table 17 Measurements of Depth of sand ...................................................... 57
5.2.1 Table 18 shows the computed peak shear by applying vertical load............... 58
5.2.2 Table 19 shows calculation of Normal stress and shear Stress ...................... 58
5.3.1 Table 20 shows the computed peak shear by applying vertical load Calculation
of Normal stress and Shear stress by using Equation 4 and 4................................. 60
5.3.2 Table 21 shows calculation of Normal stress and shear Stress ...................... 60
5.4.1 Table 22 shows the computed peak shear by applying vertical load............... 61
5.4.2 Table 23 shows calculation of Normal stress and shear Stress ...................... 61
5.5.1 Table 24 shows the computed peak shear by applying vertical load............... 62
5.5.2 Table 25 shows calculation of Normal stress and shear Stress ...................... 63
5.6.1 Table 26 shows the computed peak shear by applying vertical load............... 64
5.6.2 Table 27 shows calculation of Normal stress and shear Stress ...................... 64
5.8.1 Table 28 Shows the calculated value Cohesion and friction angle of various
rubber contents ........................................................................................................ 66
Table 29 Shows the reading noted from dial gauge on 5kg of load.......................... 73
Table 30 Shows the reading noted from dial gauge on 5kg of load.......................... 74
Table 31 Shows the reading noted from dial gauge on 5kg of load.......................... 75
Table 32 shows the computed peak shear by applying vertical load....................... 75
Table 33 shows calculation of Normal stress and shear Stress .............................. 76
List of Symbols
τ = Shear Stress
7. 6
C = Cohesion
σ = normal stress on shear plane
= Frictional Angle
Table of Equation
Percentage retained % = [𝑀𝑎𝑠𝑠 𝑟𝑒𝑡𝑎𝑖𝑛𝑒𝑑/𝑡𝑜𝑡𝑎𝑙 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑠𝑜𝑖𝑙]𝑥 100 Equation 1...... 39
Percentage passing % = 100 - percentage retained Equation 2 .............................. 39
Density of Sand =𝑀𝑎𝑠𝑠 𝑜𝑓 𝑆𝑎𝑛𝑑 − 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑆𝑎𝑛𝑑 Equation 3........................... 57
Normal Stress = 𝐹𝐴 = mxA = vertical Load x 9.81Area of Shear Box Equation 4 ....... 57
Shear stress = 𝐹𝐴 = mxA = Peak shear x 9.81/Area of Shear Box Equation 5 ....... 57
8. 7
Acknowledgement:
I would like to take this opportunity to thank Dr. John Walsh for always
showing a positive approach towards me and helping me whenever I was in
doubt about my research. I am also thankful to the university engineering
department and Mr. Trevor for guiding me during the lab experiments. He has
provided me with all the materials and I very much appreciate his contribution.
Words cannot describe how thankful I am to my supervisor Dr. Alireza
Ahangar-Asr for giving me an opportunity to work on this project. He has been
a great supervisor by helping me profoundly in my research, clearing my
doubts and giving me proper guidance.
Also, I would like to thank my father Mr. Mushtaq Malik for being a disciplined
mentor and my best friend. Without him I would have never accomplished any
goals in my life. ‘Dad, you have provided me the best things in life and I hope
one day I will make you proud’.
9. 8
Abstract:
This project is simply based on the investigation of shear strength of rubber-reinforced
sand. Direct shear tests were carried out on sharp sand by mixing it with 5%, 10%,
15% and 20% of tyre rubber. Each test was carried twice or thrice to get the better
results. After the data was analysed, the results clearly showed that there was
increase in shear strength with increase in rubber content. The cohesion of sharp sand
alone was 4.3Kpa which increased to 7.5 and 12.5 after mixing 5% and 10% of rubber
content. After 10% of mixture the cohesion started decreasing with increase in rubber
content in sand. Similarly, angle of friction decreased with increase in rubber content.
The friction angle of sand alone was 21.8degrees which decreased to 19.65 degrees
and 15.25 degrees after mixing 5% and 10% of rubber. The research clearly illustrates
that the maximum shear strength was recorded in 10% of tyre rubber-sharp sand
mixture. Thus influencing the properties of sharp sand. This type of sand is used in
construction field such as in macadam and concrete mixture where this waste material
can be used. Sufficient amount of information and investigation needs to be carried
out before applying this laboratory result in practical field
Keywords: Shear Strength Properties, Shear Stress, Normal Stress, Cohesion,
Angle of friction, Sharp Sand, tyre Rubber.
.
10. 9
Chapter one
1.1 Introduction:
In order to create a sustainable future we have to use and recycle every waste material
that is polluting the environment. There are many waste material that cannot be
decomposed after the material has been used. In this research I will be focusing on
tyre rubber and how it can be utilized in construction field.
According to the survey of US environmental agency there are around 2-3 billion waste
tyres and the growth rate of these tyre rubber is 200-300 million per year. This waste
material can be seen in every corner of the world.
In industrialized nations, rubber tires alone record for 60% of the total rubber
consumption. The rest of the 40% of rubber consumption is from belt and shoe industry
and so on. An average weight of a tyre rubber is 5KN/ m3. In past years the waste
tyres were buried but due to their bulky and large shape land ability to migrate through
soil surface it has been banned. Countries like Germany and UK the growth rate of
waste tyre rubber is 0.6 million and 0.74 million per year respectively.
According to the new US and EU legislation to ensure the environmentally safe
disposal of waste rubber, there has been a huge growth in tyre recycling industry.
These recycling industries have shown a massive growth in technical solution for the
recycling of waste rubber. Legislations differ from country to country but main problem
is to use these huge stock piles and provide the safety of the environment.
The main problem of the waste tyre rubber is the fire hazard. Once a large stock pile
of tyre catches fire, it is very difficult to control it. Due to this, diseases such as
encephalitis and dengue fever has been reported from many several areas where
these waste tyres catch fire. In recent times, the tyre rubber has been replaced by the
widespread use of synthetic rubber and steel belted radial rubber. This has been the
most important cause for non-recycling of tyre rubber.
Currently in the UK waste rubber particles is available in sizes no greater than 5mm
and is produced in either 'chipped' or 'shredded' forms. These waste particles can be
also be used in construction industry such as in a form of rubber-sand mixture.
Various experiments had been carried out to check the possibility of mixing rubber
with sand to find out how much percentage of rubber can be mixed with sand for the
11. 10
construction purposes. Shear box test is one of the experiment, which can be used to
find out the shear strength of sand. According to Roy Whitlow (2012) Shear box test
is a direct shear test because both the normal stress and shear stress acts directly on
the failure surface. The shear box is filled with soil which is split in two halves.
According to the British standard the size of the shear box is 60mm x 60mm but for
testing different materials such as coarse soils and fissured clay a larger size of shear
box can be used. The specimen can be assessed under various loads and the results
are compared. The direct shear test can be used to determine the parameters of the
soil. The procedure of shearing is repeated twice or thrice on different load and
shearing force is measured by a dial gauge connected to the proving ring. The data is
then analysed to calculate normal stress and shear stress of each test. These two
values are plotted against each and fitted by a straight line through the plotted points.
Various types of sand can be investigated in shear box test.
Sand is mostly used for construction and mixture of sand-rubber can be very beneficial
in practical field. Shear box test can be used to check the parameters of this mixture
and state whether the rubber has influenced the sand in a positive manner. Many geo-
synthetic material has been added to the soil for construction purposes and results
has been very positive. As many experiments had been carried out in past years to
find out the shear strength of sand-rubber mixture by using shear box test, the same
procedure will be followed.
1.2 Aim: The aim of this project is to investigate the shear strength of Rubber
reinforced Sand
1.3 Objectives:
1. To add 5%, 10%, 15%, 20% of tyre rubber with sharp sand
2. Study the effect and influence of tyre rubber on the properties of sharp Sand
1.4 Description of chapters:
Chapter one – Introduction: This chapter includes about the information on
rubber as a waste material and how it can be used in construction industry for
a sustainable future. Also, the main aim of this research and objectives which
needs to be accomplished
Chapter two – Literature review: This chapter includes the history of the shear
box, how it was designed and what are the changes that have been made in
12. 11
the past years. Also, it includes the researches other people have done on the
same subject and how it can be compared to the result of this project. Effect of
mixing soil with other waste particles.
Chapter 3 – Research Methodology: Apparatus used in the experiments. The
procedure which was followed to complete all the experiments and how the
data was recorded.
Chapter 4 – Results: The data obtained from the experiments.
Chapter 5 – Analysis and Discussion: The data obtained from the experiments
were analysed in this section and graphs were plotted. It also included the
discussion which part which comments on the analysis data and compares it
with the research of other people
Chapter 6 - Conclusion and recommendations for Future work: This section
includes the conclusion that explains the output of the results and what this
project has achieved. Recommendation for further work explain what other
thing could have been done or can be done to improvise the subject.
13. 12
Chapter two
2.1 Literature Review:
According to Lambe & Whitman, 1969 direct shear box test is a simple test used for
testing soil. Coulomb performed the first shear box test in 1776. Later, a French
Engineer Alexandre Collin distinctly featured shear box test in 1846 (Skempton, 1984).
Alexandre Collin used a split box, which was 350mm in long. For testing he used a
clay sample 40 x 40mm in section, which was subjected to double shear by applying
load of hanging weights.
Figure 1 - Shear box apparatus devised by Collin in 1846
Section a: General arrangements.
Section b: Forces on sheared portion of sample
14. 13
In Britain 1915, Bell designed a device, which was an ideal model of shear box test
with further developments. According to Skempton 1958, Bell was the first person to
carry out shear box test on different types of soil material and publish the results.
Then in 1932, a simple shear box was designed with a single shear of plane by using
a shear control principle where the load was applied by adding weights to a pan. For
this type of shear box test, it required a great concentration and judgement by the
operator to decide at which load the shear strength failure occurred.
Figure 2 - Shear box designed by Bell in 1915
Many people from stage to stage Massachusetts Institute of Technology completed
the developments in shear box. In 1932 at Harvard (USA) A. Casagrande designed a
shear box following after 4 years Gilboy at Massachusetts Institute of Technology
developed a machine by applying a strain control principle using a fixed speed motor
with a constant rate of displacement. Then in 1946, Bishop at imperial college
improved the design using the shear box principle in many details. Shear box
machines are still focused on displacement controls, which give an extensive variety
displacement speed ranging from a couple of millimetres per minute to around 10000
times slower.
15. 14
Figure 3 - 60mm Shear box with displacement controls. Bishop (1946)
The general concept or principle of shear box test is very simple and the procedure is
very straightforward. A sample of soil is place in a square metal box consisting of two
halves. A motorised machine installed in the shear box apparatus pushes or pulls the
lower part, which slides proportionately to the upper half while the load hanger
supported by a yoke provided the normal pressure by adding weights.
Now the concept of shear box test is cleared and the justification shows that the shear
box test is used to measure the shear strength. As in my previous discussion, my
research is about the mixing of rubber with sand and how we can use it in construction
purpose.
Coulomb’s law of soil shear strength:
According to G N Smith (Elements of Soil Mechanics) Coulomb in 1773 governed the
parameters of shear strength of soil by a straight-line equation in Coulomb’s law of
shear strength:
τ = σ tan (ø) + c Equation 1
Where
τ = Shear Stress
C = Cohesion
σ = normal stress on shear plane
16. 15
ø = Frictional Angle
2.2 Definitions
Shear Force: A force which acts perpendicular to a plane of section
Stress: Strength or Intensity of Force
Strain: Change in length per unit length due to a stress measures in the direction of
stress
Shear Stress: Shear force per unit normal area
Shear Strength: Maximum shearing resistance or strength of soil when put under load
condition in shear box test.
Displacement: When the one halve of the shear box slides relatively or
proportionately to other halve
Angle of Friction: Component of shear strength of soil which is due to friction between
the particles
Cohesion: Shear strength of soil when subjected to normal stress or confining
pressure
Failure: When the constant or continued shear strength starts decreasing or falling
down.
17. 16
Figure 4 - how to work out the cohesion and friction angle when the graph is plotted
This figure gives us a basic idea of how to work out the cohesion and friction angle
when the graph is plotted
2.3 Advantages and Disadvantages of Shear Box test:
Advantages:
According to Roy Whitlow (Basic Soil Mechanics
1. The shear stress and the normal stress on the plane of failure are measured
directly.
2. Change in volume can be measured easily
3. Constant or continuous normal stress can be maintained throughout the test
4. Basic principle of shear box test is very simple
5. The test is very easy to carry out
6. Angle of friction between many engineering materials can be measured.
7. The shear box test can be reversed for the measurement of residual shear
strength
8. The shear box test can be used for drained test
Normal stress
Shear Stress
τ
C
Ø
18. 17
Disadvantages:
1. During the test it is assumed that the distribution of shear stress over the plane
of failure is uniform, but actually it’s not.
2. Pore water pressure cannot be measured directly.
3. It’s impossible to control the drainage, except by changing the rate of shear
displacement.
Loose and compacted Sand: According to Roy Whitlow (2012), grains in dense
sands are very interlocked. In order for the shearing to occur, an early expansion of
the grains is very important. So that the shear stress will rise abruptly with increase in
volume until it reaches a value where it starts falling down. The interlocking of the
grains keeps reducing the displacements starts increasing where shears stress falls
down until it reaches to an ultimate peal value or shear failure. While in loose sand,
grain particles are not closely packed. A small displacement can increase the change
in volume. Such materials are easily compacted under high load. The ultimate peak
value of the soil depends upon its state, where the dense soil will dilate and the loose
soil will contract.
2.4 Shear box test on rubber reinforced Sand:
According to the research of P.K. Woodward on shear strength of rubber reinforced
sand for use as a lightweight fill material Shear box test were carried out on a series
of rubber reinforced sand to determine how the percentage rubber content in the
composite influenced the shear strength. This publication has been greatly refined as
it provides a lot of data, which can be used during the experiment. The sand used in
this study was 'Levenseat' sand which is a naturally occurring fine grained granular
material. Two different types of discarded tyres were used; 'granulated' rubber and
'shredded' rubber. The different percentages of rubber tested were 0%, 10%, 20% and
40%, which is a good idea of carrying out different experiments. The shear box test on
zero percent mixture of rubber with sand will give the shear strength properties of
19. 18
sand, which can further be compared when the other percentage of rubber will be
mixed. It can give us a brief data on the change in properties of sand. One of the
important point written in the publication is It was observed that as the amount of
rubber in the composite increased the amount of segregation of the particles also
increased this was particularly noticeable in the shredded composite. The maximum
dry density achieved during this test decreased with the increasing number of rubber
percentage. Two different densities were chosen during the experiment namely loose
and medium dense. According to P.K. Woodward, the friction angle for the smaller
rubber chips and shredded rubber gives a linear relationship between medium and
loose dense state, also cohesion seems to increase with increase in rubber particles.
The friction angle of levenseat sand in loosest state and medium state was 21 degrees
and 31 degrees respectively. Similarly in rubber chip samples, the friction angle was
19 degrees and 18 degrees in its loosest state and medium state respectively. While
the friction angle of Pure shredded rubber was slightly higher than the rubber chip
samples which was 22 degrees in both states. In the loosest state of levenseat sand,
both the rubber chips and shred rubber improved the shear strength of sand till the
15% of mixture. After 15% of mixture the increasing rubber percentage started to
influence or reduce the shear strength properties of sand. While in medium dense
state the friction angle was limited to 10% of rubber mixture. The maximum shear
strength obtained was 5 degrees by mixing 10% of rubber shreds in loose state and
1.5 degrees using 10% of rubber chips in the medium dense state. Thus, according
to this paper the mixing of small amount of rubber particles with sand do have a
positive impact on the shear strength properties by concluding that the improvement
to shear strength properties of levenseat sand was found to be in between 10% and
20%.
In this research, the author has quoted that the large percentage of rubber contents in
soil leads to the reduction of shear strength, which is not feasible for the construction
industry or any type of field where we can use this waste material. The test in this
paper was carried out in two different states loose and medium dense. Firstly when
the test was carried out without any mixture the angle of friction was higher but when
the rubber content was added the angle of friction started decreasing as the influence
of increasing rubber percentage started changing the properties of soil. So this paper
clearly classifies that the decrease in angle of friction with the increase in rubber
20. 19
content during the tests should be expected. As decided in this project there are many
experiments to be carried out with different rubber percentage, percentage level
should be relevant to the paper results but not similar. Also, the paper clearly justifies
the fact that improvement in shear strength was found to be in 10% and 20%.
The zero percent rubber mixture in sand will give output results of shear strength,
cohesion and angle of friction. On adding different percentage of rubber 5%, 10%,
15% and 20% under different loadings of 5KG, 10KG and 15KG, the change in shear
strength of sand and to what percentage the shear strength improves can easily be
examined. In this paper the author has mentioned using two types of rubber for the
experiment.
According to the report of Zhao-hui and Li Hu-yuan Zhang (2010), the granulated
rubber was mixed with loess mixture to perform the shear box test. The granulated
rubber mixture with loess mixture was of 0%, 10%, 20%, 30%, 40%, 50%, 100%. Four
types of normal stresses: 100kPa, 150kPa, 200kPa, 250kPa were applied under a
speed rate of 0.8mm/min. The result output of this shear box test was that shear
strength of rubber mixture increases abruptly when the rubber particles are added till
20% and then starts decreasing when the rubber percentage is increased to 30%.
Similarly Cohesion increases with increases in rubber percentage till 20% and angle
of friction decreases respectively. This type of rubber can be used to increase the
shear strength properties of sand, which is very useful for highway embankment.
The report of Zhao-hui Hu-yuan Zhang is quite relevant or comparable to the report of
PK Woodward. As the material used in both test was different there are some
differences in the report. In both publications, the addition of large rubber contents
results in the reduction of shear strength in soil. The shear strength in both reports
improves in 10-30% of rubber content. These two reports has provided a lot of data in
which can be used during the experiment that on what percentage the shear strength
will decrease.
21. 20
Figure 5 - Results of Zhao-hui Li and Hu-yuan Zhang (2010), Influence of rubber
content
According to the investigation performed by three members of American Society of
Civil Engineers (Gary J. Foose, Craig H. Benson and Peter J. Bosscher, 1996), the
shear strength of Sand reinforced Shredded waste tires was calculated through a
series of direct shear test. Three important elements, which affect the shear strength,
are Normal stress, Sand Matrix Unit weight and Shred-tire content. In all cases, the
shear strength of Sand reinforced tire was greater than the shear strength of sand.
The sand used for the experiment was Portage sand and the initial friction angle of
sand was 34° which increased to 67° after the shredded tire content was added to the
sand mixture. The sand Matrix unit weight is one of the basic parameter affecting the
initial friction angle. It’s clearly illustrated in the report that the sand reinforced shred-
tire having Sand Matrix unit weight = 16.8 KN/m3 has 15° higher friction angle than
the mixture having matrix unit weight of 14.7 or 15.7 KN/m3. The friction angle of
portage sand was 9° which means that the shear strength of the sand was influenced
22. 21
by the Shredded tire material. Thus the report concludes that reinforcing the sand with
shred tire content can increase the shear strength properties of portage sand.
Figure 6- Results of Gary J. Foose, Craig H. Benson and Peter J. Bosscher, (1996),
Influence of Shreds.
In 2013, four PhD students from University technology of Malaysia (2013) (Nima Latifi,
Razieh Moradi, Mohsen Oghabi and Sayyed Yaghoub Zolfeghari) carried out various
Direct shear test on river sand reinforcing with tire chips. The basic idea of this
research was study that how tire chips affect the shear strength properties of sand.
For this purpose, 10%, 20%, 30%, 40% and 50% of tire chips were mixed with the total
weight of sand. Also, after increasing the tire chips content to 20% the internal friction
angle also increases from 32.8° to 34.2°. Initially the friction angle of sand alone was
17° which mean that the tire chips has improved the shear strength properties of sand.
The shear strength properties increases till the optimum percentage amount of 20%
but when the tire chip content is increased after 20% the shear strength starts
decreasing especially when the test is carried out in higher normal stress.
23. 22
Figure 7– This graph shows Normal Stress and Shear Stress with various percentage
of mixtures. (Nima Latifi, Razieh Moradi, Mohsen Oghabi and Sayyed Yaghoub
Zolfeghari) (2013)
2.5 Effect of mixing soil with other waste particles:
There are many methods of increasing the shear strength of sand such as
Mixing of Sand with fibre particles: According to Babu & Vasudevan,2008, fibre
particle is the most inexpensive material which is easily available and environment
friendly. Reinforcing fibre with soil not only increases the shear strength but also the
cohesion between the particles. One of the main reasons of mixing fibre with soil is
that it acts as soil structural element to keep the soil particles close together. There
are many types of fibre particles for example Date Palm Fibre, Coconut Fibre and
Polypropylene fibre, which can be mixed with sand to improve the properties and the
mechanical procedure is minimal.
According to the research done by Islam, Mohammad S. and Kazuyoshi Iwashita
(2009) of mixing date palm fibre on a silty sand soil, the result clearly indicated that
the soil grains are replaced by the fibre particles and controls the soil structure.
California Bearing ratio was used to perform this experiment on 12 different wet
samples. Fibre length chosen for this experiment were 20mm and 40mm and mixing
percentage of fibre in soil was 0.25%, 0.50%, 0.75%, 1.00% and 1.50%. After the
experiment was finished the result clearly indicated that at a penetration of 13mm the
shear strength of silty soil without fibre is 6000kpa and after mixing soil with highest
24. 23
percentage of 1.5% fibre the shear strength increases to 16000KPa which means
26.7% of increase in shear strength of fibre reinforced soil.
Steel wire reinforcement: This is the most commonly used method in construction
industry. This is the procedure of dividing compacted soil in layers and then reinforcing
each layer with steel wire mesh. According to Pereira (Toxic Effects Caused by
Stainless Steel Corrosion Products on Mouse Seminiferous Cells 1994) the most
important advantage of using this soil is that material used in this procedure is very
light and easy to construct. The machinery used for this type of construction is backhoe
and compactor. This disadvantage of this method is that this type of procedure cannot
be used in soil with higher contents of silt and clay. Furthermore, at the end life of steel
it is not very useful because corroded steel is very harmful for the environment.
Geo-synthetics Material: This is the same method of dividing each compacted soil
in layers and then reinforcing it with geo-synthetic material. The geo synthetic
reinforcement is used in two ways during slope reinforcement. The first step is to place
narrow strips at the end of slope, which prevents sloughing, and erosion. The second
step is to fill in geo synthetic materials perpendicular to normal stress plane. According
to Brown (Building with Reinforced Soil 2006) and Holtz (Geosynthetics for Soil
Reinforcement 2001) the advantages of this method is that it allows good filtration and
drainage and its manmade properties gives synthetic material a very long life span
which has been calculated between 500 to 5000 years. Limitation of this method is
that this procedure can be bit expensive and it cannot be applied in high slope areas,
which is a problem for poor communities.
Mixing lime to the soil: This is the method of mixing lime with soil to increase the
load bearing capacity of the soil. This type of method is mostly done my mixing lime
with clay of moderate to high plasticity due to its increase in strength of properties. The
calcium present in the hydrated lime replaces the cation present in the clay mineral.
The advantage of this method is that it can be easily implemented and disadvantage
is that its stability has a very short life. Also it’s very harmful for plants and animals
(The National Lime Association, 2003).
Effect of mixing soil with materials: According to all these researches, its cleared
that’s these materials do have a effect on the properties of soil and the shear strength
can be increased by adding various materials to the soil. Rubber, Fibre, Geo-synthetic
25. 24
and lime can be used to mix with soil to influence the soil properties. As my project is
based on Sand reinforced rubber it’s clearly illustrated in the above articles that the
rubber can be a good element for use in various construction purposes. By adding
different percentage of rubber in sand, I will get various results of direct shear test and
explain that how much percentage of rubber can be added to increase the shear
strength properties of soil and at what percentage it might start decreasing.
26. 25
Chapter three
3.1 Research Methodology:
In this part of the section, I will discuss the method or procedure, which was used
during the shear box test
3.2 Apparatus:
Figure 8- Sieve machine used to calculate the size of the sand particle
28. 27
Figure 11- Riffle used for uniform distribution of sand and rubber
Figure 12- Shear Box: 60x60mm
Swan-neck loading
yoke
29. 28
Figure 13- Pressure Pad with metal ball on it
Figure 14- Solid Rigid Plate
Metal Ball
30. 29
Figure 15- The other side of the rigid plate
Figure 16- Shear box Testing Machine
31. 30
Figure 17- Hanger Load used to put weights to provide Normal Stress
Weight on Hanger Load
32. 31
Figure 18- Proving ring
Figure 19- Dial Gauge connected to proving ring: To record the readings when
shearing is in process.
Proving Ring
Dial Gauge
33. 32
Figure 20- Mechanical Lever: used for moving the shear carriage.
Figure 21- Displacement or speed control: used to set different speed rate for
shearing
Lever
34. 33
Figure 22- Shear box with 0% of tyre rubber
Figure 23- Shear box mixed with Shredded tyre rubber
35. 34
Figure 24 - Tyre rubber particles that were used to mix with sand
3.3 Procedure:
Initial Readings
Before the start of experiment, the dimensions (width, height and the depth) of
the shear box were measured by using a vernier calliper and noted down.
The length and breadth of the plates, which are placed on the top and beneath
the layer of the soil, were measured by using vernier calliper.
The weight of the shear box with plates including a ball on its top was measured
by using a weighing scale.
The sand was then filled into the shear box and again the weight was measured.
From this the mass of the soil was calculated.
Sieve analysis was performed to calculate the size distribution of Sharp sand. The test
took approximately twenty minutes and the experiment was carried out under the
guidance of lab technician. The sieve analysis was performed according to the British
standard and results were recorded and then analysed to plot the graph.
General Statement of the procedure applied in the laboratory for all experiments:
After all the readings were noted down the experiment was started under the
supervision of the lab technician. The first direct shear test on sand was done without
adding any percentage of rubber.
36. 35
Firstly the lower retaining plate and lower perforated solid grid was placed in
the shear box.
Then the shear was filled with the sand and the upper perforated solid grid plate
was put on the top layer of the soil just below the pressure ball.
The shear box was placed in the carriage of the testing machine.
The load hanger was placed on the top of the bearing ball on pressure pad and
5kg of load was put on the hanger for the first experiment.
The mechanical handle or lever was rotated carefully until the load transfer arm
of the shear box touched the proving ring. Then the dial gauge was set to zero.
The two screws fitted inside the shear box were removed.
The speed rate of the shear-testing machine was set to .3048mm/min.
The switch of the motor was turned on to start shearing.
Readings were noted down from the proving dial gauge at a regular interval of
15 second.
The experiment was stopped after the needle of dial gauge stopped moving
and the final reading was taken.
The experiment was performed on three test load 5kg, 10kg, 15kg plus the
weight of hanger
3.3.1 Stage 1:
This procedure was followed in all the experiment performed in the laboratory. As
previously said, the first experiment was performed without mixing any tyre rubber
content in sharp sand on 5kg of load plus the load of hanger to provide normal stress.
This experiment was repeated again on 5kg to check the previous results. After
completing all the experiment on 5kg, another load of 10 kg was put on the hanger.
Same procedure was repeated again and the experiment was done twice to check the
results. Subsequently 15kg of load was put on the hanger and was performed twice to
check the results.
3.3.2 Stage 2:
The rubber was mixed in sharp sand after all the experiments on sand alone was
completed. To mix rubber with sand, riffle was used for the uniform distribution of sand
37. 36
and rubber. 5% of rubber was mixed with sand and filled in shear box. Same procedure
was applied under three different loading of 5kg, 10kg, and 15kg to provide normal
stress. Each experiment was repeated twice or thrice to check the results. Similarly
10%, 15%, 20% of rubber was added in sand by using riffle to create a uniform mixture
and many experiments were performed. These experiments were completed in
different stages and were examined according to the results. The data, which was
being recorded in every experiment, gave an indication that each experiment is
showing different results, thus the properties of sand are changing after each
experiment.
3.3.3 Note: The soil filled in the shear box was not compacted. The state of the soil in
shear box was loose.
Chapter Four
4.1 Results:
1. Measurements were taken by using a vernier calliper
2. Solid Rigid Plate = 59.47mm x 59.33mm
3. Shear box = 59.73mm x 59.83mm
4. Depth of Shear Box = 44.44mm
5. Weight of each material was weighed by using a weighing scale
6. Weight of pressure including the metal ball = 376.7g
7. Weight of solid rigid plate = 58g
8. Weight of shear box = 3010.3g
9. Weight of shear box filled with sand = 3201.5g
10.Therefore, mass of sand in box = 3201.5 – 3010.3 = 191.3g
11. Weight of Hanger = 4169.7g
4.1.1 Uniform Distribution of Sand-Tyre Rubber in Riffle:
For 5%, 10g of rubber and 190g of sand were taken which is 5% of rubber and
95% of sand, 200g in total.
For 10%, 30g of rubber and 270g of sand were taken which is 10% of rubber
and 90% of sand, 300g in total.
38. 37
For 15%, 45g of rubber and 255g of sand were taken, which is 15% of rubber
and 85% of sand, 300g in total.
For 20%, 80g of rubber and 320g of sand were taken, which is 20% of rubber
and 80% of sand, 400g in total.
Important point: The mass of sand or rubber-sand mixture in shear box was kept
constant i.e. 191.3g in every experiment
39. 38
4.2 Sieve Analysis:
Mass of sharp sand = 431.4g
Number of sieves used = 9
Time Taken: 20 minutes
4.2.1 Table 1 shows the analysis of Sieve containing sharp sand of mass 431.4g
Sieve Size Mass retained Percentage retained % Percentage passing %
4.75mm 2.8 0.65 99.35
1.18mm 126.5 29.33 70.02
600µm 100.5 23.3 46.72
425µm 61.7 14.3 32.42
300µm 64.6 14.98 17.44
250µm 19.5 4.52 12.32
212µm 11.8 2.73 10.19
150µm 26.1 6.05 4.14
63µm 15 3.47 .67
Residue 2.7g 0.626 0.04
Total mass 431.2
Figure 25– shows 70% mixture of sand and 30% mixture of gravel which makes the
soil a well graded gravelly sand.
0
20
40
60
80
100
120
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Percentagepassing
British standard sieve sizes mm
GravelSand
40. 39
431.4 grams of sharp sand was used in sieve shaker to investigate the particle size.
Sieve shaker machine took approximately 20 minutes to finish the whole test. The
material in each pan was weighed which is called mass retained. The raw data was
then noted for further analysis.
Percentage retained % =
𝑀𝑎𝑠𝑠 𝑟𝑒𝑡𝑎𝑖𝑛𝑒𝑑
𝑡𝑜𝑡𝑎𝑙 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑠𝑜𝑖𝑙
𝑥 100 Equation 1
Percentage passing % = 100 - percentage retained Equation 2
The percentage passing was calculated for each sieve sizes which was plotted on a
graph. In figure 25, it clearly shows that 70% of mixture is sand and 30% of mixture
is gravel. Thus, the material is gravelly-sand. There was no percentage of silt in soil.
57. 56
The results in these table shows the reading taken from dial guage after interval of
each 15 seconds. Each results were assessed twice or thrice to check if there’s any
error. In some experiments, the dial gauge needle was showing abrupt reaction by
moving in clockwise direction while in other experiments it took a bit time to move.
This may be a cause of error in following the procedures properly. Each table in the
result section has different values and the last shear reading was noted when the
needle stopped moving or for 45 second to 60 seconds when the dial gauge was
giving the same reading. The tables clearly shows that with increase in rubber
percentage and load the shear reading was increasing. The rubber material has
influenced the sand in a very positive impact.
58. 57
Chapter six
5.1 Analysis:
Area of Shear box = 59.73mm x 59.83mm = 3.573𝑚2
x10−3
5.1.1 Calculation of Density of Sand:
Depth of
Box
44.44mm 44.29mm 44.31mm 44.35mm Average =
44.34mm
Depth of
box with
sand
6.2mm 6.8mm 6.4mm 6.6mm Average =
6.5mm
5.1.2 Table 17 Measurements of Depth of sand
Therefore, depth of Sand = Average depth of box – Average depth of box with Sand
= 44.34mm - 6.5mm = 37.84mm = 0.03784m
Volume of Sand = Area of the sample sand x depth of Sand
3.573𝑚2
x10−3
x 0.03784m = 1.35226x10−4
𝑚3
Density of Sand =
𝑀𝑎𝑠𝑠 𝑜𝑓 𝑆𝑎𝑛𝑑
𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑆𝑎𝑛𝑑
Equation 3
.1913𝑘𝑔
1.35226𝑥10−4 𝑚3 = 1414.69kg/𝑚3
Vertical Load = Weight of Hanger + Weight on Hanger + Grid Plate + Pressure Pad
Peak Shear = Shear failure x 0.03KGF
Normal Stress =
𝐹
𝐴
=
𝑚𝑥𝑎
𝐴
=
𝑣𝑒𝑟𝑡𝑖𝑐𝑎𝑙 𝐿𝑜𝑎𝑑 𝑥 9.81
𝐴𝑟𝑒𝑎 𝑜𝑓 𝑆ℎ𝑒𝑎𝑟 𝐵𝑜𝑥
Equation 4
Shear stress =
𝐹
𝐴
=
𝑚𝑥𝑎
𝐴
=
𝑃𝑒𝑎𝑘 𝑠ℎ𝑒𝑎𝑟 𝑥 9.81
𝐴𝑟𝑒𝑎 𝑜𝑓 𝑆ℎ𝑒𝑎𝑟 𝐵𝑜𝑥
Equation 5
59. 58
5.2 Calculation of Experiment No. 1 (0% of tyre-rubber)
Vertical Load Kg Peak Shear Kgf
9.604 7.18
14.604 10.32
19.604 13.35
5.2.1 Table 18 shows the computed peak shear by applying vertical load
Calculation of Normal stress and Shear stress by using Equation 4 and 5
Vertical Load
Kg
Peak Shear Kgf Normal Stress
Kpa
Shear Stress
Kpa
9.604 7.18 26.36 19.71
14.604 10.32 40.096 28.33
19.604 13.35 53.82 36.65
5.2.2 Table 19 shows calculation of Normal stress and shear Stress
Figure 26– This Graph here shows the Plotted value of Normal stress and Shear
Stress. It shows a linear relationship, y = mx + c. This graph gives the values of
cohesion and Friction angle without any influence of Rubber content.
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60
Shearstresskpa
Normal Stress Kpa
60. 59
Cohesion = 4.3Kpa
Angle of friction was calculated by constructing a right angle tri-angle on the graph
Tan = P/B
Tan =
1.8
4.5
, = 21.80
Angle of Friction = 21.80
61. 60
5.3 Calculation of Experiment No. 2 (5% of tyre-rubber):
Vertical Load Kg Peak Shear Kgf
9.604 8.21
14.604 10.94
19.604 13.61
5.3.1 Table 20 shows the computed peak shear by applying vertical load
Calculation of Normal stress and Shear stress by using Equation 4 and 4
Vertical Load
Kg
Peak Shear Kgf Normal Stress
Kpa
Shear Stress
Kpa
9.604 8.21 26.36 22.52
14.604 10.94 40.096 30
19.604 13.61 53.82 37.3
5.3.2 Table 21 shows calculation of Normal stress and shear Stress
Figure 27– This Graph here shows the Plotted value of Normal stress and Shear
Stress. It shows a linear relationship, y = mx + c. From this graph, it can be clearly
seen that there is an increase in Shear stress and also Cohesion has increased.
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60
ShearstressKpa
Normal Stress
62. 61
Cohesion = 7.5Kpa
Angle of friction was calculated by constructing a right angle tri-angle on the graph
Tan = P/B
Tan =
1.5
4.2
, = 19.650
Angle of Friction = 19.650
5.4 Calculation of Experiment No. 3 (10% of tyre-rubber)
Vertical Load Kg Peak Shear Kgf
9.604 9.925
14.604 12.96
19.604 15.78
5.4.1 Table 22 shows the computed peak shear by applying vertical load
Calculation of Normal stress and Shear stress by using Equation 4 and 5
Vertical Load
Kg
Peak Shear Kgf Normal Stress
Kpa
Shear Stress
Kpa
9.604 9.925 26.36 27.25
14.604 12.96 40.096 35.582
19.604 15.78 53.82 43.325
5.4.2 Table 23 shows calculation of Normal stress and shear Stress
63. 62
Figure 28 - This Graph here shows the Plotted value of Normal stress and Shear
Stress. It shows a linear relationship, y = mx + c. In this graph, the shear stress and
Cohesion has increased in comparison to 5% of rubber content.
Cohesion = 12.5Kpa
Angle of friction was calculated by constructing a right angle tri-angle on the graph
Tan = P/B
Tan =
1.2
4.4
= 15.250
Angle of Friction = 15.250
5.5 Calculation of Experiment No. 4 (15% of tyre-rubber)
Vertical Load Kg Peak Shear Kgf
9.604 7.32
14.604 9.99
19.604 12.54
5.5.1 Table 24 shows the computed peak shear by applying vertical load
0
5
10
15
20
25
30
35
40
45
50
0 10 20 30 40 50 60
ShearstressKpa
Normal stress Kpa
64. 63
Calculation of Normal stress and Shear stress by using Equation 4 and 5
Vertical Load
Kg
Peak Shear Kgf Normal Stress
Kpa
Shear Stress
Kpa
9.604 7.32 26.36 21.33
14.604 9.99 40.096 27.42
19.604 12.54 53.82 34.42
5.5.2 Table 25 shows calculation of Normal stress and shear Stress
Figure 29- This Graph here shows the Plotted value of Normal stress and Shear
Stress. It shows a linear relationship, y = mx + c. In this graph the shear stress and
cohesion has decreased as compared to 10% of rubber but is still higher than 0% of
rubber content in sand.
Cohesion = 6.5Kpa
Angle of friction was calculated by constructing a right angle tri-angle on the graph
Tan = P/B
Tan =
0.9
3.1
= 16.180
Angle of Friction = 16.180
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60
ShearStressKpa
Normal stress Kpa
65. 64
5.6 Calculation of Experiment No. 5 (20% of tyre-rubber)
Vertical Load Kg Peak Shear Kgf
9.604 7.05
14.604 9.69
19.604 12.56
5.6.1 Table 26 shows the computed peak shear by applying vertical load
Calculation of Normal stress and Shear stress by using Equation 4 and 5
Vertical Load
Kg
Peak Shear Kgf Normal Stress
Kpa
Shear Stress
Kpa
9.604 7.05 26.36 19.356
14.604 9.69 40.096 26.604
19.604 13.14 53.82 34.5
5.6.2 Table 27 shows calculation of Normal stress and shear Stress
Figure 30- This Graph here shows the Plotted value of Normal stress and Shear
Stress. It shows a linear relationship, y = mx + c. In this graph the shear stress and
cohesion has decreased as compared to 15% of rubber
Cohesion = 4.96Kpa
Angle of friction was calculated by constructing a right angle tri-angle on the graph
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60
ShearstressKpa
Normal Stress kpa
66. 65
Tan = P/B
Tan =
0.98
3.1
= 17.540
Angle of Friction = 17.540
5.7 Note: All these angles were also measured by protractor scale and there wasn’t
much difference but just to get the right value in decimal places right angle triangle
was constructed on each graph.
5.8 Discussion:
The main aim of this project was to influence or increase the properties of sand, which
according to the analysis has been achieved. The analysis clearly shows that there
was increase in shear strength when the sand was reinforced with tyre rubber.
Although there was a decrease in shear strength properties of sand mixed with rubber
but it was comparatively higher than the Shear strength of sand alone.
In the first set of experiment, direct test were carried out on sand alone and then the
data was analysed to calculate friction angle and Cohesion, which was 4.3kpa
and 21.80
respectively. After mixing 5% of tyre rubber in sand, the analysis of the data
output resulted in increase of cohesion and decrease in angle of friction i.e. 7.5kpa
and 19.650
respectively.
Rubber Content Cohesion Kpa Friction Angle
0% 4.3 21.8
5% 7.5 19.65
10% 12.5 15.25
15% 6.5 16.18
20% 4.96 17.54
67. 66
5.8.1 Table 28 Shows the calculated value Cohesion and friction angle of various
rubber contents
Figure 31- shows the relation how the rubber content influenced the Cohesion.
Figure 32– shows the relation how the rubber content influenced the angle of friction.
From Graph 31, it shows that cohesion increases with increase in rubber percentage.
In between 5% to 10% the cohesion is higher as compared to 15% and 20% which
0
2
4
6
8
10
12
14
0% 5% 10% 15% 20%
Cohesion
Rubber Content
0
5
10
15
20
25
0% 5% 10% 15% 20%
AngleofFriction
Rubber Content
68. 67
means 5% and 10% improves the shear strength properties more as compared to
other percentage of rubber content. 10% of rubber content shows much increase in
cohesion and after that with increase in rubber percentage the cohesion starts
decreasing. Similarly, In Graph 32, it shows with increase in rubber percentage the
angle of friction starts decreasing. The minimum angle of friction was recorded in 10%
of rubber in which the cohesion was higher. With increase in rubber percentage the
angle of friction starts increasing after 10% of rubber content but still lesser than 0%
of rubber content. Thus, the tyre rubber improves the shear strength properties of
sand.
According to the research of P.K. Woodward (2012) the maximum shear strength
achieved was in 10% of rubber shreds and 10% of rubber chips which if compared to
the data analysed in this project is same as 10% of tyre shows the higher shear
strength value. The shear strength improves from 10% to 20% while in this case the
shear strength improves from 5% to 10%. This can be a reason using different material
of sand and rubber or the state of sand in research. P.K. Woodward has described
using loosest and dense medium of levenseat sand while in this case the state of sand
was loose. In both researches the shear strength decreases with increase in rubber
percentage after a certain percentage of rubber content.
According to the second research of Zhao-hui discussed in literature review, the shear
strength increases in loess-granular rubber mixture and starts decreasing after 20%.
If compared to results obtained in this project, the sharp sand- tyre rubber mixture
shows the same change, while the only difference is that maximum shear strength is
achieved from 5% to 10% as said above. In both cases, the shear strength of sand-
rubber mixture increases and then starts reducing.
While in some other cases, with increase in rubber percentage the angle of friction has
increased. The other two reports of Gary J. Foose, Craig H. Benson and Peter J.
Bosscher, (1996) and Nima Latifi, Razieh Moradi, Mohsen Oghabi and Sayyed
Yaghoub Zolfeghari (2013) has stated that the internal angle of friction has increased
with increase in rubber content. This has influenced the shear strength properties of
sand. In comparison to the data analysed in this project, angle of friction has reduced
in every test with increase in rubber content. Thus, these two reports in comparison to
our project have shown a reverse effect.
69. 68
During the start of the project, it was predicted that the tyre rubber will influence the
properties of sand and there will be an increase in shear strength. Also, on some stage
the shear strength will start reducing and there will be a range of X% to Y% where the
rubber has influenced the sand more. In the above-analysed data these prediction to
some extent has been achieved.
The reduction of friction angle has increased because the rubber has very less density
than the sharp sand, which means with increase in tyre rubber content in sharp sand
it started changing the structural properties of sand. This influenced the shear strength
properties and at certain percentage it started falling down.
There were many problems faced during the experiments. The computer software,
which was connected to the shear-testing machine wasn’t working or not giving the
proper output of the graph. Also, the dial gauge connected to the proving ring was not
giving accurate results so the dial gauge was changed. Furthermore, each experiment
was performed twice or thrice to get the best result. In many tests, the result was
matching and there wasn’t much difference in peak shear failure but in some cases
the peak shear failure was different and thus the experiment was done again. These
errors may have occurred by not following the procedures correctly or lack of
concentration during the experiments.
The sharp sand is used for construction purposes like macadam or mixing with
concrete. So waste tyre rubber can be used in sharp sand to increase the shear
strength properties but before using this waste rubber as a catalyst for sharp sand this
mixture of sand– rubber has to be applied in the construction field. So an experiment
should be done on these two materials to investigate the shear strength properties
and then mixed with the concrete or macadam to see whether it’s sustainable to use
for the construction. For example, according to P.K. Woodward (1998), the mixture of
levenseat sand and granulated rubber can be used as a light weight fill material and
Zhao-hui Li and Hu-yuan Zhang. (july 24th, 2010), the mixture of loess sand and
granulated rubber can be used for highway embankments. Thus, the tyre rubber has
influenced the shear strength properties of sharp sand with very positive impacts and
can this mixture can be used for the purposes of macadam and concrete purposes.
These laboratory results do provide useful result but if this mixture has to be used in
70. 69
construction field the data is not sufficient for the engineer. More investigation needs
to be done on this mixture so the results are applicable for construction use.
Chapter 6
6.1 Conclusion and Recommendation for future work:
6.1.1 Conclusion:
The main aim of this project was simply to investigate the shear strength of
rubber-sand mixture, which has been achieved.
Adding 5%, 10%, 15%, and 20% of tyre rubber in sharp sand completed the
objectives.
The rubber influenced the shear strength of sand and thus it increased with
increase in rubber percentage.
Cohesion increased and friction angle decreased with increase in rubber
percentage.
After 10% of rubber content, Cohesion decreases and angle of friction
increases.
At 10% of rubber content, shear strength is much higher as compared to other
results as cohesion is maximum and angle of friction is minimum as compared
to other results
All the mixture of rubber content with sand increased the shear strength
properties of sand as compared to the sand alone.
The mixture of tyre rubber and Sharp sand can be used in construction industry
but sufficient work has to be done so that it can be applied in practical use.
71. 70
6.1.2 Recommendation for future work:
To add more percentage of rubber content so that the influence of higher rubber
percentage can be assessed.
To do the shear box test on both loose and compacted sand.
To add different types of rubber materials with various types of Sand.
To repeat the experiments many times so that better results can be analysed.
To read many articles on rubber-sand mixture and other waste materials.
To study the parameters of shear box test.
To use a shear testing machine which is connected to the computer to compute
values.
72. 71
References:
1. Ahmed, R. and Van de Klundert, A, (1994).Rubber recycling. 20th WEDC
conference, Colombo, Sri Lanka,
2. Asmirza, M.S., . (1996). Direct Shear Testing.
3. Black, B.A. and Shakoor, A., (1994). 'A Geotechnical investigation of soil-tyre
mixtures for engineering applications, First international congress on
environmental geotechnics,
4. Boscher, P.J., Edil, T.B. and Eldin, N.N, (1992). Construction and performance
of a shredded waste tire test embankment. Transportation Research Board,
Washington DC, Transportation Research Board No 1345, 44-52,
5. BS(1990), BS 1377-7: 1990, Methods of test for soils for civil engineering
purposes- part7: Shear strength test (total stress), 1 (7), p2-32
6. Edil, T.B. and Bosscher, P.J., (1994) Engineering properties of tire chips and
soil mixtures. Geotechnical Testing Journal, Vol 17, No 4, 453-464,
7. Eldin, N.N., and Senouci. (1993) 'Rubber-tire particles as concrete aggregate.
Journal of Materials in Civil Engineering, Vol. 5, No. 4, 478-496.
8. Foose,G.J., Benson, C.H., and Bosscher. P.J., (1996). Sand Reinforced with
Shredded Waste tires. Journal of Geotechnical Engineering.122 (9). 760-767.
9. Gaw, B., Zamora, S.(2011) Soil Reinforcement with Natural Fibers for Low-
Income Housing Communities
10.Head, K.H and Epps, R.J.(2011). Manual of Soil Laboratory Testing 3rd edition.
Caithness: Whittles Publishing. 208-262
11.Head, k.h. and Epps, r.j. (2014) manual of soil laboratory testing. 3rd edition:
whittles publishing. Volume iii.
12.Hsing wu, T. (1971) Soil dynamics. Second edition. Atlantic avenue, boston:
allyn and bacon inc
13.Humphrey, D.N. and Manion, W.P., (1992). Properties of tire chips for
lightweight fill. Grouting, soil improvement and geosynthetics, American Society
of Civil Engineers, New York, Geotechnical special publication, No 30, Vol. 2,
1344-1355.
14.L. E. Vallejo, Y. Zhou, “The mechanical properties of simulated soil rock
mixtures,” C //Porc. of the 13th Intern. Conf. on Soil Mech. And Found. Eng.
,New Delhi, India, Vol. 1, January 10, 1994: 365-368.
15.Latifi, N., Moradi, R., Oghabi, M. and Zolfeghari, S.Y., (2013). Shear Properties
of Sand, 325-334
16.Li. Zhao-hui and Zhang. Hu-yuan, (2010).Shear strength of Granulated rubber
and Loess mixture as lightweight, Geomaterials.
17.Poulin, F. (1996) 'Large shear box testing on rubber/sand composites, Heriot-
Watt University.
18.Poulin, F., (1996). Large shear box testing on rubber/sand composites, MSc
dissertation, Heriot-Watt University,
19.Powrie, W. (2004). Soil mechanics concepts & applications. 2nd ed. Abingdon,
oxon: spon press. 76-80.
20.Scrap tyre recycling, available at
http://www.waste-management-world.com/articles/2003/07/scrap-tyre-
recycling.html [Accessed on 2nd September 2014]
21.Smith G.N. (1982). Elements of soil mechanics. 5th ed. Great britain: richard
clay (the chaucer press) ltd. 128-135.
22.Smith. M.J., 1984. Soil Mechanics, 4th Ed. George Godwin. ELBS.
73. 72
23.Whitlow, r. (1995). Basic soil mechanics. 3rd ed. United states : john wliey &
sons. 212-224.
24.William, T. and Lambe., 1951. Soils Testing for engineers. The Massachusets
Institute of Technology, John wiley & Sons. Inc. New York
25.Woodward, P.K. (1998) 'Observations on the direct shear strength of a sand-
rubber mixture for use as a lightweight fill material'
Bibliography:
1. Das, B. M. 1994. Principles of Geotechnical Engineering, 3rd Edition. PWS.
Publishing compaqny, Boston.
2. Fredlund, D.G., and Rahardjo, H., 1993. Soil Mechacnis fort Unsaturated soils,
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Applied Science Pub., London.
74. 73
Appendix:
Shear box test was performed on two different masses of sand. 175.3g and 191.3g.
The mass of the sharp sand filled in shear box which was analysed is 191.3g. This
amount of soil was kept constant in all the experiments.
Shear Box test on 175.3g
Experiment 1
0% of Rubber
Load on Hanger = 5kg
Time
interval
Dial gauge
Readings
Time
interval
Dial gauge
Readings
15 4 390 203
30 18 405 206
45 30 420 210
60 41 435 214
75 45 450 217
90 51 465 221
105 62 480 225
120 73 495 230
135 82 510 233
150 89 525 238
165 96 540 243
180 105 555 246
195 115 570 248
210 123 585 252
225 130 600 256
240 137 615 258
255 146 630 259
270 154
285 160
300 167
315 175
330 181
345 188
360 194
375 199
Table 29. Shows the reading noted from dial gauge on 5kg of load
77. 76
Calculation of Normal stress and Shear stress by using Equation 4 and 5
Vertical Load
Kg
Peak Shear Kgf Normal Stress
Kpa
Shear Stress
Kpa
9.604 7.77 26.36 21.29
14.604 11.53 40.096 31.65
19.604 14.79 53.82 40.524
Table 33. shows calculation of Normal stress and shear Stress
Figure 33. Shows the best line of normal stress and shear stress points through each
other.
Cohesion = 4.8
Angle of Friction = tan = P/B
tan =
1
2.1
= 25.460
This shear box test was performed on 175.3g of sharp sand. If these results are
compared to results of 191.3g of sharp sand alone, there is a slight difference in
cohesion and angle of friction.
0
5
10
15
20
25
30
35
40
45
0 10 20 30 40 50 60
ShearStressKpa
Normal Stress Kpa
