Dissertation FD11

2014

Adil Mushtaq – u1151709

Supervisor-Dr Alireza Ahangar-asr

12/12/2014

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


4.5 Results of Experiment 3 ......................................................................................................... 46


Chapter six .......................................................................................................................................... 57

5.1 Analysis: .................................................................................................................................... 57

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



5.7 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

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


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



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

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


rubber mixture .......................................................................................................... 41


rubber mixture .......................................................................................................... 42


rubber mixture .......................................................................................................... 43


rubber mixture .......................................................................................................... 44


rubber mixture .......................................................................................................... 45


rubber mixture .......................................................................................................... 46


rubber mixture .......................................................................................................... 47


rubber mixture .......................................................................................................... 49


rubber mixture .......................................................................................................... 50


rubber mixture .......................................................................................................... 51


rubber mixture 4.7 Results of Experiment 5: ............................................................ 52


rubber mixture .......................................................................................................... 53


rubber mixture .......................................................................................................... 55

5


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








5.8.1 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 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

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

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’.

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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.

.

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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

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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

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.

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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

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.

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

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.

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

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

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

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.

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

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.

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

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

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.

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

26

Figure 9- Weighing scale: used for weighing material

Figure 10- Stopwatch

27

Figure 11- Riffle used for uniform distribution of sand and rubber

Figure 12- Shear Box: 60x60mm

Swan-neck loading

yoke

28

Figure 13- Pressure Pad with metal ball on it

Figure 14- Solid Rigid Plate

Metal Ball

29

Figure 15- The other side of the rigid plate

Figure 16- Shear box Testing Machine

30

Figure 17- Hanger Load used to put weights to provide Normal Stress

Weight on Hanger Load

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

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

33

Figure 22- Shear box with 0% of tyre rubber

Figure 23- Shear box mixed with Shredded tyre rubber

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.

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

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.

37

For 15%, 45g of rubber and 255g of sand were taken, which is 15% of rubber


For 20%, 80g of rubber and 320g of sand were taken, which is 20% of rubber


Important point: The mass of sand or rubber-sand mixture in shear box was kept

constant i.e. 191.3g in every experiment

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

Pe

rcen

tage

pa

ssin

g

British standard sieve sizes mm

GravelSand

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 𝑠𝑜𝑖𝑙𝑥 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.

40

4.3 Results of Experiment 1:

Rubber Content = 0%

Load on Hanger = 5kg

Time Interval in

second Dial gauge reading

Time Interval in

second

Dial gauge

reading

15 5 375 200

30 30 390 202

45 50 405 204

60 69 420 207

75 85 435 209

90 95 450 212

105 105 465 213

120 115 480 216

135 125 495 217

150 135 510 220

165 143 525 222

180 147 540 224

195 152 555 226

210 159 570 228

225 163 585 231

240 173 600 232

255 176 615 235

270 184 630 237

285 185 645 238

300 190 660 239

315 193 675 239

330 193

345 195

360 198


rubber mixture

41

Rubber Content = 0%


Time Interval in


Time Interval in

second

Dial gauge

reading

15 10 375 310

30 40 390 311

45 70 405 314

60 95 420 322

75 110 435 324

90 130 450 332

105 147 465 333

120 157 480 338

135 173 495 340

150 185 510 342

165 203 525 342

180 210 540 344

195 220 555 344

210 230

225 236

240 244

255 250

270 258

285 265

300 275

315 280

330 290

345 301

360 305


rubber mixture

42

Rubber Content = 0%


Time Interval in


Time Interval in

second

Dial gauge

reading

15 10 375 417

30 45 390 423

45 85 405 436

60 105 420 438

75 135 435 440

90 156 450 443

105 177 465 444

120 195 480 444

135 210 495 445

150 220 510 445

165 245

180 257

195 272

210 287

225 310

240 325

255 336

270 349

285 365

300 372

315 385

330 392

345 396

360 411


rubber mixture

43


Rubber Content = 5%


Time Interval in


Time Interval in

second

Dial gauge

reading

15 8 360 198

30 36 375 204

45 54 390 210

60 65 405 215

75 77 420 219

90 85 435 224

105 98 450 227

120 108 465 233

135 117 480 239

150 129 495 243

165 135 510 246

180 141 525 250

195 147 540 254

210 152 555 259

225 156 570 262

240 161 585 264

255 165 600 267

270 169 615 268

285 171 630 269

300 175 645 270

315 182 660 272

330 187 675 273

345 191 690 273


rubber mixture

44

Rubber Content = 5%


Time Interval in

seconds Dial gauge reading

Time Interval in

seconds

Dial gauge

reading

15 8 375 326

30 28 390 330

45 45 405 333

60 68 420 335

75 88 435 337

90 108 450 339

105 125 465 342

120 142 480 346

135 153 495 350

150 169 510 352

165 189 525 355

180 204 540 357

195 212 555 360

210 222 570 363

225 232 585 364

240 245 600 364

255 256

270 262

285 269

300 278

315 290

330 299

345 307

360 317


rubber mixture

45

Rubber Content = 5%


Time Interval in seconds Dial gauge reading

Time Interval in

seconds

Dial gauge

reading

15 15 360 393

30 45 375 399

45 68 390 404

60 88 405 406

75 109 420 412

90 129 435 417

105 148 450 421

120 164 465 424

135 188 480 428

150 208 495 431

165 235 510 433

180 259 525 436

195 275 540 440

210 288 555 442

225 297 570 448

240 309 585 451

255 321 600 453

270 336 615 453

285 351

300 368

315 379

330 385

345 390


rubber mixture

46


Rubber content = 10%


Time Interval in

seconds

Dial gauge

reading

Time Interval in

seconds Dial gauge reading

15 11 375 205

30 29 390 214

45 43 405 226

60 53 420 233

75 61 435 241

90 71 450 250

105 81 465 257

120 88 480 258

135 96 495 262

150 103 510 268

165 110 525 275

180 116 540 281

195 123 555 287

210 128 570 292

225 137 585 298

240 146 600 304

255 153 615 308

270 159 630 311

285 165 645 316

300 171 660 318

315 178 675 321

330 185 690 326

345 191 705 327

360 199 720 330


rubber mixture

47



Time Interval in

seconds

Dial gauge

reading

Time Interval in

seconds

Dial gauge

reading

15 19 375 361

30 40 390 373

45 58 405 378

60 72 420 381

75 86 435 384

90 96 450 390

105 210 465 394

120 220 480 398

135 229 495 402

150 238 510 405

165 247 525 412

180 259 540 414

195 268 555 418

210 275 570 420

225 284 585 423

240 293 600 428

255 304 615 430

270 309 630 432

285 315 645 432

300 323 660 432

315 330 675 432

330 338

345 346

360 353


rubber mixture

48



Time Interval in

seconds

Dial gauge

reading

Time Interval in

seconds

Dial gauge

reading

15 28 390 338

30 55 405 348

45 71 420 360

60 90 435 366

75 114 450 376

90 120 465 388

105 133 480 398

120 146 495 406

135 161 510 413

150 173 525 429

165 186 540 436

180 197 570 451

195 209 585 453

210 214 600 461

225 221 615 468

240 231 630 475

255 241 645 480

270 252 660 486

285 263 675 492

300 275 690 497

315 292 705 500

330 293 720 509

345 306 735 511

360 315 750 514

375 323 765 517

49

Time Interval in

seconds

Dial gauge

reading

780 522

795 523

810 526

825 526

840 526


rubber mixture

50


Rubber Content = 15%


Time Interval in

seconds

Dial gauge

reading

Time Interval in

seconds

Dial gauge

reading

15 5 375 219

30 25 390 225

45 39 405 227

60 45 420 231

75 58 435 233

90 70 450 235

105 78 465 236

120 89 480 238

135 97 495 237

150 105 510 240

165 115 525 242

180 125 540 243

195 133 555 244

210 142 570 244

225 148

240 156

255 262

270 168

285 175

300 184

315 195

330 205

345 210

360 215


rubber mixture

51


Load on Hanger = 10Kg

Time Interval in

seconds

Dial gauge

reading

Time Interval in

seconds

Dial gauge

reading

15 3 390 196

30 25 405 202

45 39 420 214

60 49 435 222

75 58 450 231

90 63 465 239

105 71 480 246

120 77 495 253

135 84 510 259

150 88 525 266

165 95 540 271

180 105 555 278

195 112 570 285

210 118 585 293

225 125 600 301

240 132 615 305

255 139 630 311

270 145 645 313

285 153 660 316

300 159 675 319

315 164 690 321

330 170 705 324

345 176 720 326

360 182 735 329

375 189 750 333


rubber mixture

52


Load on Hanger = 15Kg

Time Interval in

seconds

Dial gauge

reading

Time Interval in

seconds

Dial gauge

reading

15 24 390 311

30 49 405 319

45 66 420 325

60 78 435 333

75 89 450 345

90 101 465 351

105 112 480 359

120 123 495 365

135 131 510 371

150 143 525 378

165 152 540 382

180 166 555 385

195 173 570 391

210 188 585 395

225 201 600 399

240 215 615 402

255 226 630 404

270 239 645 407

285 247 660 411

300 258 675 412

315 268 690 414

330 277 705 415

345 285 720 416

360 294 735 417

375 303 750 418


rubber mixture

53




Time Interval in

seconds

Readings on Dial

Gauge

Time Interval in

seconds

Dial gauge

reading

15 15 360 163

30 27 375 167

45 35 390 172

60 45 405 175

75 51 420 179

90 59 435 185

105 65 450 187

120 73 465 191

135 80 480 195

150 85 495 199

165 91 510 206

180 97 525 207

195 103 540 210

210 108 565 215

225 112 580 216

240 119 595 221

255 125 600 223

270 132 615 225

285 136 630 228

300 143 645 231

315 145 660 232

330 155 675 234

345 159 690 235


rubber mixture

54



Time Interval in

seconds

Readings on Dial

Gauge

Time Interval in

seconds

Dial gauge

reading

15 3 390 192

30 25 420 229

45 39 435 232

60 49 450 236

75 58 465 240

90 63 480 243

105 71 495 254

120 77 510 259

135 84 525 261

150 88 540 263

165 95 565 267

180 105 580 271

195 112 595 274

210 118 600 280

225 123 615 285

240 130 630 287

255 135 645 289

270 141 660 293

285 150 675 305

300 157 690 307

315 158 705 311

330 162 720 314

345 173 735 316

360 182 750 321

375 190 765 323

55


rubber mixture



Time Interval in seconds

Readings on Dial Gauge

Time Interval in seconds

Dial gauge reading

15 15 525 301

30 22 540 309

45 39 565 315

60 43 580 322

75 65 595 329

90 72 600 336

105 80 615 345

120 94 630 354

135 105 645 360

150 115 660 368

165 119 675 372

180 124 690 380

195 130 705 388

210 135 720 392

225 142 735 402

240 147 750 410

255 154 765 412

270 161 780 413

285 175 795 413

300 181 810 414

315 189 825 415

330 196 840 416

345 201 855 417

360 207 870 418

375 215 885 418

390 222 900 418

405 229

420 235

435 246

450 255

465 267

480 278

495 284

510 292


rubber mixture

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.

57

Chapter six

5.1 Analysis:

Area of Shear box = 59.73mm x 59.83mm = 3.573𝑚2x10−3

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

3.573𝑚2x10−3 x 0.03784m = 1.35226x10−4𝑚3

Density of Sand =𝑀𝑎𝑠𝑠 𝑜𝑓 𝑆𝑎𝑛𝑑

𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑆𝑎𝑛𝑑 Equation 3

.1913𝑘𝑔

1.35226𝑥10−4𝑚3 = 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

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


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

Sh

ea

r str

ess k

pa

Normal Stress Kpa

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

60

5.3 Calculation of Experiment No. 2 (5% of tyre-rubber):


9.604 8.21

14.604 10.94

19.604 13.61



Vertical Load

Kg


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



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

Sh

ea

r str

ess K

pa

Normal Stress

61

Cohesion = 7.5Kpa


Tan = P/B

Tan = 1.5

4.2, = 19.650




9.604 9.925

14.604 12.96

19.604 15.78



Vertical Load

Kg


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


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


Tan = P/B

Tan = 1.2

4.4

= 15.250




9.604 7.32

14.604 9.99

19.604 12.54


0

5

10

15

20

25

30

35

40

45

50

0 10 20 30 40 50 60

Sh

ea

r str

ess K

pa

Normal stress Kpa

63


Vertical Load

Kg


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




cohesion has decreased as compared to 10% of rubber but is still higher than 0% of

rubber content in sand.

Cohesion = 6.5Kpa


Tan = P/B

Tan = 0.9

3.1

= 16.180


0

5

10

15

20

25

30

35

40

0 10 20 30 40 50 60

Sh

ea

r S

tre

ss K

pa

Normal stress Kpa

64



9.604 7.05

14.604 9.69

19.604 12.56



Vertical Load

Kg


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




cohesion has decreased as compared to 15% of rubber

Cohesion = 4.96Kpa


0

5

10

15

20

25

30

35

40

0 10 20 30 40 50 60

Sh

ea

r str

ess K

pa

Normal Stress kpa

65

Tan = P/B

Tan = 0.98

3.1

= 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

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%

Coh

esio

n

Rubber Content

0

5

10

15

20

25

0% 5% 10% 15% 20%

An

gle

of F

riction

Rubber Content

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.

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

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.

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.

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.

http://www.waste-management-world.com/articles/2003/07/scrap-tyre-recycling.html

http://www.waste-management-world.com/articles/2003/07/scrap-tyre-recycling.html

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, John. Wiley & Sons, Inc. New York. 3. Scott. C.R, 1980. An Introduction to Soil Mechanics and Foundations.3rd. Ed. Applied Science Pub., London.

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


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

74


Time interval

Dial gauge Readings

Time interval

Dial gauge Readings

15 5 390 290

30 24 405 292

45 35 420 293

60 54 435 311

75 65 450 318

90 75 465 325

105 84 480 333

120 94 495 341

135 109 510 351

150 115 525 359

165 129 540 362

180 143 555 369

195 155 570 371

210 162 585 376

225 173 600 381

240 195 615 382

255 205 630 383

270 213 645 383

285 230

300 244

315 253

330 260

345 279

360 283

375 287


75


Time interval

Dial gauge Readings

Time interval

Dial gauge Readings

15 28 390 410

30 59 405 414

45 84 420 418

60 98 435 430

75 120 450 440

90 138 465 449

105 162 480 456

120 175 495 460

135 188 510 474

150 218 525 478

165 230 540 481

180 254 555 483

195 271 570 488

210 281 585 491

225 293 600 493

240 299

255 314

270 326

285 338

300 344

315 356

330 370

345 384

360 393

375 405


Analysis:


9.604 7.77

14.604 11.53

19.604 14.79

Table 32. shows the computed peak shear by applying vertical load

76


Vertical Load

Kg


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

Shea

r St

ress

Kp

a

Normal Stress Kpa

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Dissertation FD11