rice husk ash

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THESIS SUBMITTED IN THE PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE AWARD OF THE DEGREE OF MASTER OF CIVIL ENGINEERING IN SOIL MECHANICS AND FOUNDATION ENGINEERING. By GOURHARI BISWAS EXAM ROLL NO- M4CIV10-12. Under The guidance of Prof. S.Chakborti & Prof. S.P.Mukherjee Department of Civil Engineering Faculty of Engineering & Technology Jadavpur University Kolkata-700032

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soil engineering

Transcript of rice husk ash

  • THESIS SUBMITTED IN THE PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE AWARD OF THE DEGREE

    OF

    MASTER OF CIVIL ENGINEERING

    IN SOIL MECHANICS AND FOUNDATION ENGINEERING.

    By

    GOURHARI BISWAS

    EXAM ROLL NO- M4CIV10-12.

    Under The guidance of

    Prof. S.Chakborti &

    Prof. S.P.Mukherjee

    Department of Civil Engineering Faculty of Engineering & Technology

    Jadavpur University Kolkata-700032

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    Department of Civil Engineering Faculty of Engineering & Technology

    Jadavpur University

    CERTIFICATE OF APPROVAL* The foregoing thesis is hereby approved as a creditable study of an

    engineering subject carried out and presented in a manner satisfactory to

    warrant its acceptance as a pre-requisite to the degree for which it has been

    submitted. It is understood that by this approval the undersigned do not

    necessarily endorse or approve any statement made, opinion expressed or

    conclusion drawn therein, but approve the thesis only for the purpose for

    which it is submitted.

    FINAL EXAMINATION FOR 1.

    EVALUATION OF THESIS

    2.

    3.

    (Signatures of Examiners)

    *Only in case the thesis is approved.

    Department of Civil Engineering

    Faculty of Engineering & Technology

    Jadavpur University

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    Certificate

    We hereby recommend that the thesis prepared under our supervision by

    Gourhari Biswas, entitled SOME STUDIES ON STABILIZATION OF

    SUBGRADE OF FLEXIBLE PAVEMENT WITH RICE HUSK, RICE HUSK ASH AND

    LIME be accepted in partial fulfillment of the requirement for the Degree

    of Master of Civil Engineering in Soil Mechanics & Foundation

    Engineering from Jadavpur University.

    In-Charge of Thesis

    Countersigned:

    Head of the Department:

    (Civil Engineering Department)

    Dean:

    (Faculty of Engineering & Technology)

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    ACKNOWLEDGEMENTACKNOWLEDGEMENTACKNOWLEDGEMENTACKNOWLEDGEMENT

    I am extremely thankful and indebted to Prof. S.Chakraborti, Head, Civil Engineering

    Department and Prof. S.P.Mukherjee, Section-in-Charge, Soil Mechanics & Foundation

    Engineering Division of Civil Engineering Department, Jadavpur University, for their

    valuable guidance, constant support and encouragement throughout my thesis work.

    I also express my gratitude to all the faculty members of civil engineering department of

    Jadavpur University for their encouragement and moral support extended throughout my

    thesis work.

    I sincerely acknowledge the help from Mr. Rabin Pal, Mr. Apurba Banerjee and Mr. Ranjit

    Kushari, Laboratory Technical staffs of Soil Mechanics Laboratory and Mr. Debasis of

    Road Materials Laboratory and laboratory attendants Brindaban Naskar and Basudev

    Goari of soil Mechanics laboratory of Civil Engineering Department, Jadavpur University,

    Kolkata.

    I am grateful to my family members, specially my wife and my sons for being with me in

    the hard time that was needed to complete this thesis.

    Last but not the least, I express my heartfelt thanks to all of my classmates, Soil Mechanics

    and Foundation Engineering section, whose friendship, cooperation, and suggestions

    have helped me to complete this thesis work .

    Kolkata

    GOURHARI BISWAS (ROLL NO 000810402013).

    EXAM. ROLL NO : M4CIV-10-12.

    DEPARTMENT OF CIVIL ENGINEERING.

    FACULTY OF ENGINEERING &TECHNOLOGY.

    JADAVPUR UNIVERSITY

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    Abstracts

    With the increase in road construction activities under different Govt.

    schemes, an intense need has been arisen to economize the cost of

    construction. As the subgrade supports the road pavements and the load

    coming from the moving vehicles, improving the quality of natural weak

    subgrade to enhance its strength and load bearing capacity and other

    engineering properties as well will be a most essential part of economizing

    construction activities.

    The quality of a pavement depends on the strength of its sub-grade. The

    subgrade, the layer of soil on which the pavement is built, acts as a support

    for the entire pavement system. In case of the flexible pavement the sub-

    grade must be uniform in terms of geotechnical properties like shear

    strength, compressibility etc. Materials selected for use in the construction of

    sub-grade must have to be of adequate strength and at the same it must be

    economical for use. The materials selected must also be ensured for the

    quality and compaction requirements. If the natural soil is very soft it needs

    some improvement to act as a sub-grade. It is, therefore, needed to replace

    the natural soil by stabilization with improved strength and compressibility

    characteristics.

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    The paper highlights the effect of stabilization of low strength cohesive

    soil with admixture of different materials like Rice Husk Ash, lime etc, which

    are cheap and easily available.

    The present investigation has been carried out with agricultural waste

    materials like Raw Rice Husk (RRH) and Rice Husk Ash (RHA) individually

    mixed with soil and also in combination with different percentage of Hydrated

    Lime with several mix proportions to study improvement of weak road

    subgrade. 5,10,15 and 20 percentages of RHA were mixed with soil

    stabilized with 3,6,9,12 and 15 percentage of lime in different combinations

    and also 2,3,4,5 and 6 percentage of RRH were mixed with soil stabilized

    with 6,9 and 12 percentage lime in several combinations and compacted at a

    water content of OMC+5% and tested for California Bearing Ratio(CBR) and

    Unconfined Compressive Strength(UCS) tests. The results show marked

    improvement in CBR & UCS values of the mixed soils in comparison with that

    of the original soil. The high percentage of siliceous materials present in RHA

    promises it to be used as a potential ground stabilizing/improving materials.

    The effect of curing of specimens were also investigated. It has been found

    that with increase in curing period UCS values as well as CBR value of lime

    RHA stabilized soil as well as lime RRH stabilized soil are increasing

    remarkably.

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    .

    The main testing parameters selected for evaluation of improvement

    and or comparison with that of the original properties of soil

    were CBR tests (both soaked and unsoaked) and Unconfined Compressive

    strength test as the CBR values give the most reliable information about the

    quality of subgrade and its strength characteristics and UCS values give the

    information about the effectiveness of stabilization. As a general rule for a

    given type of stabilization, the higher the compressive strength and CBR

    values the better is the quality of stabilized and compacted materials

    The results of the test experiments promise not only RRH and RHA may be

    used as a potential ground improving materials but also to reduce partially

    the disposal hazard of waste material like RRH and RHA.

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    CONTENTS

    TOPICS PAGES

    Chapter One: Introduction 1-2

    Chapter Two: Review of Literature 3-9 2.0 General 3

    2.1 Literature Review on use of Rice Husk Ash 3 2.2 Literature Review on Use on Raw Rice Husk (RRH) 8

    Chapter Three : Materials Used 10-15 3.1 Soil 10

    3.2 Lime 11 3.3 Rice husk 12

    3.4. Rice husk ash 14

    Chapter Four : Objective and scope of the work 16-17 4.1 Objectives 16

    4.2. Scopes 16

    Chapter Five : Test program 20-23 5.0 General 20 5.1 Test Program 20

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    Chapter Six : Test procedures 24-25 6.0- General 24 6.1 Name of the tests and the relevant IS code 24

    Chapter Seven : Presentation of test results 26-145 7.0 General 26 7.1- Evaluated geotechnical properties of Original Soil 26 7.2. Results for Characterization test of stabilized soil 28 7.3 Compaction characteristics of Unstabilized and

    stabilized soil 38

    7.5 Strength characteristics of soil 65

    7.6 Comparison of CBR test results with cured and

    uncured specimens 139

    7.7 Effect of curing on strength properties of soil 141

    Chapter Eight : Interpretation of test results 146-164 8.0 General 146 8.1- Characteristics of original Soil 146

    8.2 Characterization of unstabilized as well as

    stabilized soils 147

    8.3 Compaction Characteristics of Stabilized Soil- 150

    8.3.1 Effect of Lime addition on Compaction

    Characteristics of soil 150

    8.3.2 Effect of RHA addition on Compaction

    Characteristics of soil 151

    8.3.3Effect of Lime and RHA addition on

    CompactioCharacteristics of soil 151

    8.3.4 Effect of RRH addition on Compaction

    Characteristics of soil 151

    8.3.5 Effect of Lime and RRH addition on

    Compaction Characteristics of soil 152

    8.4 Strength characteristics of Stabilized soil 152

    8.4.0-General

    8.4.1 Effect of Lime addition on strength

    characteristics of soil 153

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    8.4.1.1-Effect on CBR 153

    8.4.1.2-Effect on UCS 153

    8.4.2 Effect of RHA addition on strength

    characteristics of soil 154

    8.4.2.1-Effect on CBR 154

    8.4.2.2-Effect on UCS 155

    8.4.3 Effect of RHA Lime addition on strength

    characteristics of soil 155

    8.4.3.1-Effect on CBR 155

    8.4.3.2-Effect on UCS 156

    8.4.4 Effect of RRH addition on strength

    characteristics of soil 157

    8.4.4.1-Effect on CBR 157

    8.4.4.2 Effect on UCS 158

    8.4.5 Effect of RRH Lime addition on strength

    characteristics of soil 158

    8.4.5.1 Effect on CBR 158

    8.4.5.2. Effect on UCS 160

    8.5 Effect of Curing on Strength properties of soil 161

    8.5.1 Effect of Curing of specimens on CBR values

    8.5.2 Effect of Curing of specimens on UCS values 161

    8.6 Comparison of test results and evaluation

    of Improvement 162

    8.7Effect of admixtures on deformation

    pattern of specimens 164

    Chapter nine : Summary and conclusion 165-168 9.0; - General 165 9.1 Summary 165 9.2 Conclusions 166 9.2.1- Use of Lime 166 9.2.2-Use of Rice Husk Ash (RHA) 166 9.2.3 Use of Raw Rice Husk (RRH) 167

    9.3- Addition of Lime with RHA and RRH 167

    9.3.1. Addition of Lime with RHA 168

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    9.3.2. Addition of Lime with RRH 168

    Chapter Ten : Scope of future work 170-171 10.1 General 170

    10.2 Scopes for future work 170

    References 172-174

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    CHAPTER ONE

    INTRODUCTION

    Soils are deposited or formed by nature under different environmental conditions. Man

    does not have any control on the process of soil formations. As such soil strata at a site

    are to be accepted as they are and any construction has to be adapted to suit the subsoil

    conditions. The existing soil conditions at a given site may not be suitable for supporting

    the desired facilities such as buildings, bridges, dams, roads and so on because the safe

    bearing capacity of a soil may not be to support the given load. Here comes the need to

    explore possibilities for improving the existing soft/weak ground by adopting different

    artificial means.

    Geotechnically soil improvement could either be by modification or stabilization or both.

    Soil modification is the addition of a modifier (lime, cement etc.) to a soil to

    change/improve its engineering properties, while soil stabilization is the treatment of soils

    to enable their strength and durability to be improved such that they become totally

    suitable for construction beyond their original classification.

    Ground improvement in soil in soil has five major functions:

    To increase the bearing capacity of weak soil

    To control deformations and accelerate consolidations

    To provide lateral stability

    To form seepage cut-off and environment control

    To increase resistance against liquefaction

    These functions can be accomplished by modifying the grounds character with or without

    the addition of foreign materials. Improving the ground at the surface is Usually easy to

    accomplish and relatively inexpensive. When at depth, however, the task becomes more

    difficult, usually requiring more rigorous analysis and the use of specialized equipments

    and construction procedures.

    Several methods of soil improvement using pozzolanic materials have been developed

    and used successfully in practice. It has been applied in a variety of civil engineering

    works, like in the construction of base courses where good materials are not economically

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    available, for reducing the permeability and compressibility of soils in hydraulic and

    foundation works, for stabilization of slopes, embankments and excavations. Due to rapid

    industrialization throughout the world the production of huge quantity of waste materials

    create not only the environmental problem but also depositional hazards. Safe disposal of

    the same is a very vital issue and such situation can be addressed by the bulk utilization

    of these materials mainly in the field of civil engineering applications. In recent years the

    use of various waste products in civil engineering construction has gained considerable

    attention in view of the shortage and high costs of conventional construction materials, the

    increasing costs of waste disposal and environmental constraints. A considerable amount

    of research works concerning stabilization of soil with additives such as cement, lime, fly

    ash bitumen etc is available in the literature. But soil stabilization with lime and rice husk

    ash or lime and raw rice husk is relatively a new method, specially lime and raw rice husk

    stabilization a completely new idea.

    In recent times the demand for suitable subgrade materials has increased due to

    increased constructional activities in the road sector and also the paucity of nearby lands

    to allow to excavate fill materials for making subgrade .Again soft soil deposits are

    problematic and needs large scale displacement to facilitate road construction works.

    Such mass replacement methods which are cost and labour intensive can be avoided if

    the poor soil is being improved or modified in situ and reused as road construction

    materials. Different alternative generated waste materials which cause not only

    environmental hazards but also the depositional problems. Some of these materials can

    be economically and suitably used as admixtures or stabilizers for improving soft or weak

    soil so as to make it fit for use as road subgrade materials. The modified soft to be used

    for road construction work should be in line with the practice of engineering in an

    environment friendly and sustainable way.

    Over the years the two main materials for stabilizing, lime and cement have rapidly

    increased in costs. The over dependence on the industrially manufactured soil improving

    additives (cement, lime etc.) have kept the cost of construction of stabilized road

    financially high. The use of agricultural wastes (such as Rice Husk, Rice Husk Ash etc.)

    will considerably reduce the cost of construction and also the environmental and disposal

    hazards they cause.

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    CHAPTER TWO

    REVIEW OF LITERATURE

    2.0 General:-

    In this chapter an attempt has been made to present a review of past works carried out so

    far by different researchers on the relevant topic. The works on Rice Husk Ash and Raw

    Rice Husk ash as soil stabilizing materials are reported in the following section in

    chronological order. Although a number of researchers have attempted soil stabilization

    with Rice Husk Ash but soil stabilization with Raw Rice Husk is almost an unexplored field

    specially the combined use of raw rice husk and lime for soil stabilization.

    2.1 Literature Review of Use on Rice Husk Ash (RHA)

    Brooks et al (2009) carried out experiments to study the effect of mixing RHA and fly ash

    with expansive soil in an effort to upgrade it as a construction material. He investigated the

    potential of RHA-fly ash blend as a swell reduction layer between the footing of a

    foundation and road subgrade. A cost comparison was also made for the preparation of

    the sub base of a highway project with and without the admixture stabilizers. From his

    experimental work he came to the following conclusion:

    1. Stress strain behavior of unconfined compressive strength showed that failure stress

    and strains increased by 106% and 50% respectively when the flyash content was

    increased from 0 to 25%.

    2. When the RHA content was increased from 0 to 12%, Unconfined Compressive Stress

    increased by 97%.

    3. When the RHA content was increased from 0 to 12%, CBR improved by 47%.

    4. The optimum RHA content was found at 12% for both UCS and CBR tests.

    Okafor et al (2009) performed laboratory experiments to study the effects of RHA on

    some geotechnical properties of a lateritic soil to be used for subgrade. Their investigation

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    included evaluation of properties such as compaction, consistency limits and strength of

    the soil with RHA content of 5%, 7.5%, 10%, and 12.5%y soil. They concluded as follows:

    1. The soil was classified to be A-2-6(0) or well-graded sand (SW).

    2. RHA increased the OMC but decreased the MDD of the soil.

    3. The increase in RHA content decreased the plasticity index of the soil. This confirms

    that

    the activity of the mixture reduced with the addition of RHA.

    4. The addition of RHA increased the volume stability of the soil.

    5. The addition of RHA improved the strength property (CBR) of the soil.

    6. 10% RHA content was observed to be the optimum content for the lateritic soil.

    7. From the foregoing investigation it would appear that RHA perform satisfactorily as a

    cheap stabilizing agent for lateritic soil for sub-grade purposes.

    Alhassan(2008) carried out extensive laboratory experiments to investigate the effect of

    lime and RHA on permeability and strength properties of lateritic soils. In his experiments

    A-7-6 lateritic soil(CH) was treated at British Standard Light (BSL) compaction energy with

    upto 8% lime content (by dry weight of soil) at 2% variations and each was admixed with

    upto 8% RHA at 2% variations. Effects of the ash on the soil lime mixtures were

    investigated with respect to Unconfined Compressive Strength (UCS) and coefficient of

    permeability. The UCS of the specimens increased with increasing RHA content at

    specified lime contents to their maximum values at 6% RHA and also the coefficient of

    permeability of cured specimens decreased with increase in ash content to their minimum

    values at 6% RHA content and beyond this point the permeability rises slightly. His

    findings indicate that no more than 6% RHA can be used to increase UCS and reduce

    permeability of lateritic soil.

    Alhassan(2008) again carried out experiments to study the effect of stabilizing A-7-6

    lateritic soil(CH) with 2-12% RHA by weight of dry soil. CBR and UCS tests were

    conducted for the soil RHA composites. The results obtained indicate a general decrease

    in the maximum dry density and increase in optimum moisture content. There was also

    slight improvement in the CBR and UCS values with increase in RHA content. Peak UCS

    values were recorded at between 6-8% RHA content, indicating a little potential of using 6-

    08% RHA for strength improvement of A-7-6 lateritic soil.

    Roy et al (2008) carried out experiments to study the effectiveness of utilization of RHA

    and pond ash for improving subgrade for road construction. They have conducted tests on

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    mixed soils with different proportion of pond ash to find out the effect of mixing RHA on

    CBR values of mixed soil. Their findings were as follows : addition of pond ash or RHA

    shows a considerable effect on compaction characteristics of alluvial soil. MDD of mixed

    soil decreases with increase in added percentage of either of pond ash or RHA and OMC

    increases. Soaked CBR increases to a very high value i.e. about three times when RHA

    and pond ash is mixed with virgin soil at the rate of 20% respectively.

    From their experimental studies on effect of mixing various percentage of pond ash and

    RHA to an alluvial soil they have concluded that when 20% of pond ash and 20% RHA

    are mixed to the virgin soil by weight composite mix shows the maximum increase in CBR

    values by around 200% with simultaneous maximum decrease in plasticity index.

    Roy et al (2008) made an experimental study to explore the possibility of improving the

    engineering properties of alluvial soil utilizing waste materials like pond ash and rice husk

    ash and a little quantity of cement. Their experimental results indicated that significant

    improvements in the index properties and CBR values specially soaked CBR value of

    alluvial soil can be achieved by mixing alluvial soil with pond ash and rice husk ash and

    the most cost effective proportion to the above mix was found to be 20:40:40.Further

    experiment with addition of cement to the mix of above combination in 20:60:20 can

    improve the soaked CBR to the largest increase and this proportion can use maximum

    alternative materials attaining soaked CBR value the highest degree.

    Hussain(2008) carried out research work on Influence of pozzolans on mechanical

    properties of cement column. Ground settlement is one of the major crisis in Bankok due

    to low bearing capacity of soft clay soil, causing problems of low stability and high

    settlement. This problem can be overcome by cement columns when part of the port land

    cement was replaced by pozzolans. His research also focuses on finding an effective mix

    design that may be used on construction of cement columns by slurry mixing with

    optimum water cement ratio.

    The test results showed that soft clay treated with cement and a combination of cement-

    pozzolans improved the stability and settlement of the ground by increasing the bearing

    capacity and shear strength of the treated soil. The unconfined compressive strength has

    improved with replacing definite amount of cement by pozzolans at higher binder contents

    (200kg/m3) while showed a decreasing strength with increasing pozzolans percentage at

    lower binder content (100 kg/m3). The setting times of cement column were found to be

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    significantly delayed as compared with those of cement paste. Moreover soil-cement

    treatment with pozzolans used in this study further delayed the setting times. The highest

    strength was achieved by replacing 25% of cement to rice husk ash type-I at a binder

    content of 200kg/m3, while cement-fly ash combination was found to be the most

    economical binder for deep mixing methods giving 30-40% replacement of cement to fly

    ash at binder content of 200 kg/m3. The mechanical properties of treated clayey soil were

    greatly influenced by the presence of pozzolans. Different pozzolans gave different

    strength at different percentage replacement of cement. Cement in combination with fly

    ash was found to be the most economical binder for deep mixing methods.

    Jha et al(2006) carried out series of experiments to evaluate the effectiveness of using

    RHA as a puzzuolanae to enhance the lime treatment of soil. They studied the influence of

    different mix proportions of lime and RHA on compaction, strength properties, CBR values

    and durability characteristics of soil. Their results show that addition of RHA enhances not

    only the strength development but also the durability of lime stabilized soil. They have

    also found that addition of lime and RHA to soil increases the OMC of mixed soil and

    reduces the MDD. Adding RHA enhances the development of UCS of lime stabilized soil.

    Curing period and temperature has a significant effect on on development of UCS when

    RHA ios added to lime stabilized soil. As the curing time and temperature increases the

    rate of strength gain is intensified by addition of RHA. Durability of lime stabilized soil is

    enhanced by addition of RHA. Addition of RHA increases the CBR value considerably for

    both soaked and unsoaked conditions.

    Muntohar(2005) conducted laboratory experiments to study the influence of anount of

    water available for the Lime RHA pozzolanic reaction. He founded that the strength gain of

    stabilized soils is not only influenced by the type and proportion of the stabilizers and its

    curing time, but also by the water content needed to maintain the reaction. The lime RHA

    reaction being pozzolanic will be greatly influenced by the amount of water to react with

    admixtures apart from the proportions of admixtures. His paper presents the results of a

    laboratory study on the UCS of soils stabilized with lime and RHA compacted at OMC

    and at wet and dry side of OMC. The results show that the water content determines the

    UCS characteristics of stabilized and unstabilized soils. The UCS of unstabilized soil is

    affected by the density or unit weight of the compacted soil and the molded moisture

    content. The UCS of stabilized soil decreases with increasing molding water content but it

    is still higher than that of the unstabilized soils. Higher lime content results to a higher

    UCS value. Maximum strength of the stabilized soil is attained at Lime/RHA ratio of .

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    The UCS of the stabilized soil increases significantly about 7-9 times to the unstabilized

    UCS.

    Muntohar(2002) carried out a series of laboratory experiments individually and in

    combination of RHA and lime in stabilizing expansive soils in Indonesia. He found that the

    geotechnical properties of expansive soils improved with addition of RHA and lime. RHA

    and lime altered thew texture of clay soil by reducing the fine particles. The admixtures

    also found to reduce the liquid limit, swelling [potential of expansive soils and also the

    compressibility characteristics . The CBR value enhances with the addition of admixtures.

    Ten percent lime content produced brittle failure under compression whereas soil treated

    with combination of RHA and lime reveled a ductile behavior but the strength increased

    marginally.

    Sivapulliah et al(2004) investigated the possibility of using RHA as a cushion below the

    footing in expansive soil. Placing a cushion below the expansive soil and foundation is an

    attractive proposal for overcoming the problem associated with construction of structures

    over expansive soils such as Indian black cotton soils. Extensive studies on cohesive non

    swelling soil as a cushion have shown that it is ineffective over cycles of swelling and

    shrinkage of soil. They have found that RHA stabilized with 3-9% of lime or 10% of

    cement and cured for about a week develops the properties required for an effective

    cushion material. Stabilized RHA reduces the bandwith of vertical movements of

    expansive soil not only during the first cycle of swelling but also during the subsequent

    cycles of swelling and shrinkage. The reduction increases with the thickness of the

    cushion. They have also found that lime stabilized RHA is more effective than cement

    stabilized RHA.

    Ali et al (2004) carried out an investigation to study the influence of RHA and lime on

    Atterberg limits, strength, compaction swell and consolidation properties of bentonite. The

    results indicated that the plasticity properties of bentonite were significantly modified upon

    the addition of RHA and lime. The RHA and lime have noticeable influence on

    compaction, swell and consolidation properties of bentonite soil particularly at 15% RHA

    and 8% lime contents individually and combinedly at 15% RHA +4% Lime.

    Raju et al(1999) carried out a study on strength characteristics of expansive soils

    stabilized with lime and RHA. They conducted UCS tests and soaked CBR tests for

    different combinations of the stabilizing agents and concluded that 4% lime is very close to

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    the optimum either as the sole additive or with any other secondary additive from the view

    point of optimum efficiency.

    Rahman(1997) conducted a study on the effects of varies cement RHA proportions on

    the geotechnical properties of lateritic soils. The influence of different mix proportions of

    cement and RHA on Atterberg Limits , compaction characteristics, unconfined

    compressive strength, California bearing ratio and swelling of lateritic soils were studied.

    Test results show that lateritic stabilized with cement RHA mixing can be used

    successfully in highway construction. From the point of view of compressive strength,

    CBR and economy his study recommends a mix proportion of 6% RHA+3% cement for

    sub base materials and 6% RHA+6% cement for base materials for optimum results.

    2.2 Literature Review of Use on Raw Rice Husk (RRH)

    Roy (2010) examined the effect of mixing of Rice Husk (RH) with soil to be used as road

    subgrade construction materials. He mixed RH with various proportions of 5%, 10% and

    15% with and studied the effect of addition of RH on compaction characteristics and CBR.

    His test results showed that the OMC changes slightly with addition of RH and the value

    remains within the range of 23 to 26%. However MDD showed a general decreasing value

    of 1.64 to 1.41 with increasing percentage of RH. He evaluated CBR for both freshly

    mixed soil sample and 30 days cured samples for soaked and unsoaked conditions and

    found that CBR of soil decreases when RH is mixed in increasing percentage from 0 to

    15% in both unsoaked and soaked conditions. Test results showed that with addition of

    RH at increasing percentage with the original soil unsoaked CBR decreases from 4.9 to

    3% only, To check the effect of curing on CBR, similar samples were prepared and cured

    for 30 days in desiccators. Test results of cured samples indicated the similar trends as

    that of uncured samples. However curing for 30 days shown improvement of soaked CBR

    compared to that of uncured samples for any proportion of RH.

    Chan et al(2008) studied the effect of Rice Husk on unconfined compressive strength of

    soft clay soil stabilized with small amount cement. Instead of using conventional materials

    like aggregates as the main constituents, the soft soil itself was being modified and used

    as substitute at various layers, simultaneously reducing cost and utilizing the subsoil

    which would have been otherwise removed. A laboratory based approach was adopted in

    his study, where the modified soil specimen were subjected to UCS test upon 14 days of

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    curing. The specimen were prepared using small amount of cement only or cement

    admixed rice husk. The test data indicates that alternative road construction material can

    be produced from modified soft soil, where the initially weak and soft material was

    significantly improved and strengthened. The test results show that for cement modified

    specimens, 5% cement was able to increase the strength of clay by 25%, whereas 10%

    cement addition increases the strength by almost 100%. For cement rice husk

    specimens,5% cement addition displayed negligible improvement with UCS value,

    bordering bat about 20KPa. This suggest that main binding effect resulted in strength

    increase was dominated by cement content. On the other hand, UCS value of the cement

    rice husk specimens with 10% of cement were markedly improved to as high as 150KPa.

    They thus have concluded that for a given cement content there seemed to have an

    optimum percentage of rice husk required to achieve high strength.

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    CHAPTER THREE

    MATERIALS USED

    3.1 Soil

    Soil used in the present investigation has been collected from a pond of near Jadavpur

    University. On visual inspection it was found to be light grey clayey silt. Evaluated

    properties of the soil are shown in table-3.1 below. Based on L.L. and P.I. the soil may be

    classified as CI.

    Table-3 .1- Evaluated properties of original soil

    Sl. No Characteristics Value

    1 Specific Gravity 2.63

    2 Particle Size Distribution(%)

    a)Sand

    b)Silt

    c)Clay

    9

    81

    10

    3 Liquid Limit(%) 48

    4 Plastic limit (%) 26

  • 22

    5 Plasticity Index(%) 22

    6 Classification of soil CI

    7 Maximum Dry Density

    (gm/cc)

    1.61

    8 Optimum Moisture

    Content(%)

    20

    9 Unconfined Compressive

    strength(KN/m2)

    390

    10 Unsoaked CBR(%) 8.3

    11 Soaked CBR(%) 3.36

    12 Swelling Index(%) 14

    3.2 Lime

    Until the invention of Portland cement, lime was used as the chief cementing material in

    the construction field. Usually lime in free state is not found in nature. The raw material for

    the manufacture of lime (CaO) is calcium carbonate which is obtained by the calcinations

    of lime stone.

    Quick Lime-It is the lime obtained after the calcinations of lime stone.

    Hydrated Lime- When the quick lime is sprinkled with water it slakes within 10 minutes

    and becomes powder and the fine powder obtained in the process is called hydrated lime.

    The process is known as hydration of lime.

    CaO + H2O --------- Ca(OH)2 + 15.6 kcal

    On addition of lime to soil two main types of chemical reactions occur:-

    Alteration in the nature of absorbed layers through base exchange phenomenon

    Cementing or pozzolanic action.

    Lime reduces the plasticity index of highly plastic soils making them more friable and easy

    to be handled and pulverized. It also reduces the shrink swell properties of expansive soil.

    The plasticity index of soils of low plasticity generally increases. There is generally an

    increase in Optimum Moisture Content and decrease in Maximum Dry Density but the

    strength and durability increases. Hydrated (slaked) lime is very useful /effective in

  • 23

    treating heavy, plastic clayey soils. Lime may be used alone or in combination with

    cement, bitumen, fly ash, or other pozzolanic materials like rice husk ash etc. Sandy soils

    may also be stabilized with these combinations. Lime has been mainly used for stabilizing

    the road bases and sub grades. Lime is an unparrelled aid in the modification and

    stabilization of soil beneath road and similar construction projects. Using lime can

    substantially increase the stability, impermeability and load bearing capacity of the

    subgrade. And lime is a proven solution for soil modification and stabilization in USA

    where more than one million metric tons of lime is used annually for this purposes.

    gains. The key to pozolanic reactivity and stabilization is a reactive soil, a good mix design

    protocol, and a reliable construction practices.

    Characteristics of Lime

    Lime possesses good plasticity and is easy to work with

    It stiffens easily and is resistant to moisture

    It has excellent cementitious property

    The shrinkage on drying is small because of its high water retentivity.

    Constituents Wt%

    SiO2 4.11

    Al2 O3 3.11

    Fe2 O3 2.70

    Ca CO3 3.80

    CaO 63.70

    CaSO4 19.26

    MgO 1.62

    Loss on ignition 1.70

    Table-3.2, Chemical composition of Hydrated Lime

    (Source- Dr. H. Katebi, Lime stabilization of Calcareous Soil)

  • 24

    3.3 RICE HUSK

    Rice husk is a major agricultural by product obtained from food crop paddy. It is a most

    commonly available lignocellulosic materials that can be converted into different kinds of

    fuels and chemical feedstocks through a variety of thermochemical conversion processes.

    Generally it was considered earlier a worthless by product of the rice mills. For every four

    tons of rice one ton of husk is produced. The husk is disposed of either by dumping in an

    open heap near the mill site or on the road site to be burnt. Its bulk density ranges from 86

    to 114 Kg/m3. It has high ash content, generally 15 to 24% and the ash has high silica

    content. The silica content of the available ash ranges from 90 to 97%. Rice husk has a

    chemical composition as follows:-

    Sl. No Constituents % by weight

    1. Cellulose 40 - 45

    2. Lignin 25 - 30

    3. Ash 15 - 24

    4. Moisture 8 - 15

    Table-3.3- Chemical composition of Rice Husk

    (Source-Utilization of uncontrolled Burnt Rice Husk Ash in Soil Improvement,

    Agus Setyo Muntohar. Sept. 2002)

    Raw rice husk was collected from a nearby mini rice mill and it was used as they were

    without further processing. This was to ensure minimal preparation procedure for cost and

    labour saving in actual application.

    Using natural materials like rice husk for ground improvement is not a novel idea but

    practiced by early civilization too. Straws, for instance, were mixed and compacted with

    mud to make walls and pathways in olden days. The artificial fibres were included to

    enhance the strength and durability of the earth as construction materials.

  • 25

    3.4. RICE HUSK ASH

    Rice Husk Ash is predominantly a siliceous material annually generated about 4.73

    million tons after burning raw rice husk in a boiler or in open fire. The normal method of

    conversion from rice husk to rice husk ash is by incineration. Burning rice husk generates

    about 15-20% of its weight as ash. Many industries use rice husk as a relatively cheap

    fuel. Concomitantly abundance of the ash (RHA) can be a potential waste product.

    Indonesia produces paddy annually around 50 million tons. The amount of rice husk ash is

    about 12.5 million tons and the ash (RHA) production is about 4 million tons. The ash

    being very light easily is carried by wind and water by in its dry state. It is difficult to

    coagulate and thus contribute to air and water pollution. Cumulative generation of ash

    requires a large space for disposal. Utilization of rice husk ash by exploiting its inherent

    properties is the only way to solve the environmental and disposal problem of rice husk

    ash.

    Chemically RHA consists of 82-87 % of silica, exceeding that of fly ash. Materials

    containing high reactive silica (SiO2) is suitable to be used as lime-pozolana mixes and as

    substitution of port land cement. The high percentage of siliceous materials in the RHA

    makes it an excellent material for soil stabilization. The silica content in the rice husk ash

    (RHA) is dependent on the following:- a) the variety of the rice, b) soil and climate

    conditions, c) prevailing temperature and d) agricultural practices ranging from application

    of fertilizers and insecticides etc.

    A number of researchers has studied the physical and chemical properties of rice husk

    ash (RHA). Rice husk ash can not be used alone for stabilizing soil because of the lack of

    the cementitious properties. The high percentage of siliceous material in RHA indicates

    that it has potential pozzolanic properties. The normal method of conversion of husk to

    ash is incineration. The properties of RHA depend whether the husks have undergone

    complete destructive combustion or have been partially burnt. The RHA has been

    classified into high carbon char, low carbon ash and carbon free ash. The composition

    and properties of rice husk ash is presented in table nos 3.4 and 3.5 below.

  • 26

    Sl. No Components % present in RHA

    1. SiO2 93.2

    2. Al2O3 0.59

    3. Fe2O3 0.22

    4. CaO 0.51

    5. MgO 0.41

    6. K2O 2.93

    7. Loss in Ignition 1.19

    Table-3.4 Composition of Rice Husk Ash(RHA) Used

    Sl. No Property Value

    1. Specific Gravity 1.95

    2. Max. Dry Density 8.5

    3. Optimum Moisture

    Content

    31.8

    4. Angle of Internal Friction 38

    5. Unsoaked CBR(%) 8.75

    6. Soaked CBR(%) 8.15

    Table 3.5- Properties of Rice Husk Ash (RHA)

    Rice husk ash for the present investigation was obtained from a local rice mill at

    Chandpara, North 24 Parganas the properties of which have been listed above.

  • 27

    CHAPTER FOUR

    OBJECTIVES AND SCOPE OF THE WORK

    4.1 OBJECTIVES

    The objectives of the present study are as follows:-

    To determine the applicability, effectiveness and suitability of lime and some locally

    available agricultural waste materials e.g. Raw Rice Husk(RRH) and Rice Husk

    Ash(RHA) in isolation and in different combinations as soil stabilizing materials for

    use in road subgrade.

    To characterize both the unstabilized and stabilized soil by conducting routine

    laboratory tests like specific gravity, Atterberg Limits, grain size analysis etc.

    To determine engineering properties e.g. optimum moisture content (OMC),

    maximum dry density (MDD), California Bearing Ratio (CBR), both unsoaked and

    soaked for both unstabilized and stabilized soil for assessing the improvement of

    soil with stabilization in terms soil strength.

    To find out the best possible design mix proportion of soil and admixtures which

    gives maximum strength of stabilized soil compared to that of the original soil.

    4.2. SCOPES:-

    The scopes of work for the present study is summarized below :-

    Procurement of soft soil, Rice Husk, Rice Husk Ash and lime.

    Conducting routine laboratory tests of original soil, e.g. Liquid Limits, Plastic Limit,

    grain size analysis, specific gravity, bulk density field moisture content, swelling

    index etc. for characterizing the soil.

    Preparation of soil admixtures mixes by percentage of dry weight with appropriate

    preselected proportion as shown in tables 4.1 and 4.2 below.

  • 28

    Table4.1- Details of Mix Proportions of Lime and RHA with Soil

    Mix No Soil (%) Lime (%) RHA (%)

    1.

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    29

    30

    31

    100

    97

    94

    91

    88

    85

    95

    90

    85

    80

    92

    87

    82

    77

    89

    84

    79

    74

    86

    81

    76

    71

    83

    78

    73

    68

    80

    75

    70

    65

    0

    3

    6

    9

    12

    15

    0

    0

    0

    0

    3

    3

    3

    3

    6

    6

    6

    6

    9

    9

    9

    9

    12

    12

    12

    12

    15

    15

    15

    15

    0

    0

    0

    0

    0

    0

    5

    10

    15

    20

    5

    10

    15

    20

    5

    10

    15

    20

    5

    10

    15

    20

    5

    10

    15

    20

    5

    10

    15

    20

  • 29

    Table -4.2 Details of Mix Proportions of Lime and RRH with Soil

    Mix No Soil (%) Lime (%) RRH (%)

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    100

    98

    97

    96

    95

    94

    92

    91

    90

    89

    88

    89

    88

    87

    86

    85

    86

    85

    84

    83

    82

    0

    0

    0

    0

    0

    0

    6

    6

    6

    6

    6

    9

    9

    9

    9

    9

    12

    12

    12

    12

    12

    0

    2

    3

    4

    5

    6

    2

    3

    4

    5

    6

    2

    3

    4

    5

    6

    2

    3

    4

    5

    6

    Conducting routine laboratory tests with different mix proportions as tabulated above.

    Conducting Standard Proctor Test as per IS: 2700(Part-VII),1980/87 on both

    unstabilized and stabilized soil mixes to determine their individual OMC and MDD.

    Conducting Laboratory CBR tests on both unstabilized and stabilized soil mixes as

    tabulated above to find out the CBR value for each of them corresponding to

    2.5mm and 5.0mm penetration after compacting the soil at moisture content 5%

    more than their respective OMC.

    Conducting Unconfined Compressive Strength (UCS) Tests on samples obtained

    by compacting each of the unstabilized and stabilized soil samples at OMC+ 5%

    moisture content in Standard Proctor Mould.

  • 30

    Conducting soaked as well as unsoaked CBR tests on few stabilized soil samples

    after curing for 7 days.

    Conducting UCS tests for all stabilized soil samples after 7 days and 28 days

    curing.

    Comparison of test results and evaluation of improvement of weak soil in terms of

    CBR and UCS value.

  • 31

    CHAPTER FIVE

    TEST PROGRAM

    5.0 General:

    Detailed experimental study was under taken to investigate the characteristics and

    behavior of typical locally available soil mixed with lime and waste materials like Raw

    Rice Husk(RRH) and Rice Husk Ash (RHA) in different percentage and in several

    combinations from the view point of applicability of such materials in road subgrade.

    In view of the above the present experimental study has been aimed at to investigate the

    behavior of soils with additions of alternative materials as detailed below:

    Typical locally available soil

    Typical locally available soil and lime

    Typical locally available soil and RHA

    Typical locally available soil, lime and RHA

    Typical locally available soil and RRH

    Typical locally available soil, RRH and lime

    5.1 Test Program

    5.1.1 Routine tests for characterization such as Liquid Limit, Plastic Limit, Specific gravity,

    Free swell index test etc., compaction characteristics and strength properties of

    unstabilized soil.

    5.1.2 Relevant tests for characterization, compaction characteristics and strength

    properties (CBR and UCS) of stabilized soil.

  • 32

    Detailed test program of the present study has been reported in this section in tables 5.1

    and 5.2 below.

    Table-5.1, Detail test program for Lime RHA mixed soil

    Sl.

    No

    Tes

    t

    No

    Mis

    Proportions

    L.

    L

    P.

    L

    UCS CBR CBR(after 7

    days curing)

    Soil

    (%)

    Li

    me

    (%)

    RH

    A(%

    )

    0d

    ay

    cu

    rin

    g

    7

    day

    s

    curi

    ng

    28

    days

    curin

    g

    unso

    aked

    soa

    ked

    Unso

    aked

    soake

    d

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    22

    23

    24

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    22

    23

    24

    100

    97

    94

    91

    88

    85

    95

    90

    85

    80

    92

    87

    82

    77

    89

    84

    79

    74

    86

    81

    76

    71

    83

    78

    0

    3

    6

    9

    12

    15

    0

    0

    0

    0

    3

    3

    3

    3

    6

    6

    6

    6

    9

    9

    9

    9

    12

    12

    0

    0

    0

    0

    0

    0

    5

    10

    15

    20

    5

    10

    15

    20

    5

    10

    15

    20

    5

    10

    15

    20

    5

    10

  • 33

    25

    26

    27

    28

    29

    30

    25

    26

    27

    28

    29

    30

    73

    68

    80

    75

    70

    65

    12

    12

    15

    15

    15

    15

    15

    20

    5

    10

    15

    20

    Table-5.2- Detail test program for Lime RRH mixed soil

    Sl.

    No

    Te

    st

    No

    Mis Proportions L.

    L

    P.

    L

    UCS CBR CBR(after 7

    days curing)

    Soil(

    %)

    Li

    me

    (%)

    RR

    H(%

    )

    0d

    ay

    cu

    rin

    g

    7

    day

    s

    curi

    ng

    28

    days

    curin

    g

    unso

    aked

    soa

    ked

    Unso

    aked

    soake

    d

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    100

    98

    97

    96

    95

    94

    92

    91

    90

    89

    88

    89

    88

    87

    86

    85

    0

    0

    0

    0

    0

    0

    6

    6

    6

    6

    6

    9

    9

    9

    9

    9

    0

    2

    3

    4

    5

    6

    2

    3

    4

    5

    6

    2

    3

    4

    5

    6

  • 34

    17

    18

    19

    20

    21

    17

    18

    19

    20

    21

    86

    85

    84

    83

    82

    12

    12

    12

    12

    12

    2

    3

    4

    5

    6

  • 35

    CHAPTER SIX

    TEST PROCEDURES

    6.0- General:-

    In this chapter detailed test proc17edures have been presented. All the tests for

    unstabilized soil as well as stabilized soil were carr18ied out as per the procedures laid

    out in the relevant IS code of practice.1920

    6.1 Name of the tests and the relevant IS code followed, have been presented in this

    section in tabular form as below.

    Table-6.1- Name of tests performed and Relevant IS Code followed.

    25Sl. No Name of tests Relevant IS code

    followed

    126 Specific Gravity IS : 2720, Part-3, 1980

    227 Atterberg Limits IS ; 2720, Part -5,1985

    3 Classification and Identification of

    soil

    IS : 2720, Part-1498,1970

    4 Grain size analysis IS : 2720, Part-4,1985

    5 Water content determination IS : 2720, Part -2, 1973

    6 Free swell Index of soil IS : 2720, Part-40,1977

    7 Unconfined Compressive Strength IS : 2720, Part-10,1973

    8 Laboratory CBR IS :2720, Part-16,1979

    9 Water content Dry density

    Relationship using light compaction

    IS :2720, Part-7, 1980

    10 Unconfined compressive strength

    test for stabilized soil

    IS :4332, Part-V, 1970

  • 36

    All the tests of original soil were carried out as per the standard practice as laid out in the

    relevant IS code of practice. For tests of specimens of mixed/stabilized soils , specimens

    were prepared by thoroughly mixing the required quantity of soil and stabilizers in

    preselected proportion in dry state and then required quantity of water was sprinkled and

    mixed thoroughly to get a homogeneous and uniform mixture of soil and admixtures. To

    maintain the homogeneity and uniformity in mix proportions, specimens for both the

    Unconfined compressive strength tests and California Bearing Ratio tests were prepared

    simultaneously, so as to ensure uniformity in materials and water content. Specimens for

    UCS tests were collected from Standard Proctor mould after compacting the same in the

    mould at a moisture content equal to respective OMC plus 5%. For every combinations, 9

    samples were prepared. Three were tested on the same day of preparation of specimens

    and another six specimens were kept in dessicator after putting the specimens in sealed

    plastic bag for 7 days and 28 days testing to investigate the effect of curing.

    For laboratory CBR tests, specimens were prepared in the CBR mould as per the

    standard practice. Immediately after preparation of specimen the same tested for

    unsoaked condition and then it was submerged for four days for soaked tests. Same

    specimens were used for both unsoaked and soaked tests. For every combination of soil

    and stabilizers, two specimens were kept in closed dessicator after covering the same by

    plastic sheet for 7 days. Thereafter the specimens were tested for unsoaked and four days

    soaked tests to investigate the effect of curing.

    For Atterberg limit tests on mixed soils, specimens were prepared by mixing soil and

    stabilizers in dry state as per the preselected proportions thoroughly and then water was

    added as per the standard practice. To investigate the effect of mixing RHA, RHA lime

    combination and also RRH and RRH Lime combination with the original soil to be used for

    construction of road subgrade, RHA was mixed in various proportions of 5%,10%, 15%,

    20% and RRH was mixed in proportions of 2%,3%,4%,5%,and 6% with soil in isolation

    and in combination of lime in the proportions of 3%,6%,9%,12%,15%,with each of the

    percentage of RHA and 6%,9%,12%,respectively with each of the percentage of RRH. To

    determine the moisture content dry density relation ship, CBR and UCS of stabilized soil ,

    Standard Proctor Test (IS 2720, Part-7, 1980) was carried out. Specimens for CBR tests

    was compacted at moisture content equal to OMC plus five percent and for UCS tests

    specimens were collected from Standard Proctor Mould after compacting it at moisture

    content equal toOMC+5%.

  • 37

    CHAPTER SEVEN

    PRESENTATION OF TEST RESULTS

    7.0 - General:-

    In this chapter the results of all the tests carried out have been presented in the following

    sections.

    7.1- Evaluated geotechnical properties of soil

    In this section the evaluated geotechnical properties of the original soil have been

    presented in tabular form in table 6.1 below and the necessary graphs have been

    presented thereafter.

    Table-7.1- Evaluated geotechnical properties of Original Soil

    Sl. No Characteristics Value

    1 Specific Gravity 2.63

    2 Particle Size Distribution(%)

    a)Sand

    b)Silt

    c)Clay

    9

    81

    10

    3 Liquid Limit(%) 48

    4 Plastic limit(%) 26

    5 Plasticity Index(%) 22

    6 Classification of soil CI

    7 Maximum Dry Density (gm/cc) 1.61

    8 Optimum Moisture Content(%) 20

  • 38

    9 Unconfined Compressive strength(KN/m2) 390

    10 Unsoaked CBR(%) compacted at OMC 8.3

    11 Soaked CBR(%) compacted at OMC 3.36

    12 Unsoaked CBR(%) compacted at moisture

    content OMC+5%.

    4.3

    13 Soaked CBR (%) when compacted at

    moisture content OMC+ 5%

    2.6

    14 Swelling Index(%) 14

    Original Soil

    0

    0.5

    1

    1.5

    2

    0 10 20 30 40

    water content(%)

    Dry

    density(g

    m/c

    c)

    Fig 7.1(a)-Dry density moisture content relationship of original

    Grain Size Distribution of Soil

    0

    20

    40

    60

    80

    100

    120

    0.001 0.01 0.1 1 10

    Grain Size ( mm)

    Fig 7.1(b)- Grain size distribution curve of original soil

  • 39

    Unsoaked CBR Test of Soil at 35% water Content

    0

    20

    40

    60

    80

    100

    120

    0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

    Penetration (mm)

    Lo

    ad

    (K

    g)

    Fig 7.1(c) Unsoaked CBR of original soil

    Fig 7.1(d) Soaked CBR of original soil

    6.2. Results for Characterization test of stabilized soil

    Results of laboratory tests for Liquid Limit, Plastic Limit, Plasticity Index properties of

    different mixes of soil with varying percentage of Lime, RHA, Lime and RHA , Raw Rice

    Husk(RRH) and RRH plus Lime for characterization of Unstabilized and Stabilized Soil

    have been presented in this section.

    Soaked CBR Test of Soil at 30% Water Content

    0

    20

    40

    60

    80

    100

    120

    0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

    Penetration (mm)

    Load (Kg)

  • 40

    6.2.1. Consistency limits of soil with varying percentage of Lime are presented in this

    section along with necessary graphical representation.

    Table -7.2, Consistency limits of soil with varying percentage of Lime

    % of Lime Liquid Limit(%) Plastic Limit(%) Plasticity

    Index(%)

    0 48 26 22

    3 55.5 35.2 20.3

    6 56.3 35.9 20.4

    9 58.5 38.3 20.2

    12 59.7 39.2 19.8

    15 60.3 41.5 18.8

    Variation of Plastic Limit with varying

    percentage of lime

    0

    10

    20

    30

    40

    50

    0 5 10 15 20

    % of Lime

    Pla

    sti

    c lim

    it(%

    )

    Plastic Limit(%)

    Fig -7.1(e)

  • 41

    Variation of Liquid Limt with varying

    percentage of Lime

    0

    10

    20

    30

    40

    50

    60

    70

    0 5 10 15 20

    % of Lime

    Liq

    uid

    Lim

    it(%

    )

    Liquid Limt

    Fig 7.1(f)

    Variation of Plasticity Index(%) with varying % of

    Lime

    18

    19

    20

    21

    22

    23

    0 5 10 15 20

    % of Lime

    Pla

    sti

    cit

    y In

    dex(%

    )

    Plasticity Index(%)

    Fig 7.1 (g)

    7.2.2 Consistency Limits of soil with varying percentage of Rice Husk Ash have been

    presented in this section along with graphical representations.

  • 42

    Table-7.3, Consistency Limits of soil with varying percentage of RHA

    % of RHA Liquid Limit(%) Plastic Limit(%) Plasticity Index(%)

    0 48 26 22 5 56.6 37.2 19.4 10 58.3 39.4 18.9 15 61.7 43.95 17.75 20 63.5 45.69 17.81

    Variation of Liquid Limit with varying % of RHA

    0

    10

    20

    30

    40

    50

    60

    70

    0 5 10 15 20 25

    % of RHA

    Liq

    uid

    Lim

    it(%

    )

    Liquid Limit

    Fig 7.1(h)

    Varyiation of Plastic Limit(%) with varying % of

    Lime

    0

    10

    20

    30

    40

    50

    0 5 10 15 20 25

    % of Lime

    Pla

    sti

    c L

    imit

    (%)

    Plastic Limit(%)

  • 43

    Fig7.1 (i)

    Variation of Plasticity Index with varying % of

    RHA

    0

    5

    10

    15

    20

    25

    0 5 10 15 20 25

    % of RHA

    Pla

    sti

    cit

    y In

    dex(%

    0Plasticity Index

    Fig 7.1(j)

    7.2.3 Consistency Limits of soil with lime and RHA addition have been presented in this

    section along with graphical representations

    Table-7.4, Consistency Limits of soil with varying percentage of Lime and RHA

    Soil(%) Lime(%) RHA(%) L.L(%) P.L.(%) P.I(%) 100 0 0 48 26 22 92 3 5 56.5 38.2 18.3

    87 3 10 57.3 39.3 18 82 3 15 58.5 41.1 17.4 77 3 20 60.4 42.4 18 89 6 5 57.5 38.6 18.9 84 6 10 59.3 39.2 20.1 79 6 15 61.5 41.3 20.2

    74 6 20 62.5 43.2 19.3 86 9 5 59.6 41.1 18.5 81 9 10 60.4 42.5 17.9 76 9 15 61.3 43.2 18.1

  • 44

    71 9 20 63.2 43.6 19.6 83 12 5 59.3 41.5 17.8 78 12 10 61.5 42.9 18.6

    73 12 15 63.5 43.2 20.3 68 12 20 64.3 44.5 19.8 80 15 5 60.4 42 18.4 75 15 10 62.6 42.8 19.8 70 15 15 64.5 43.7 20.8 65 15 20 66.2 45.2 21

    Variation of Liquid Limit with varying % of RHA

    for a given % of Lime

    0

    10

    20

    30

    40

    50

    60

    70

    0 10 20 30

    % of RHA

    Liq

    uid

    Lim

    it(%

    )

    L.L. for 3% Lime

    content

    L.L for 6% Lime

    L.L. for 9% Lime

    content

    L.L. for 12% Lime

    content

    L.L.for 15% Lime

    content

    Fig 7.2(a)

  • 45

    Variation of Plastic Limit with varying % of RHA

    for a given % of Lime

    0

    10

    20

    30

    40

    50

    0 10 20 30

    % of RHA

    Pla

    sti

    c L

    imit

    (%)

    P.L. for 3% Lime

    content

    P.L.for 6% Lime

    content

    P.L.for 9% Lime

    content

    P.L for 12% Lime

    content

    P.L.for 15% Lime

    content

    Fig 7.2(b)

    Variation of Plasticity Index of soil with varying

    % of RHA for a given % of Lime

    0

    5

    10

    15

    20

    25

    0 10 20 30

    % of RHA

    P.I.(

    %)

    P.I. for 3% Lime

    content

    P.I.for 6% Lime

    content

    P.I.for 9% Lime

    content

    P.I.for 12% Lime

    content

    P.I. for 15% Lime

    content

    Fig 7.2(c)

    7.2.4- Consistency Limits of soil with varying percentage of Raw Rice Husk(RRH)

    addition have been presented in this section along with necessary graphical

    representation.

    Table-7.5- Consistency Limits of Soil with varying percentage of Raw

    Rice Husk

  • 46

    % RRH L.L(%) P.L.(%) P.I(%)

    0 48 26 22

    2 59.2 37 22.2

    3 60.5 38.2 22.3

    4 62.2 39.4 22.8

    5 63 40.3 22.7

    6 64.4 42.1 22.3

    Variation of Liquid Limit with varying % of RRH

    0

    10

    20

    30

    40

    50

    60

    70

    0 2 4 6 8

    % OF RRH

    Liq

    uid

    Lim

    it(%

    )

    Liquid Limit

    Fig 7.3(a)

  • 47

    Variation of Plastic Limitwith varying % of RRH

    0

    5

    10

    15

    20

    25

    30

    35

    40

    45

    0 2 4 6 8

    % OF RRH

    Pla

    sti

    c lim

    it(%

    )Plastic Limit

    Fig7.3 (b)

    Variation of Plasticity Index with varying % of

    RRH

    21.8

    22

    22.2

    22.4

    22.6

    22.8

    23

    0 2 4 6 8

    % of RRH

    Pla

    sti

    cit

    y In

    dex(%

    )

    Plasticity Index(%)

    Fig 7.3(c)

    7.2.5 Consistency Limits of soil with varying percentage of Lime and RRH addition have

    been presented in this section along with necessary graphical representation.

    Table-7.6, Consistency Limits of soil with varying percentage of Lime and RRH

  • 48

    Soil(%) Lime(%) RRH(%) L.L.(%) P.L.(%) P.I.(%)

    100 0 0 48 26 22

    6 2 56 39 17

    6 3 57.2 39.4 17.8

    6 4 58.1 41.2 16.9

    6 5 59 42 17

    6 6 59.3 39.5 19.8

    9 2 58 41.9 16.1

    9 3 58.8 41.8 17

    9 4 59.2 42.4 16.8

    9 5 60.7 43 17.7

    9 6 62.2 42.9 19.3

    12 2 62 43.3 18.7

    12 3 62.9 44.3 18.6

    12 4 63.4 45.1 18.3

    12 5 64.2 46 18.2

    12 6 65.6 46.6 19

    Variation of Liquid Limit with varying % of RRH

    for a given % of Lime

    0

    10

    20

    30

    40

    50

    60

    70

    0 2 4 6 8

    % of RRH

    Liq

    uid

    Lim

    it(%

    ) L.L.for 6% Lime

    content

    L.L.for 9% of Lime

    content

    L.L. for 12% Lime

    content

    Fig 7.4(a)

  • 49

    9

    Variation of P.L. for varying % of RRH for a

    given % of Lime

    0

    10

    20

    30

    40

    50

    0 2 4 6 8

    % of RRH

    P.L

    (%

    )

    P.L. for 6% of Lime

    P.L. for 9% of Lime

    P.L. for 12% of

    Lime

    Fig 7.4(b)

    Variation of P.I. for varying % of RRH with a

    given % of Lime

    0

    5

    10

    15

    20

    25

    0 2 4 6 8

    % of RRH

    P.I.(

    %)

    P.I. FOR 6% of Lime

    P.I. for 9% of Lime

    P.i. FOR 12% OF

    lIME

    Fig 7.4 (C)

    7.3 Compaction Characteristics of Unstabilized and Stabilized Soil

    In this section results of Compaction Characteristics of unstabilized and Stabilized Soil

    obtained from Standard Proctor tests have been presented in tables and graphs.

    7.4.1 Compaction characteristics of Unstabilized soil

  • 50

    Fig 7.5(a)

    7.4.2 Compaction characteristics of Soil with varying percentage of Lime have been

    presented in this section along with necessary graphical representation in table 6.7.

    Table -7.7 Compaction characteristics of soil with varying percentageof Lime

    Sl. No % of Lime O.M.C(%) Max.Dry Density(gm/cc)

    1 0 20 1.61

    2 3 22 1.51

    3 6 22.5 1.46

    4 9 23 1.45

    5 12 25 1.43

    6 15 26.2 1.42

  • 51

    Fig 7.5(b)

    Soil +6% Lime

    1.2

    1.25

    1.3

    1.35

    1.4

    1.45

    1.5

    0 5 10 15 20 25 30

    Water Content (%)

    Dry

    Density(g

    m/c

    c)

    Fig 7.5(c)

  • 52

    OMC+15% Lime

    1.25

    1.3

    1.35

    1.4

    1.45

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

    Soil + 9% Lime

    0

    0.5

    1

    1.5

    2

    0 10 20 30 40

    Water Content(%)

    DR

    Y

    DE

    NS

    ITY

    (gm

    /cc)

    Fig 7.5(d)

    Soil +12% Lime

    1.3

    1.32

    1.34

    1.36

    1.38

    1.4

    1.42

    1.44

    0 10 20 30 40

    Water Content(%)

    Dry

    Density(g

    m/c

    c)

    Fig 7.5(e)

    Fig7.5(f)

  • 53

    7.4.3. Compaction characteristics of soil with varying percentage of RHA

    Compaction Characteristics of Soil with varying percentage of RHA have been presented

    in this section along with necessary graphical representation in table 7.8.

    Table- 7.8, Compaction characteristics of Soil with varying percentage of RHA

    Sl.No %of RHA OMC(%) Max.Dry Density(gm/cc)

    1 0 20 1.61

    2 5 23.5 1.43

    3 10 25.4 1.39

    4 15 28.3 1.35

    5 20 30.8 1.29

    Soil + 5% RHA

    1.3

    1.35

    1.4

    1.45

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

    Fig 7.6(a)

  • 54

    Soil +10% RHA

    1.15

    1.2

    1.25

    1.3

    1.35

    1.4

    0 10 20 30 40

    Water Content (%)

    Dry

    density

    (gm

    /cc)

    Fig7.6 (b)

    OMC +15% RHA

    1.15

    1.2

    1.25

    1.3

    1.35

    0 10 20 30 40 50

    Wqater Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.6(c))

    Soil +20% RHA

    1.1

    1.15

    1.2

    1.25

    1.3

    0 10 20 30 40 50

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

  • 55

    Fig 7.6 (d)

    7.4.4 Compaction Characteristics of soil with varying combination of Lime and RHA have

    been presented in this section in table 7.9 along with necessary graphical representation.

    Table -7.9, Compaction charactertistics of Soil with varying percentage of Lime and

    RHA

    Sl No Soil(%) Lime(%) RHA(%) OMC(%0 Mdd(gm/cc)

    1 3 5 25 1.41

    2 3 10 27.2 1.38

    3 3 15 29.1 1.33

    4 3 20 30.9 1.29

    5 6 5 26 1.39

    6 6 10 27.5 1.36

    7 6 15 30.2 1.32

    8 6 20 32.4 1.28

    9 9 5 28 1.39

    10 9 10 29.5 1.36

    11 9 15 31.2 1.3

    12 9 20 32.8 1.26

    13 12 5 28.9 1.37

    14 12 10 30.7 1.34

    15 12 15 31.9 1.29

    16 12 20 33.1 1.25

    17 15 5 29.3 1.35

    18 15 10 30.9 1.31

    19 15 15 32.1 1.27

    20 15 20 33.6 1.23

  • 56

    Soil+3% Lime +5% RHA

    1.28

    1.3

    1.32

    1.34

    1.36

    1.38

    1.4

    1.42

    0 10 20 30 40

    Water Content (%)

    Dry

    De

    nsity(g

    m/c

    c)

    Fig 7.7(a)

    Soil+3 %Lime+ 10% RHA

    1.2

    1.25

    1.3

    1.35

    1.4

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

    Fig 7.7 (b)

  • 57

    Soil+3% Lime +15% RHA

    1.15

    1.2

    1.25

    1.3

    1.35

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.7(c)

    Soil+3% Lime+20% RHA

    1.1

    1.15

    1.2

    1.25

    1.3

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.7 (d)

    Soil+6% Lime+5% RHA

    1.26

    1.281.3

    1.32

    1.34

    1.361.38

    1.4

    0 10 20 30 40

    Water Content(%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.7(e)

  • 58

    Soil +6% Lime+10% RHA

    1.2

    1.25

    1.3

    1.35

    1.4

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.7(f)

    Soil+6% Lime+15% RHA

    1.21.221.241.261.28

    1.31.321.34

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig7.7(g)

    Soil+6% Lime+20% RHA

    1.1

    1.15

    1.2

    1.25

    1.3

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.7 (h)

  • 59

    Soil+9% Lime+5% RHA

    1.25

    1.3

    1.35

    1.4

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.7(i)

    Soil+9% Lime+10% RHA

    1.2

    1.25

    1.3

    1.35

    1.4

    0 10 20 30 40

    Water Comtent (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.7(j)

    Soil+9% Lime+15% RHA

    1.15

    1.2

    1.25

    1.3

    0 10 20 30 40 50

    Water Content (%)

    Dry

    den

    sit

    y(g

    m/c

    c)

    Fig 7.7(k)

  • 60

    Soil+9% Lime+20% RHA

    1.121.141.161.181.2

    1.221.241.261.28

    0 10 20 30 40 50

    Water Content (%)

    Dry

    den

    sit

    y(g

    m/c

    c)

    Fig 7.7(l)

    Soil+12% Lime+5% RHA

    1.2

    1.25

    1.3

    1.35

    1.4

    0 10 20 30 40

    Water Content(%)

    Dry

    den

    sit

    y(g

    m/.cc)

    Fig 7.7(m)

    Soil+12% Lime+10% RHA

    1.2

    1.22

    1.24

    1.26

    1.28

    1.3

    1.32

    1.34

    0 10 20 30 40

    Water Content (%)

    Dry

    dfe

    nsit

    y(g

    m/c

    c)

    Fig 7.7(n)

  • 61

    Soil+12% Lime+15% RHA

    1.16

    1.18

    1.2

    1.22

    1.24

    1.26

    1.28

    1.3

    0 10 20 30 40

    Water Content (%)

    Dry

    den

    sit

    y(g

    m/c

    c)

    Fig 7.7(o)

    Soil+12% Lime+20% RHA

    1.14

    1.16

    1.18

    1.2

    1.22

    1.24

    1.26

    0 10 20 30 40 50

    Water Content (%)

    Dry

    den

    sit

    y(g

    m/c

    c)

    Fig 7.7(p)

    Soil+15% Lime+5% RHA

    1.221.241.261.281.3

    1.321.341.361.38

    0 10 20 30 40

    Water Content (%)

    Dry

    den

    sit

    y(g

    m/c

    c)

    Fig7.7(q)

  • 62

    Soil+15% Lime+10% RHA

    1.15

    1.2

    1.25

    1.3

    1.35

    0 10 20 30 40

    Water Content (%)

    Dry

    den

    sit

    y(g

    m/c

    c)

    Fig 7.7(r)

    Soil+15% Lime+15% RHA

    1.16

    1.18

    1.2

    1.22

    1.24

    1.26

    1.28

    0 10 20 30 40

    Water Content (%)

    DR

    Y D

    EN

    SIT

    Y(g

    m/c

    c)

    Fig 7.7(s)

    Soil+15% Lime+20% RHA

    1.11.121.141.161.181.2

    1.221.24

    0 10 20 30 40

    Water Content (%)

    Dry

    den

    sit

    y(g

    m/c

    c)

    Fig7.7 (t)

  • 63

    7.4.5 Compaction Characteristics of soil with varying percentage of RRH have been

    presented in this section in table 6.10 along with necessary graphical representation.

    Table- 7.10- Compaction characteristics of soil with varying percentage of Raw Rice

    Husk

    Sl. No % of RRH OMC(%) MDD(gm/cc)

    1 0 20 1.61

    2 2 23.2 1.47

    3 3 24.3 1.43

    4 4 25.3 1.38

    5 5 26.5 1.34

    6 6 28 1.31

    Soil+2% RRH

    1.36

    1.38

    1.4

    1.42

    1.44

    1.46

    1.48

    0 10 20 30 40

    Water Content (%)

    Dry

    den

    sit

    y(g

    m/c

    c)

    Fig 7.8(a)

  • 64

    Soil+3% RRH

    1.34

    1.36

    1.38

    1.4

    1.42

    1.44

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

    Fig 7.8 (b)

    Soil+4% RRH

    1.28

    1.3

    1.32

    1.34

    1.36

    1.38

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.8 (c)

    Soil+5% RRH

    1.221.241.261.281.3

    1.321.341.36

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

  • 65

    Fig 7.8(d)

    Soil+6% RRH

    1.18

    1.2

    1.22

    1.24

    1.26

    1.28

    1.3

    1.32

    0 10 20 30 40

    Water Content (%)

    Dry

    density9gm

    /cc)

    Fig 7.8 (e)

    7.4.6 Compaction Characteristics of soil with varying percentage of Lime and RRH have

    been presented in this section in table 6.11 along with necessary graphical representation.

    Table-7.11- Compaction characteristics of soil with varying percentage of Lime and

    RRH

    Sl. No Soil(%) Lime(%) RRH(%) OMC(%) MDD(gm/cc)

    1 100 0 0 20 1.61

    2 6 2 24 1.43

    3 6 3 25 1.4

    4 6 4 26.1 1.37

    5 6 5 27.5 1.35

    6 6 6 28.9 1.32

    7 9 2 25.1 1.4

    8 9 3 26.3 1.36

    9 9 4 27.5 1.33

    10 9 5 28.7 1.31

    11 9 6 30.3 1.29

    12 12 2 26.5 1.36

  • 66

    13 12 3 28.7 1.33

    14 12 4 29.6 1.3

    15 12 5 30.8 1.28

    16 12 6 32.2 1.25

    Soil+6% Lime+2% RRH

    1.25

    1.3

    1.35

    1.4

    1.45

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.9(a)

    Soil+6% Lime+3% RRH

    1.3

    1.32

    1.34

    1.36

    1.38

    1.4

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

    Fig 7.9(b)

  • 67

    Soil+6% Lime+4% RRH

    1.26

    1.28

    1.3

    1.32

    1.34

    1.36

    1.38

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

    Fig 7.9(c)

    Soil+6% Lime+5% RRH

    1.2

    1.25

    1.3

    1.35

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.9(d)

    Soil+6% Lime+6% RRH

    1.15

    1.2

    1.25

    1.3

    1.35

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

    Fig 7.9 (e)

  • 68

    Soil+9% Lime+2% RRH

    1.3

    1.32

    1.34

    1.36

    1.38

    1.4

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

    Fig 7.10(a)

    Soil+9% Lime+3% RRH

    1.2

    1.25

    1.3

    1.35

    1.4

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.10 (b)

    Soil+9% Lime+4% RRH

    1.221.241.261.28

    1.31.321.34

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

  • 69

    Fig 7.10(c)

    Soil +9% Lime+5% RRH

    1.1

    1.151.2

    1.251.3

    1.35

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig 7.10(d)

    Soil+9% Lime+6% RRH

    1.1

    1.15

    1.2

    1.25

    1.3

    0 10 20 30 40

    Water Content (%)

    Dry

    de

    nsity(g

    m/c

    c)

    Fig7.10 (e)

    Soil+12% Lime+2% RRH

    1.15

    1.2

    1.25

    1.3

    1.35

    1.4

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

    Fig 7.11(a)

  • 70

    Soil+12% Lime+3% RRH

    1.15

    1.2

    1.25

    1.3

    1.35

    0 10 20 30 40

    Water5 Content (%)

    Dry

    density(g

    m/c

    c)

    Fig 7.11(b)

    Soil+12% Lime+4% RRH

    1.1

    1.15

    1.2

    1.25

    1.3

    1.35

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

    Fig 7.11(c)

    Soil+12% Lime+5% RRH

    1.1

    1.15

    1.2

    1.25

    1.3

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

    Fig 7.11(d)

  • 71

    Soil+12% Lime+6% RRH

    1

    1.05

    1.1

    1.15

    1.2

    1.25

    1.3

    0 10 20 30 40

    Water Content (%)

    Dry

    density(g

    m/c

    c)

    Fig 7.11(e)

    Variation of O.M.C. with Lime content

    0

    5

    10

    15

    20

    25

    30

    0 5 10 15 20

    % of Lime

    O.M

    .C(%

    )

    O.M.C(%)

    Fig 7.12(a)

  • 72

    Variation of M.D.D.(gm/cc) with Lime

    content

    1.4

    1.45

    1.5

    1.55

    1.6

    1.65

    0 10 20

    % of Lime

    M.D

    .D.(

    gm

    /cc)

    M.D.D.(gm/cc)

    Fig 7.12(b)

    Variation of O.M.C with RHA content

    0

    5

    10

    15

    20

    25

    30

    35

    0 10 20 30

    % of RHA

    O.M

    .C.(

    %)

    O.M.C

    Fig 7.12(c)

  • 73

    Variation of M.D.D.(gm/cc) with RHA content

    0

    0.5

    1

    1.5

    2

    0 5 10 15 20 25

    % of RHA

    M.D

    .D.(

    gm

    /cc)

    M.D.D.(gm/cc)

    Fig 7.12(d)

    Variation of OMC for Lime RHA mixed soil with

    Lime

    0

    5

    10

    15

    20

    25

    30

    35

    40

    0 5 10 15 20

    % of Lime

    OM

    C(%

    ) OMC for RHA 5%

    OMC for RHA10%

    OMC for RHA15%

    OMC for RHA20%

    Fig7 .12(e)

  • 74

    Variation of MDD for Lime RHA mixed soil with

    Lime

    1.2

    1.25

    1.3

    1.35

    1.4

    1.45

    0 5 10 15 20

    %of Lime

    MD

    D(g

    m/c

    c)

    MDD for RHA 5%

    MDD for RHA 10 %

    MDD for RHA 20%

    "MDD for RHA 15%"

    Fig 7.12(f)

    Variation of OMC(%) WITH RRH content

    0

    5

    10

    15

    20

    25

    30

    0 2 4 6 8

    % of RRH

    OM

    C(%

    )

    OMC(%)

    Fig 7.12(g)

  • 75

    Variation of MDD(gm/cc) with RRH content

    0

    0.5

    1

    1.5

    2

    0 2 4 6 8

    % of RRH

    MD

    D(K

    N/m

    3)

    MDD(KN/m3)

    Fig 7.12(h)

    7.5 Strength characteristics of soil

    The strength characteristics (CBR and UCS) of both stabilized and unstabilized soil have

    been presented in this section.

    7.4.6.1 Strength characteristics of mixed soil with varying percentage of Lime have been

    presented in this section with graphical representations.

    Table -7.11 Strength Characteristics of soil with varying percent of lime

    Sl No % of

    Lime

    CBR(%),

    (compacted at

    OMC+5% moisture

    content)

    CBR(%) after 7

    days

    curing(compacted

    at OMC + 5%

    moisture content)

    UCS(KN/m2 ),

    (Specimens compacted

    at OMC+5%)

    Unsoaked Soaked Unsoaked Soaked 0day

    curing

    7 days

    curing

    28

    days

    curing

    1 0 4.3 2.6 130

    2 3 6.8 11.6 135 210 226

  • 76

    3 6 8.93 12.9 155 222 235

    4 9 10.12 13.65 12.8 14.3 170 234 248

    5 12 11.9 15.2 14.5 16 182 230 255

    6 15 12.75 17.3 190 251 276

  • 77

  • 78

  • 79

  • 80

  • 81

  • 82

  • 83

    SOIL+6% LIME+10% RHA

    0

    100

    200

    300

    400

    500

    600

    0 2 4 6 8 10 12

    PENETRATION(mm)

    LO

    AD

    (kg)

    UNSOAKED

    SOAKED

  • 84

  • 85

  • 86

  • 87

  • 88

  • 89

  • 90

  • 91

  • 92

    UCS(SOIL+6% LIME)

    0

    50

    100

    150

    200

    250

    0 0.05 0.1 0.15 0.2 0.25

    STRAIN(%)

    ST

    RE

    SS

    (kg

    /cm

    2)

    0-DAYS

    7-DAYS

    28-DAYS

  • 93

  • 94

    UCS(SOIL+10% RHA)

    0

    50

    100

    150

    200

    250

    0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1

    STRAIN(%)

    STR

    ESS

    (kg/c

    M2)

    0-DAYS

    7-DAYS

    28-DAYS

  • 95

  • 96

  • 97

  • 98

  • 99

  • 100

  • 101

  • 102

  • 103

  • 104

  • 105

  • 106

  • 107

  • 108

  • 109

  • 110

  • 111

  • 112

  • 113

  • 114

  • 115

  • 116

    Variation of CBR with Lime content

    at moisture content equal to OMC +

    5%

    0

    5

    10

    15

    20

    0 10 20

    % of Lime

    CB

    R(%

    )Unsoaked

    C.B.R(%)

    Soaked

    C.B.R.(%)

    Fig 7.13(a)

    Variation of UCS with varying % of Lime

    content compacted at moisture content

    OMC + 5%

    0

    50

    100

    150

    200

    250

    300

    0 5 10 15 20

    % of Lime

    UC

    S(K

    N/m

    2)

    UCS(Kpa) 0

    day curing

    UCS(Kpa) 7

    days curing

    UCS(Kpa) 28

    days curing)

    Fig 7.13(b)

    7.4.6.2 Strength characteristics of mixed soil with varying percentage of RHA have been

    presented in table 6.12 with graphical representation.

  • 117

    Table 7.12-Strength Characteristics of soil with varying percentage of RHA

    Sl No % of

    RHA

    CBR(%)(compacted

    at OMC+5%

    moisture content

    CBR(%) after 7

    days curing

    (compacted at

    OMC+5% moisture

    content

    UCS(KN/m2 )

    (Specimens compacted

    at OMC+5%)

    Unsoaked Soaked Unsoaked Soaked 0day

    curing

    7 days

    curing

    28

    days

    curing

    1 0 4.3 2.6 130

    2 5 7.35 4.8 93 175 212

    3 10 7.9 6.2 11.2 8.6 99 166 195

    4 15 8.2 7.9 12.25 10.3 125 235 185

    5 20 8.8 10.6 143 220 168

    Variation of CBR with varying % of RHA content

    (compacted at moisture content OMC+5%)

    0

    2

    4

    6

    8

    10

    12

    0 10 20 30

    % of RHA

    CB

    R(%

    )

    Unsoaked CBR(%)

    Soaked CBR(%)

    Fig 7.14(a)

  • 118

    Variation of UCS with varying % of RHA

    content(compacted at moisture content OMC+5%)

    0

    50

    100

    150

    200

    250

    0 10 20 30

    % of RHA

    UC

    S(K

    N/m

    2)

    UCS(Kpa) 0 day

    curing

    UCS(Kpa) 7 days

    curing

    UCS(Kpa) 28 days

    curing

    Fig 7.14(b)

    7.4.6.3 Strength characteristics of mixed soil with varying percentage of Lime and RHA

    have been presented in table 6.13 along with graphical representation.

    Table-7.13 Strength characteristics of soil with varying percentage of Lime and

    RHA

    Sl

    N

    o

    Mix proportion(% by

    dry weight)

    CBR(%)(%)(c

    ompacted at

    OMC+5%

    moisture

    content)

    CBR(5) after

    7 days curing

    compacted at

    OMC+5%

    moisture

    content)

    UCS(KN/m2 )

    (Specimens

    compacted at OMC+5%

    Soil(

    %)

    Lime(

    %0

    RHA(

    %)

    Unsoa

    ked

    Soa

    ked

    Unsoa

    ked

    Soa

    ked

    0

    day

    curi

    ng

    7

    day

    s

    curi

    ng

    28 days

    curing

    0 0 4.3 2.6 130

    3 5 8 12.5 9.2 13.1 155 178 230

  • 119

    3 10 12.85 17 205 244 260

    3 15 12 12 13.3 14 106 116 190

    3 20 12.4 11.4

    5

    90 98 145

    6 5 9.26 15 11.2 16 158 236 332

    6 10 12.95 17.4 146 205 210

    6 15 14.4 20 16.3 19.8 110 175 196

    6 20 12.6 15.6 87 150 166

    9 5 9.8 15.4 13.2 17.2 172 164 260

    9 10 12.4 23.1

    8

    175 242 296

    9 15 11.53 20.6

    5

    14.3 22.3