STUDY OF SOIL PROPERTIES WITH SILICA FUME AS STABLIZER AND COMPARING THE SAME WITH RBI-81 AND COST ESTIMATION

VISVESVARAYA TECHNOLOGICAL UNIVERSITY Belgaum-590 014

PROJECT REPORT

On

“STUDY OF SOIL PROPERTIES WITH SILICA FUME AS STABLIZER AND COMPARING THE SAME WITH RBI-81 AND COST ESTIMATION” Submitted in partial fulfillment of the requirements for the Degree of

Post Graduate Diploma in Highway Technology by

VENU GOPAL.N USN: 1IR08CHT19 Under the Guidance of

Miss. G. KAVITHA Lecturer, RASTA – Center for Road Technology, Bangalore.

RASTA – Center for Road Technology VTU – Extension Center VOLVO Construction Equipment Road Machinery Campus Peenya, Bangalore – 560 058 1

RASTA – Center for Road Technology VTU – Extension Center VOLVO Construction Equipment Road Machinery Campus

Bangalore – 560 058.

CERTIFICATE

Certified

that

the

Project

work

entitled

“STUDY

OF

SOIL

STABLIZER

AND

PROPERTIES

WITH

SILICA

FUME

AS

COMPARING

THE

SAME

WITH

RBI-81

ESTIMATION”

AND

COST

is a bonafied work carried out by, Mr. VENU GOPAL.N,

University Seat Number 1IR08CHT19 in partial fulfillment for the award of MTech degree in Highway Technology of the Visvesvaraya Technological University,

Belgaum

during the year 2008-2009. It is certified that all

corrections/suggestions indicated for Internal Assessment have been incorporated in the report. The Project report has been approved as it satisfies the academic requirements in respect of Project work prescribed for the said Degree.

2

Signature of Guide Head of PG Studies

Signature of

(Miss. G.Kavitha)

(Dr. Krishnamurthy)

ACKNOWLEDGEMENT It’s indeed my immense pleasure to wish my deep sense of gratitude to our teaching faculty who inexorably tried to get the best out of me. It is because of their valuable guidance and continuous encouragement without which this milestone would not have been a success.

I extend my sincere thanks to Dr.Krishna Murthy, for his valuable guidance and suggestions during the course of study.

I would like to express my sincere gratitude to Miss. G.Kavitha and Mr. Anjaneyappa faculties of IR Rasta for excellent guidance and encouragement throughout the seminar.

Last but not the least, I also thankful to all my class mates, non-teaching staff and friends, who have helped directly or indirectly for the successful completion of this work.

3

SYNOPSIS Soils exhibits high plasticity characteristics, low strength properties and high swell shrink characteristics. The alternative swell- shrink seasons causes distress to the structures and the pavements constructed on them. Maintenance and repair costs of the distressed structures and pavements are quite high. It is, therefore, necessary either to bring suitable soils from far off borrow areas or to stabilize locally available soils to improve their engineering properties. In the present study, a soil sample was subjected to laboratory investigation to know the grain size distribution pattern and to determine liquid limit, plastic limit and plasticity index, optimum moisture content, maximum dry density and California bearing ratio values. The laboratory investigations indicate the soil samples posses’ low strength. In order to improve the strength of native soil, the soil samples were treated by varying Silica Fume and RBI-81 grade content in the range of 1% to 4% by weight. The treated soil samples were subjected to triaxial compression test to determine strength of soil. The above obtained values such as CBR value, young’s Modulus etc were used for the design of pavement based on IRC methods, thickness of pavement were calculated and compared. This involves replacing of base and sub-base course with stabilized locally available soil, and comparing same with different stabilizer (RBI-81and Silica Fume). To evaluate the difference in cost.

4

INDEX Topics

Page No

Chapter.1 Introduction

4-6

1.1 General Studies

4

1.2 Desirable properties of soil

5

1.3 Objective of present study

6

1.4 Scope of Present Study

6

Chapter.2

Literature review

7-20

2.1 General Studies

7

2.2 Characteristics of soil

7

2.3 Index properties

7

2.4 Determination of Soil Properties

9

2.5 Subgrade soil Strength

9

2.6 Soil Stabilization Using Inorganic stabilizer

11

2.7 Stabilized Soil with RBI-81

12

2.8 Silica Fume

15

2.9 Chemical Properties of silica fume

17

2.10 Physical properties and contribution

17

2.11 Soil Stabilization method

19

2.12 Technique of Stabilization

20 5

2.13 Design and Cost estimation

20

Chapter.3 Present Investigation

21-25

3.1 General Studies

22

3.2 laboratory test conducted

22

Chapter.4 Analysis of Result

26-43

4.1 General Studies

26

4.2 Laboratory test result

26

4.3 Design of Pavement

36

4.4 Materials Quantity

39

4.5 Cost Estimation

40

Chapter.5 Discussion and conclusion

44-45

5.1 Discussion

44

5.2 Conclusion

45

5.3 Scope for future studies

45

References

46

Annexure 1

47-57

6

CHAPTER-1 INTRODUCTION 1.1

GENERAL Soil - mineral matter formed by the disintegration of rocks due to action of water, frost,

temperature, pressure or by plant or animal life. Soil is the most abundantly available construction material; the term soil has different connotations for scientists belonging to different disciplines. The definition given to a soil by an agriculturist or a geologist is different from the one used by a civil engineer. For a civil engineer, soils mean all naturally occurring, relatively unconsolidated earth material- organic or inorganic in character that lies above the bed rock. Soils can be broken down into their constituent particles relatively easily, such as by agitation in water.

Soil is the ultimate foundation material which supports the overlying structure. The proper functioning of the above lying structure will therefore depend critically on the success of the foundation element. Soil is the cheapest and the most widely used material in a highway system, either in its natural form or in a processed form. All road pavement structures eventually rest on soil foundation. However, soil is highly heterogeneous and anisotropic in nature and occurs in unlimited varieties, with widely different engineering properties. Considering all these aspects, a through study of the engineering properties of soil is of vital importance in working out an appropriate design of the pavement structure which will yield an acceptable level of performance of the road over the design life under the given traffic and climatic conditions. In any road embankment, the bulk of the material used is soil and if properly designed, should possess stable slopes and should not settle to any appreciable extent. Also, the embankments require a stable 7

foundation; if the foundation soil happens to be soft clay, unless properly designed; excessive settlement or even ultimate failure can take place. In developing countries like India the biggest handicap to provide a complete net work of road system is the limited finances available to build road by the conventional methods. Therefore there is a need to resort to one of the suitable methods of low cost road construction to meet the growing needs of the road traffic. The construction cost can be considerably decreased by selecting local materials including local soils for the construction of the lower layers of the pavement such as the sub-base course. If the stability of the local soil is not adequate for supporting wheel loads, the properties are improved by soil stabilization techniques. Thus the principle of soil stabilized road construction involves the effective utilization of local soils and other suitable stabilizing agents.

Earthwork as an important part of road construction In any highway engineering work the construction of the embankment or the sub grade is a very important activity. The earthwork constitutes 30% of the cost of the road project. The pavement directly rests on the artificially prepared soil sub grade and thus derives considerable strength from it. The adequate design and construction of embankments is therefore the key to the successful performance of the roads.

1. 2 Desirable properties of

Sub grade

soil

➢ Stability

➢ Incompressibility ➢ Permanency of strength ➢ Minimum changes in volume and stability under adverse condition ➢ Good drainage ➢ Ease of compaction

The soil should possess adequate stability or resistance to permanent deformation under loads and should possess resistance retaining

to weathering thus

the desired subgrade support. Minimum variation

minimum variation

in differential expansion and

d

ifferential

in volume will ensure strength values.

drainage is essential to avoid excessive moisture retention and to reduce the 8

Good

potential frost action. Ease of compaction ensures higher dry density and strength particular type and amount of compaction

under

(1)

1.3 Objective of present study •

To characterize the soil

•

To classify the soil as per IRC Classification .

•

To compare the OMC of the given soil Proctor compaction tests

under investigation based on its index properties

.

& to achi eve Maximum Dry density by

.

•

To determine the strength of soil by Triaxial method .

•

To study the effect of RBI -81 and Silica F ume on soil by varying percentage

•

To determine the strength enhancement of the given soil with stabiliz

.

er.

• To determine the thickness by conventional method and Annexure method. • To compare the variation in cost by above method.

1.4 Scope of present study The present study deals with the testi following tests were

ng of soil properties of soil sample

done on the soil:

 Grain size analysis 

Atterberg limits

 Compaction  California bearing ratio 

Triaxial test 9

. The

The soil is stabilized with a commercially available stabilizer called Road Building International -81 (RBI-81) and the strength enhancement of the soil is studied. And also compared with replacing RBI-81 with Silica fume, strength enhancement is studied. Economically low cost design studies are done.

CHAPTER-2 LITERATURE REVIEW 2.1

General Subgrade soil is an integral part of the road pavement structure as it provides

the support to the pavement from beneath. The main function of the subgrade is to give adequate support to the pavement and for this the subgrade should posses’ sufficient stability under adverse climatic and loading conditions .The formation of waves, corrugations, rutting and shoving in black top pavements and the phenomenon of pumping, blowing and consequent cracking of cement concrete pavements are generally attributed due to the poor subgrade conditions. When soil is used in embankment construction, in addition to stability incompressibility is also important as differential settlement may cause failures. Compacted soil and stabilized soil are often used in sub – base or base course of highway pavements. The soil is therefore considered as one of the principle highway materials. (1)

2.2 Characteristics of soil Soil consists mainly of mineral matter formed by the disintegration of rocks, by the action of water, frost, temperature, pressure or by plant or animal life. Based on the individual grain size of soil particles, soils have been classified as gravel, sand, silt and clay. The characteristics of soil grains depend on the size, shape, surface texture, chemical composition and electrical surface charges. Moisture and dry density influence the engineering behavior of a soil mass. (1,2,3)

2.3 Index properties of soil 10

The wide range of soil types available as highway construction materials have made it obligatory on the part of the highway engineer to identify and classify the different soils. The soil properties on which their identification and classification are based on are known as index properties. The index properties which are generally used are grain size distribution, liquid limit, plastic limit and plasticity index. (1,2,3)

Grain size analysis The grain size distribution is found by mechanical analysis. The components of soils which are coarse grained may be analyzed by sieve analysis and the soil fines by sedimentation analysis. The grain size analysis or the mechanical analysis is hence carried out to determine the percentage of individual grain size present in a soil sample. (1,2,3)

Consistency limits and indices The physical properties of fine grained soils, especially of clays differ very much at different water contents. Clay may be almost in a liquid state, or it may show plastic behavior or may be stiff depending on the moisture content. Plasticity is a property of outstanding importance for clayey soils, which may be explained as ability to undergo changes of shape without rupture. Atterberg in 1911 proposed a series of tests, mostly empirical, for the determination of the consistency and plastic properties of fine soils. These are known as Atterberg limits and indices. Liquid limit may be defined as the minimum water content at which the soil will flow under the application of very small shearing force. It is determined usually in the laboratory using a mechanical device. Plastic limit may be defined as the minimum moisture content at which the soil remains in a plastic state. The lower limit is arbitrarily defined and determined in the laboratory by a prescribed test procedure. Plasticity index is defined as the numerical difference between the liquid and the plastic limits. Plasticity index thus indicates the range of moisture content over which the soil is in plastic condition.(1,2,3)

11

2.4 Determination of soil properties There are various tests that are carried out to determine the various properties of the soil 1. Liquid limit: The water content at which the soil has a small shear that it flows to close a

groove of standard width when jarred in a specified manner. 2. Plastic limit: The plastic limit is the water content at which the soil to crumble when rolled

into threads of specified size. 3. Plasticity index: The amount of water which must be added to change a soil from its

plastic limit to its liquid limit is an indication of the plasticity of the soil. The plasticity is measured by the “plasticity index” which is equal to the liquid limit minus the plastic limit. (5)

4. Grain size analysis: It is also known as mechanical analysis of soils is the determination of

the percentage of individual grain sizes present in the sample. The results of the test are of great value in soil classification. There are two methods of sieve analysis : (i)

wet sieving applicable to all soils and

(ii)

Dry sieving applicable to soils having negligible proportion of clay and silt. (3)

1. Compaction test: This test is carried out to find out the optimum moisture content and the

maximum dry density of the given soil(2,3).

2.5 Sub-grade soil strength The factors on which the strength characteristics of soil depend are: (i)

Soil type

(ii)

Moisture content

(iii)

Dry density 12

(iv)

Internal structure of the soil and

(v)

The type and mode of stress application (1).

2.5.1 Evaluation of soil strength The tests used to evaluate the strength properties of soils may be broadly divided into three groups: (i)

Shear test

(ii)

Bearing test and

(iii)

Penetration test. The following tests were carried out in the present study to find the strength of the soil

1. CBR test: This test was developed by the Californian Division of highways as a method of classifying and evaluating soil sub-grade and base course materials for flexible pavement. The CBR is a measure of resistance of a material to penetration of standard plunger under controlled density and moisture conditions. 2. Triaxial compression test: This test is carried to evaluate the in-situ

strength of the soil

sample under controlled loading.(2,3,)

Table: Density requirement of embankment and subgrade Type of work

Maximum laboratory dry unit weight when tested as per IS:2720(part 8)

Embankments up to 3 meters Height, not subjected to expensive flooding. Not less than 15.2kN/cu.m. Embankments exceeding 3 meters height or embankments of any height subject to longNot less than 16.0kN/cu.m. periods of inundation Subgrade and earthen Shoulders/ verges/ backfill

Not less than 17.5kN/cu.m.

13

2.6 Soil stabilization using powder based inorganic stabilizer The effectiveness of this stabilizer both plastic & non-plastic soils is studied by carrying out a detailed laboratory study. Different types of soils that is gravelly, sandy, silty, clayey are stabilized with inorganic stabilizer in the range of 2-12%. Apart from the study of geotechnical properties of individual soils, strength in terms of UU & CBR of stabilized soils was evaluated. •

The selected soils viz. gravelly, sandy & silty are observed to be non-plastic. Clayey soil is observed to be highly compressible in nature.

•

The Triaxial strength of all the soils increases with the addition of stabilizer content for different curing periods. The rate of increase is more in silty & gravelly soils as compared to sandy & clayey soils.

•

The CBR value increases with stabilizer content for all soils. It is observed that the value increases significantly after addition of 2% content. The rate of increase is more in gravelly & silty soils as compared to sandy & clayey soils.

•

Gravelly soil with 6% & silty soil with 4% stabilizer content may be used as a sub-base layer of pavement. Gravelly & silty soils with 8% stabilizer content may be used as a base layer of pavement.

•

All the soils stabilized with 2% stabilizer content may be used for shoulder construction.

•

It can be concluded that powder based inorganic stabilizer has the potential for stabilization of gravelly & silty soils to make it suitable for its use in improved sub base/base layer/shoulder construction of a road pavement. Solution to a typical practical problem indicated substantial reduction in the total pavement thickness which not only reduces the total cost but also avoids the use of natural depleting conventional materials. Test tracks of suitable length may be constructed & monitored over a period of time before adopting such specifications for large scale field applications.

14

2.7 Stabilized road If the stability of the local soil is not adequate for supporting the wheel loads, the properties are improved by soil-stabilization techniques. Thus the principle of soil stabilized road construction involves the effective utilization of local soils and other suitable stabilizing agents. The term soil stabilization means the improvement of the stability or bearing power of the soil by the use of controlled compaction, proportioning and or the addition of suitable admixture or stabilizers. Soil stabilization deals with physical physico-chemical and chemical methods to make the stabilized soil serve its purpose as a pavement component material. (1,4)

2.7.1 Advantages of stabilization (i)

It improves the engineering properties of poor soils as well as enhancing that of good soils to meet the specified requirements.

(ii)

It helps reduce the need of existing borrow pit materials and prospecting of new borrow pit sources there by protecting environment.

(iii)

It eliminates the need for the landfill sites for dumping of poor materials and environmental harmful materials as well as construction waste

(iv)

It allows faster construction because removal of substandard material and transportation of good materials is not required.

(v)

Time saved also adds to cost saving of the project and allows more projects to be undertaken and complete within the same time frame.

2.7.2 Properties of stabilization •

Bonds soil particles together (increases strength & stiffness).

•

Reduces permeability (fills voids, forms membrane).

•

Improves compaction (lubrication, particle restructuring).

2.7.3 Features & Benefits 15

•

Higher resistance (R) values

•

Reduction in plasticity

•

Lower permeability

•

Reduction of pavement thickness

•

Elimination of excavation, material hauling and handling, and base importation

•

Aids compaction

•

Provides "all-weather” access onto and within project sites.

The principles are: •

Evaluating the properties of given soil

•

Deciding the method of supplementing the lacking property by the effective and economical method of stabilization.

•

Designing the stabilized soil mix for intended stability and durability values. RBI Grade 81 soil stabilizer is an advanced technological development with economic and

environmental benefits. It is a unique, environmentally friendly, comprehensive and irreversible inorganic stabilizer for road construction. The technology was developed by scientists incorporating natural materials with well proven efficacy and durability. It has undergone a rigorous development and verification process internationally coordinated by Road Building International and has been granted an international patent. Road Building International has engineered an inorganic product: •

is extremely effective

•

whose action is irreversible

•

is produced from natural ingredients

•

is capable of providing rapid infrastructure development progress while preserving the environment by using the in-situ natural soil.

•

Avoids the environmental burdens associated with conventional road construction.

RBI Grade 81 can be effectively applied to all soil types: • In-situ application with RBI Grade 81 causes no interruption to traffic. • Resultant cost savings of 60% (in comparison to conventional methods). • RBI Grade 81 avoids the otherwise necessary removal and dumping of asphalt (5). 16

2.7.4 Properties of RBI-81 stabilizer Table 2.1: properties of RBI-81 stabilizer (5) CHEMICAL COMPOSITION POWDER Properties

% by mass

Ca

CaO- 52-56

Si

SiO215-19

S

SO3 9-11

Al

Al2O3 5-7

Fe

Fe2O3 0-2

Mg

MgO 0-1

Mn, K, Cu, Zn

Mn+K+Cu+Zn 0,1-0,3

H2o

1-3

Fibers (polypropylene)

0-1

Additives

0-4

2.8 Silica fume 2.8.1 Definition for silica fume The American Concrete Institute (ACI) defines silica fume as “very fine nonCrystalline silica produced in electric arc furnaces as a by-product of the production of elemental silicon or alloys containing silicon” (ACI 116R). It is usually a gray colored powder, somewhat similar to Portland cement or some fly ashes(6,7).

17

2.8.2 Pozzolanic — will not gain strength when mixed with water. Examples include silica fume meeting the requirements of ASTM C 1240, Standard Specification for Silica Fume Used in Cementitious Mixtures, and low-calcium fly ash meeting the requirements of ASTM C 618, Standard Specification for Coal Ash and Raw or Calcined Natural Pozzolanic for Use in Concrete, Class F.

2.8.3 Cementitious — will gain strength when mixed with water. Examples include ground granulated blast-furnace slag meeting the requirements of ASTMC989, Standard Specification for Ground Granulated Blast-Furnace Slag for use

Concrete and Mortars, or high-calcium fly

ash meeting the requirements of ASTM C 618, Class C.

2.8.4 Production Silica fume is a by-product of producing silicon metal or ferrosilicon alloys in smelters using electric arc furnaces. These metals are used in many industrial applications to include aluminum and steel production, computer chip fabrication, and production of silicones, which are widely used in lubricants and sealants. While these are very valuable materials, the byproduct silica fume is of more importance to the concrete industry(7).

SilicaFum eP Fig shows production of Silica 18

Fig 1.2 EMISSION OF SILICA FUME Figure 1.2 shows a smelter in the days before silica fume was being captured for use in concrete and other applications. The “smoke” leaving the plant is actually silica fume. Today in the United States, no silica fume is allowed to escape to the atmosphere. The silica fume is collected in very large filters in the bag house and then made available for use in concrete

2.9 Chemical Properties Amorphous. This term simply means that silica fume is not a crystalline material. A crystalline material will not dissolve in concrete, which must occur before the material can react. Don’t forget that there is a crystalline material in concrete that is chemically similar to silica fume. That material is sand. While sand is essentially silicon dioxide (SiO2), it does not react because of its crystalline nature. Trace elements. There may be additional materials in the silica fume based upon the metal being produced in the smelter from which the fume was recovered. Usually, these materials have no impact on the performance of silica fume in concrete.

2.10 Physical Properties 19

Particle size. Silica fume particles are extremely small, with more than 95% of the particles being less than 1 µm (one micrometer). Particle size is extremely important for both the physical and chemical contributions (discussed below) of silica fume in concrete. Bulk density. This is just another term for unit weight. The bulk density of the asproduced fume depends upon the metal being made in the furnace and upon how the furnace is operated. Because the bulk density of the as-produced silica fume is usually very low, it is not very economical to transport it for long distances. Specific gravity. Specific gravity is a relative number that tells how silica fume compares to water, which has a specific gravity of 1.00. Silica fume has a specific gravity of about 2.2, which is somewhat lighter than portland cement, which has a specific gravity of 3.15.

PHYSICAL PORPERTIES OF SILICA FUME(7)

Specific surface.

20

Specific surface is the total surface area of a given mass of a material. Because the particles of silica fume are very small, the surface area is very large. We know that water demand increases for sand as the particles become smaller; the same happens for silica fume. This fact is why it is necessary to use silica fume in combination with a water-reducing admixture or a super plasticizer. A specialized test called the “BET method” or “nitrogen adsorption method” must be used to measure the specific surface of silica fume. Specific surface determinations based on sieve analysis or air-permeability testing are meaningless for silica fume.

Figure 2.1 Figure2.1. Photomicrograph of Portland cement grains (left) and silica-fume particles (right) at the same magnification. The longer white bar in the silica fume side is 1 micrometer long. Note that ACI 234R, Guide for the Use of Silica Fume in Concrete, estimates that for a 15 percent silica-fume replacement of cement, there are approximately 2,000,000 particles of silica fume for each grain of Portland cement.

Chemical contributions Because of its very high amorphous silicon dioxide content, silica fume is a very reactive pozzolanic material in concrete. As the Portland cement in concrete begins to react chemically, it releases calcium hydroxide. The silica fume reacts with this calcium hydroxide to form additional binder material called calcium silicate hydrate, which is very similar to the calcium silicate hydrate formed from the portland cement.

Physical contributions 21

Adding silica fume brings millions and millions of very small particles to a concrete mixture. Just like fine aggregate fills in the spaces between coarse aggregate particles, silica fume fills in the spaces between cement grains. This phenomenon is frequently referred to as particle packing or micro-filling. Even if silica fume did not react chemically, the micro-filler effect would bring about significant improvements in the nature of the concrete. Below table present a comparison of the size of silica-fume particles to other concrete ingredients to help understand how small these particles actually are.

2.11 Soil stabilization methods The methods of soil stabilization which are in common use are: (i)

Chemical Stabilization

(ii)

Mechanical stabilization(1)

2.11.1 Effects of stabilization Soil stabilization may result in any one or more of the following changes: 1. Increase in stability, change in properties like density or swelling, change in physical characteristics. 2. Change in chemical properties. 3. Retaining and desired strength by water proofing(1)

2.12 Techniques of soil stabilization Based on the above principles, the various technique of soil stabilization may be grouped Proportioning technique 1. Cementing agents 2. Modifying agents 3. Water proofing agents 4. Water repelling agents 22

5. Water retaining agents 6. Heat treatment 7. Chemical stabilization 8. In all the above methods, adequate compaction of the stabilized layers is the most

essential requirement. (1)

2.13 Design and cost estimation. As per IRC-37 the conventional methods was used to calculate the thickness of different layer, which was further compared with IRC-37 Annexure method difference in thickness is calculated. (8) The cost which are involved for materials were taken from Schedule Rate (SR), and calculated. (9)

CHAPTER-3 PRESENT INVESTIGATION 3.1 General Studies: Soil is one of the principle materials of construction in soil embankments and in stabilized soil base and sub-base courses. Various types of soil have various properties at different stretch of the sub grade. Thus, it is important to carry out basic soil tests at a stretch of 300mts. In view of the wide diversity in soil type, it is desirable to classify the

subgrade soil

into groups possessing similar physical properties. In the present investigation the soil is classified on the basis of simple laboratory tests such as grain size analysis and consistency limit tests. Soil compaction is an important phenomenon in highway construction as compacted 23

subgrade improves the load supporting ability of the pavement; in turn resulting in pavement thickness requirement. Compaction of earth embankments would result in decreased settlement. Thus the behavior of soil

subgrade material could be considerably improved by

adequate compaction under controlled conditions. The laboratory compaction tests are conducted and the optimum moisture content at which the soil should be compacted and the dry density that should be achieved at the construction site has been determined. Soil for the present study was obtained f rom the project site . The basic tests like Atterberg limits, compaction test, California bearing res istance & Triaxial test was done to characterize the soil based on its properties. The representative

soils were stabilized using the stabilizers Road Building

International -81 and Silica Fume for different proportions i.e. 1%, 2% and 4 % stabilizer to assess their properties and the results were analyzed

. Road Building International has

engineered as an inorganic product:

• Is capable of providing rapi d infrastructure development

progress while preserving

the environment by using the in-situ natural soil. • Avoids the environmental burdens associated with conventional road construction the present study, soil was subjected to basic tests like: • Grain size analysis • Atterberg limits • Compaction • California bearing ratio test • Triaxial test (at 0.7, 1.4 and 2.1 kg/ sqcm confinement)

3.2 Laboratory test conducted on soil: (2,3) 3.2.1 Grain size analysis:

24

. In

The percentage of various sizes of particle in a given dry soil sample is determined by grain size analysis. Grain size analysis also knows as mechanical analysis of soils is the determination of the percent of individual grain sizes present in the sample.

Fig 1: Indian standard grain size soil classification system

Fig-3.1 Sieve Analysis Apparatus

3.2.2 Atterberg limits: By consistency is meant the relative ease with which soil can be deformed. This 25

term is mostly used for fine grained soils for which the consistency is related to a large extent to water content. Consistency denotes degree of firmness of the soil which may be termed as soft, firm, stiff or hard. In 1911

Atterberg divided the entire range from liquid to

solid state into four stages liquid state, plastic state, semi -solid state and solid state. He set arbitrary limits known as consistency limits or

Atterberg limits, for these divisions in

terms of water content. Thus the consistency limits are the water contents at which the soil mass passes from one state to the next. Liquid limit (W I): It is defined as the minimum water content at which the soil is still in the liquid state, but has a small shearing strength against flowing which can be measured by standard available means. With reference to the standard liquid limit device, it is defined as the minimum water content at which a part of soil cut by a groove of standard

dimensions will flow together for a distance of 12mm under an

impact of 25

blows in the device. Plastic limit (W P): plastic limit is the water content corresponding to an arbitrary limit between the plastic and the semi-solid states of consistency of a soil. It is defined as the minimum water content at which a soil will just begin to crumble when rolled into a thread approximately

3mm in dia.

3.2.3 Compaction test: Compaction of soil is a process by which the soil particles are constrained to be packed more closely together by reducing the air voids. It causes decrease in air voids and consequently increases in dry density. This may result in increase in shearing strength. Degree of compaction is usually measured quantitatively by dry density. Compaction refers to a more or less rapid reduction mainly in the air voids under a loading of short duration Increase in dry density of soil due to compaction mainly depends on two factors. •

Compacting moisture content

•

The amount of compaction.

3.2.4 California bearing ratio test (CBR): The CBR is a measure of resistance of a material to penetration of standard plunger under controlled density and moisture conditions. CBR test is mainly utilized for 26

the design of pavement structure. The test is simple and has been extensively investigated for field correlations of flexible pavement thickness requirement. The test consists of causing a cylindrical plunger of 50mm diameter to penetrate a pavement component m

aterial a 1.25mm/min. The load

for 2.5mm and

5mm

recorded. This load is expressed as a percentage of standard load value at a respective deformation level to obtain CBR value.

27

are

Fig-3.2 CBR mould preparation

3.2.5 Triaxial compression

Fig 3.3- CBR Testing Machine

test :

The triaxial compression test in applying all the three principal stress

which the test specimen is compressed by

. The cell pressure in the 28

triaxial cell is also called

the confining pressure.

Fig-3.4 Triaxial testing machine

Fig-4.5

CHAPTER-4 ANALYSIS OF RESULTS 4.1 General

29

Mould Extractor

The laboratory tests for the various properties of the soil were conducted and the results thus obtained are tabulated and analyzed. The test was conducted on locally available soil and the properties were compared with and without the use of stabilizer. 4.2

Laboratory tests on soil material

4.2.1 Wet sieve analysis Sample Calculation: Sample: Native Red Soil Wt of sample taken: 500gms Table 4.1

shows the sample calculation

sample

Red Soil

sieve size

Wt of sample reained

cumulative Wt retained

cum % wt ret

%fine passing

4.75

122.17

122.17

24.434

75.566

2.36

24.44

146.61

29.322

70.678

1.18

41.22

187.83

37.566

62.434

0.6

40.65

228.48

45.696

54.304

0.425

29.94

258.42

51.684

48.316

0.15

36

294.42

58.884

41.116

304.01

60.802

39.198

0.075 Gravel Sand

9.59 Fines

24.434

24.434

24.434

Graph of wet sieve analysis Type of soil as per IS-Classification: Sandy Clayey (SC) Soil

4.2.2 Atterberg limit: Native Red Soil Cu=23.54 30

Cc=3.1

Table 4.2

shows the liquid limit calculation

No of blows 10 13 24 29

M/C % 45.94 44.08 42.58 41.72

Table 4.2.1 shows Plastic limit M/C container No

123

75

52

21

Wt of container gms (W1) Wt of cont + wit soil (W2) Wt of cont + dry soil % (W3)

23.86 26.03

21.98 23.58

27.18 29.15

40.47 42.34

25.54

23.23

28.71

41.92

M/c %

29.17

28.00

28.76

28.97

28.72 Remarks LL

"from graph" PL PI

42.4 28.72 13.68

Liquid limit and Plastic Index table

LL

Native(R S) 42.4

RS+1% RBI 42

RS+2% RBI 41.61

RS+4% RBI 40.01

RS+1% SF 40

RS+2% SF 39.57

PL

28.72

28.74

28.76

27.92

26.97

27.51

26.93

PI

13.68

13.24

12.87

12.09

13.03

12.06

11.63

soil

4.2.3 Compaction test Sample Calculation: Sample: Red Soil 31

RS+4% SF 38.6

Type of Compaction

:

Modified Proctor

Type of Soil

:

New

Type of Mould

: Small

Type of Hammer

:

4.89

No. of Layers

:

5

No. of Blows

:

25 Table 4.2.2 shows the sample calculation

Moisture Content (%) 9.07 11.33 12.91 14.73 16.41

Bulk Density (g/cc) 1.90 1.96 2.11 2.12 2.08

Dry Density (g/cc) 1.74 1.76 1.86 1.85 1.79

Remarks: MDD and OMC for different % are of RBI-81 & Silica Fume. Type of Stabilizer percentage Compaction OMC (%) MDD (gm/cc)

OMC=13.54%

Native(RS ) MDD=1.877gm/ RBI-81 0%cc 1% 2% 13.54 1.877

13.48 1.882

13.52 1.887

4% 13.89 1.869

Silica fume 1% 2% 12.34 1.887

13.16 1.893

4.2.4California bearing ratio test Sample Calculation: Sample: Red Soil Area of plunger = 19.64cm2 CBR = 8% (This has been assumed as per Guidelines) (1), the value is on lower side.

32

4% 13.1 1.94

4.2.5

Triaxial Compression Test:

Sample Calculation: Red soil Specimen details: Diameter: 3.8cm Height: 7.6cm Volume, V = (πd2/4) * h = (π*3.82/4) * 7.6 V = 86.19 cm3 Mass = volume * density = 86.19 * 1.87 = 167.48gms Water = 13.54% * 161.78 = 20.07gms RBI

Silica Fume

1.0% = 1.62 gms

1.63gms

2.0% = 3.52 gms

3.26gms

4.0% = 6.44 gms

6.69gms

The above calculated mass of soil, water and RBI according to varying percentages are mixed together and put into the mould, mould is extracted and placed for moist curing for 3days. Table 4.2.5 sample calculation at different confining pressure says 0.7, 1.4 and 2.1kg/cm2. Native Red soil cm length of specimen Dia of specimen area of specimen(Ai)

pressure(σ 31) kg/cm2 Load at Failure (kg) least count (dial gauge), mm least count ( proving ring),

mm

7.6

76

3.8 11.3 4

38 1133. 90 33

2.1

0.001 0.002

mm dial gauge

0 3 4 5 7 7 12 23 47 66 89

0 0.66 0.88 1.1 1.54 1.54 2.64 5.06 10.34 14.52 19.58

0.00E+00 1.32E-04 2.63E-04 3.95E-04 5.26E-04 6.58E-04 7.89E-04 9.21E-04 1.05E-03 1.18E-03 1.32E-03

113 141 163 187

24.86 31.02 35.86 41.14

1.45E-03 1.58E-03 1.71E-03 1.84E-03

11.323 11.321 11.320 11.318

2.20 2.74 3.17 3.63

213 239 261 292

46.86 52.58 57.42 64.24

1.97E-03 2.11E-03 2.24E-03 2.37E-03

11.317 11.315 11.314 11.312

4.14 4.65 5.08 5.68

0.19 0.20 0.21 0.22 0.23 0.24

0 3 4 1 1.2 1.2 2.2 4.3 9.2 13.1 17.4 1+2. 3 8.1 12.3 17.2 2+2. 3 7.4 12.1 18.2 3+3. 4 9 14.4 4+.2 -0.1 .4

Correct ed area Ac=(Ai/ (1∈)cm2 11.339 11.338 11.336 11.335 11.333 11.332 11.330 11.329 11.327 11.326 11.324

319 345 374 402 401 398

2.50E-03 2.63E-03 2.76E-03 2.89E-03 3.03E-03 3.16E-03

11.311 11.309 11.308 11.306 11.305 11.303

6.20 6.71 7.28 7.81 7.80 7.78

250

0.25

1.3

394

3.29E-03

11.302

7.73

260

0.26 1.4

70.18 75.9 82.28 88.44 94.6 99.88 100.7 6 111.3 2

3.42E-03

11.300

proving ∆ (mm)

noted

taken

0 10 20 30 40 50 60 70 80 90 100

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10

110 120 130 140

0.11 0.12 0.13 0.14

150 160 170 180

0.15 0.16 0.17 0.18

190 200 210 220 230 240

Deviator stress (σd=F/Ac) Normal Stress (σ 11)kg/cm2

readin gs

391

load(k g)

1.294 3.394

34

Strain(∈)

Stress (kg/c m2) 0.00 0.06 0.08 0.10 0.14 0.14 0.23 0.45 0.91 1.28 1.73

7.64

Table 4.2.6 Shear Strength obtained for Native soil (RS)

σ

(Kg/cm2) 0.7 1.4 2.1

31

ShearStren gth (kg/cm2) 0.213 0.287 0.311

%Dosage

0

Annexure 1: Shows Triaxial compression test Graphs with different %dosage at 0.7, 1.4 and 2.1kg/sqcm confinement pressure. Table 4.2.7 Abstract of Triaxial Test Result. Sample sl no

Native Soil area'Ac load '

Stress (Kg/cm)

σ

σ

σ

Atterberg limits

LL

Kg

Sqcm

1

4.93

11.267

0.7

0.962

1.662

42.04

2

5.87

11.284

1.4

1.001

2.401

42.04

3

7.81

11.28

2.1

1.293

3.393

42.04

31

d

35

11

E3 value Kg/sqc PI m Mpa 238.3 13.68 2430 0 253.0 13.68 2580 1 269.7 13.68 2751 8

Sample sl no

1 2 3

Sample sl no

1 2 3

Sample sl no

1 2 3

Native Soil + 1% RBI81 area'Ac load '

Stress (Kg/cm)

σ

σ

σ

Atterberg limits

LL

Kg

Sqcm

7.59 10.3 5 11.3 3

11.289

0.7

0.437

1.137

42

11.312

1.4

0.519

1.919

42

11.29

2.1

0.692

2.792

42

31

Native Soil + 2% RBI81 Area load 'Ac' Kg 10.8 4 11.2 9 14.5 9

Sqcm

11

Stress (Kg/cm)

σ

31

σ

d

σ

Atterberg limits 11

LL

11.303

0.7

0.672

1.372

41.61

11.283

1.4

0.917

2.317

41.61

11.278

2.1

1.005

3.105

41.61

Native Soil + 4% RBI81 Area load 'Ac' Kg 14.5 8 15.4 7 20.5 8

d

Sqcm

Stress (Kg/cm)

σ

31

σ

d

σ

E3 value Kg/sqc PI m Mpa 353.0 12.87 3600 4 360.9 12.87 3681 8 392.2 12.87 4000 7

Atterberg limits 11

LL

11.29

0.7

1.291

1.991

40.01

11.293

1.4

1.370

2.770

40.01

11.278

2.1

1.825

3.925

40.01

36

E3 value Kg/sqc PI m Mpa 343.2 13.24 3500 3 355.2 13.24 3622 0 359.6 13.24 3667.67 8

E3 value Kg/sqc PI m Mpa 366.0 12.09 3733 8 401.0 12.09 4090 9 451.1 12.09 4600 1

Sampl e sl no

Native Soil + 1%Silica Fume load

Area 'Ac'

Kg

Sqcm

Stress (Kg/cm)

σ

31

σ

d

σ

Atterberg limits 11

LL

1

8.86

11.284

0.7

1.021

1.721

40.00

2

11.55

11.259

1.4

1.133

2.533

40.00

3

12.61

11.275

2.1

1.701

3.801

40.00

Sampl e sl no

Native Soil + 2%Silica Fume load

Area 'Ac'

Kg

Sqcm

Stress (Kg/cm)

σ

31

σ

d

σ

Atterberg limits 11

LL

1

11.52

11.281

0.7

0.785

1.485

39.47

2

12.76

11.294

1.4

1.023

2.423

39.47

3

19.18

11.287

2.1

1.117

3.217

39.47

Sampl e sl no

E3 value Kg/sq PI cm Mpa 361. 12.96 3689 77 377. 12.96 3846 17 392. 12.96 4000 27

E3 value Kg/sq PI cm Mpa 374. 12.04 3816 22 392. 12.04 4000 27 487. 12.04 4966 00

Native Soil + 4%Silica Fume load

Area 'Ac'

Kg

Sqcm

Stress (Kg/cm)

σ

31

σ

d

σ

Atterberg limits 11

LL

1

14.37

11.284

0.7

1.273

1.973

38.60

2

21.44

11.275

1.4

1.902

3.302

38.60

3

23.7

11.25

2.1

2.107

4.207

38.60

37

E3 value Kg/sq PI cm Mpa 424. 11.62 4333.3 95 490. 11.62 5000 34 502. 11.62 5125 59

Table 4.2.8 sample calculation at different confining pressure says 0.7, 1.4 and 2.1kg/cm2. Sl Type of No soil .

Days

1)

3

1)

3)

Native Soil(RS)

RS + % RBI-81

RS +% Silica Fume

3

3

Confinement pressure (kg/cm2)

E3 in kg/cm2 0%

1%

2%

4%

0.7

2430

-

-

-

1.4

2580

-

-

-

2.1

2751

-

-

-

0.7

-

3500

3600

3743

1.4

-

3622

3681

4090

2.1

-

3733

4090

4600

0.7

-

3689

3816

4333

1.4

-

3846

4000

5000

2.1

-

4333

4966

5125

Table 4.2. 10 Test result for %Dosage for 1.4 kg/cm2 confinements Atterberg limits

Load

Shear parameter Shear σd σ 31 strength (Kg/cm2) (Kg/cm2) (Kg/cm2)

Kg/cm2

Soil + % Stabilizer

LL

PI

Native (RS)

42.04

13.68

5.87

1.4

0.519

0.287

2580 253.01

42

13.24

10.35

1.4

0.917

0.361

3622 355.20

RS+1% RBI81

Kg

E3 value

38

Mpa

RS+2% RBI-81 RS+4% RBI-81

41.61 40.01

12.87 12.09

11.29 15.47

1.4 1.4

1.001 1.370

0.507 0.674

3681 360.98 4090 401.09

RS +1% SF RS +2% SF RS +4% SF

40 39.57 38.6

13.03 12.06 11.63

11.35 12.76 21.44

1.4 1.4 1.4

1.023 1.133 1.903

0.417 0.571 0.922

3846 377.17 4000 392.27 5000 490.34

Table 4.2.11 Shear Strength obtained for Native soil (RS) with % Dosage

σ

(Kg/cm2)

31

4.3.

Red soil (RS)

RS+1% RBI-81

Shear Strength kg/cm2 RS+2% RS+4% RS+1 RBI-81 RBI-81 % SF

RS+2 % SF

RS+4 % SF

0.7

0.213

0.308

0.434

0.557

0.337

0.534

0.811

1.4

0.287

0.361

0.507

0.674

0.417

0.571

0.922

2.1

0.311

0.422

0.581

0.791

0.454

0.652

1.032

Design of pavement:

Method 1 : By IRC-37 CBR method, Enter the Values For Design of Flexible Pavement as per ‘IRC37 Guidelines’ 8 CBR value (%) Length of road 40 km Type of Road

4 Lane Dual carriage way

Design life 'n'

10 IRC 37 Guidelines 0.07

Growth factor 'r' 4.5 VDF value 'F' Lane distribution factor 'D'

0.75

Initial traffic in the year of completion (CVPD) 'A' Cumulative num of

5000 85.101 39

msa

standard axle 'N'

N= (365*((1+r) A=P (1+r)

n

-1)*A*D*F)/r

x

Table shows Thickness obtained for different layers by CBR method , As per CBR method obtained thickness (mm) Indivial layer thickness

630

mt

unit cm

mm

0.04

4

40

0.14

14

140

0.25

25

250

0.2

20

200

0.63

63

630

BM DBM Base Sub-Base total

Method 2: By IRC-37 Annexure 1 method, Moduls of Elasticity of Subgrade, Sub-base and Base layers Step1

Input the data Elastic Modulus of Subgrade 'E3' (Mpa)

Thickness of Granular Layer 'h' (mm) / H2 Composite Elastic Modulus of granular Sub-Base and base 'E2' (Mpa)

254.5686 450 E2=E3*0.2*h0.45 795.76

Step2 Elastic Modulus of RBI81 'E1' (Mpa) Thickness of Granular Layer H2 (mm) Changed thickness using stabilizer 'H1' (mm)

40

505.68375

450 565

((E1 (H1)3)/ 12(1-µ12))= ((E2 (H2)3)/12(1-µ22)) From the above formula we calculate ‘H1’, µ is the Poisson’s ratio.

Table 4.2.12 shows the thickness variation with different %Dosage Native( RS)

soil

RS+1% RBI

RS+2% RBI

RS+4% RBI

RS+1% SF

RS+2% SF

RS+4 % SF

composite Elastic modulus of Granular Sub Base and Bas Layer(mm) E2 Kg/cm2 8114 8114 8114 8114 8114 8114 Mpa 795.76 795.76 795.76 795.76 795.76 795.76 Thickness reqd 588 584 564 576 568 528 rounded 575 570 530 thickness 590 585 565 20 20 20 chip carpet 20 20 20 Total 595 590 550 thickness 610 605 585

Table 4.2.13 shows the thickness variation by different layers soil + % RBI

Native RS

RS+1 % RBI

BC

40

-

DBM

140

-

chip carpet

-

BASE (WMM)

250

Thickness (mm)

SUBBASE (GSB) total Thickness

200 630

RS+2 % RBI

RS+4 % RBI

RS+1 % SF

-

-

-

-

-

-

-

20

20

20

20

20

20

590

585

565

575

570

530

610

605

585

595

590

550

--

41

RS+2 % SF --

RS+4 % SF -

4.4.

Materials Quantity Considering 4-lane dual carriage way with 4mt wide median and 2mt paved shoulder on either side. Table 4.2.13 materials required per km stretch. Materials required per Km in cum (as per IRC-37 CBR method) Native soil thickness (mm) BC DBM BASE (WMM) SUBBASE (GSB)

Qty (cum) 880 3080 5500 4400

Table 4.2.14 materials required per km stretch. material Required per Km Soil + % Stabilizer BM DBM Unit

Chip carpet

Base

Sub-Base

m3 -

m2 22000 22000 22000

m3

RS+1% RBI-81 RS+2% RBI-81 RS+4% RBI-81

m3 -

-

m3 -

RS +1% SF RS +2% SF RS +4% SF

-

-

22000 22000 22000

-

-

42

B&SB Replaced

Stabilizer Required(m3) Silica m3 RBI-81 Fume 12980 130 12870 257 12430 497 12650 12540 11660

-

127 251 466

4.5.

Cost analysis, Cost are estimated based on scheduled rates and are noted

6

.

Table 4 .2.15 Cost involved per m3 Cost per m 3 (in Rs.) as per SR PWD BM

DBM

Base

Sub-Base

Chip carpet

B&SB Replaced

Stabilizer per m 3

m3

m3

m3

m3

m2

m3

RBI-81

6000

5500

1400

1100

280

350

37

Table 4 .2.16 Cost involved per km of stretch as per CBR method design Materials required(cum) and cost involved per Km as per IRC-37 CBR method native soil BC DBM BASE (WMM) SUBBASE (GSB)

qty rate per cum 880 6500 3080 5500 5500 1450 4400 1100 Total cost(Rs).

43

Amount(Rs.) 57,20,000.00 1,69,40,000.00 79,75,000.00 48,40,000.00 3,54,75,000.00

Silica Fume 5

Table 4.2.17 Cost involved per km of stretch as per IRC-37 Annexure1 method. Material required per Km and cost estimated as per IRC-37 annexure method rate( amount(R rate( amount(R qty Rs.) s.) qty Rs.) s.) RBI 1% SF 1% Chip Chip carpet( sq 2200 62,70, carpet 2200 62,70, m) 0 285 000.00 sqm 0 285 000.00 1170 42,12, 1905 11,43, RBI in kgs 00 36 000.00 SF in kgs 00 6 000.00 1298 45,43, soil in 1298 45,43, soil in cum 0 350 000.00 cum 0 350 000.00 1,50,25,0 1,19,5 Total Cost 00.00 Total Cost 6,000.00

qty RBI 2% Chip carpet( sq m) RBI in kgs soil in cum

2200 0 2313 00 1287 0

Total Cost

qty RBI 4% Chip carpet( sq m) RBI in kgs soil in cum

2200 0 4473 00 1243 0

rate( Rs.)

amount(R s.)

62, 285 70,000

qty SF 2% Chip carpet sqm

83, 36 26,800 45, 350 04,500 1,91 ,01,300 rate( Rs.)

SF in kgs soil in cum

Total Cost

amount(R s.)

62, 285 70,000 1,61, 36 02,800 350 43, 50,500 44

2200 0 3765 00 1287 0

qty SF 4% Chip carpet sqm SF in kgs soil in cum

2200 0 6840 00 1243 0

rate( Rs.)

amount(R s.)

62,70, 285 000.00 22,59, 6 000.00 45,04, 350 500.00 1,30,3 3,500.00 rate( Rs.)

amount(R s.)

62,70, 285 000.00 41,04, 6 000.00 350 43,50, 500.00

Total Cost

2,67 ,23,300

1,47,2 4,500.00

Total Cost

Table 4.2.18 Abstract of Modulus of sub grade, plastic index, thickness and cost with % relationship at 1.4kg/ sqcm confinement pressure. soil + Native RS+1 % RS+2 % % RBI RS RBI RBI Dosag 0 1 2 e (%) PI 13.68 13.24 12.87 Total thickne 630 610 605 ss (mm) total cost(Rs 3,54,75, 1,50,25 1,9 .) 000 ,000 1,01,300 Modulus of Sub-grade E3 (@ 1.4kg/sqcm confinement pressure) Kg/cm 2 2580 3622 3681 Mpa 253.01 355.2 360.98 % Decrea se in thickne ss 0 3.17 3.97 % Saving s 0 57.65 46.16 % increas e in E3 value 0.00 40.39 42.67

RS+4 % RBI

RS+1 % SF

RS+2 % SF

RS+4 % SF

4

1

2

4

12.09

13.03

12.06

11.63

585

595

590

550

2, 67,23,30 0

1,19,56, 000

1,30,3 3,500

1,47, 24,500

4090 451.11

3846 377.17

4000 392.27

5000 490.34

7.14

5.56

6.35

12.70

24.67

66.30

63.26

58.49

58.53

49.07

55.04

93.80

The above graph1 shows % decrease in Thickness verses % Dosage of stabilizer

45

The above graph2 shows % increase in modulus value verses % Dosage of stabilizer

The above graph3 shows % Savings in cost verses % Dosage of stabilizer

CHAPTER-5 DISCUSSION AND CONCLUSION

1.1

Discussion

The study of soil characteristics and the analysis is very important aspect in the design of the pavement which involves several complexities due to variable factors. This study is aimed at evaluating the strength properties of the given soils by stabilization using the given stabilizers and the results are compared. ➢ Plastic index was reduced when % Stabilizer dosage increased. But % decrease was greater when Silica Fume was used. ➢ Shear strength was also increased when specimen was subjected to Triaxial test with

different confinement pressure with different dosage. But the specimen with 4% RBI-81 showed shear failure at a confinement pressure of 0.7kg/cm2. But with same % of Silica fume as stabilizer, bulging was observed .So from above point of view infra that with increase in RBI dosage the stabilized layer shows rigid behavior. ➢ Young’s modulus of stabilized soil also increased with increase in % stabilizer dosage to about 60% and 90% with RBI-81 and Silica Fume as stabilizer. ➢ All the above observations are based on 3days moist curing.

46

➢ Design

of pavement as per IRC-37 based on CBR showed required thickness of

630mm(BC=40mm,DBM=140mm,Base=250mm,Sub-Base=200mm), and cost involved was around 3.6cr for 4-lane dual carriage way with 4mt median and 2mt paved shoulder on either side, as per scheduled rate for materials. ➢ When design was compared with IRC-37 Annexure method the thickness of pavement

was reduced by replacing all the layers with stabilized locally available soil, here the Modulus of elasticity was taken at confining pressure of 1.4kg/sqcm.

➢ From above design with different stabilizer shows that, when the Silica Fume as

stabilizer with 4% dosage at confining pressure of 1.4kg/ sqcm the thickness was reduced by around49% with bulging . Similarly when RBI-81 as stabilizer the thickness was reduced around 28% with shear failure. ➢ Comparing with the cost estimated it showed around 46% and 62% savings with RBI-81

and Silica Fume as stabilizer with 2% dosage.

1.1

Conclusion The conclusion given below are based on 3 days moist curing and testing for Sandy clayey(SC) type of soil which was classified based on IS-Classification. And rates as per scheduled rate6. ➢ The above results when compared shows Silica Fume can be used as stabilizer. ➢ When Silica fume as stabilizer comparing with RBI-81 with 2 and 4%dosage shows around 15 and 30 % savings compared with conventional method design. ➢ As test are need to be carried out for more soil samples and allowing for moist

curing for more number of days and observing the failure characteristic which type stabilizer to use can be suggested . ➢ As the above design method i.e. (IRC-37 Annexure) pavement thickness obtained need be studied with trial stretch, observations are need to be made. 1.1

Scope for future studies

47

Since Silica fume is a byproduct it may be harmful for environment, using such materials for construction in different forms at different level may reduce the harmful effect in future. ➢ Since Silica Fume as Cementitious property it can be used in highway construction. ➢ Studies have be carried out for different types of pavement with waste materials like

Silica Fume, as stabilizer or partially replacing cement in rigid pavement or with silica fume alone.

References 1.

Highway Engineering by S.K.Khanna and C.E.G. Justo.

2.

Highway materials and pavement testing by S.K.Khanna - C.E.G. JustoA.Veeraragavan.

3.

Geotechnical Engineering by T.N.Ramamurthy and T.G. Sitharam.

4.

Highway Engineering by Dr.L.R.Kadyali and Dr.N.B.Lal.

5.

http://www.icjonline.com/views/2002_07_Singh.pdf, http://greenbuildings.santa-monica.org/appendices/apamaterials.html

6.

www.chronicindia.org suppliers in Silica Fumes.

7.

Civil Engineering Materials by Handoo, Mahajan Kaila.

8. IRC-37 Guidelines for design of flexible pavements by Indian Road Congress

48

Annexure 1 Shows Triaxial compression test (Stress verses Strain) Graphs with different %dosage at 0.7, 1.4 and 2.1kg/sqcm confinement pressure. 1. Triaxial test result Graphs for Native Red Soil (RS) at 0.7kg/sqcm confinement pressure.

2. Triaxial test result Graphs for Native Red Soil (RS) at 1.4 kg/sqcm confinement pressure.

3. Triaxial test result Graphs for RS +1% RBI-81 at 0.7 kg/sqcm confinement pressure.

49

4. Triaxial test result Graphs for RS +1% RBI-81 at 1.4 kg/sqcm confinement pressure.

5. Triaxial test result Graphs for RS +1% RBI-81 at 2.1 kg/sqcm confinement pressure.

6. Triaxial test result Graphs for RS +2% RBI-81 at 0.7 kg/sqcm confinement pressure.

7. Triaxial test result Graphs for RS +2% RBI-81 at 1.4 kg/sqcm confinement pressure.

8. Triaxial test result Graphs for RS +2% RBI-81 at 2.1 kg/sqcm confinement pressure.

9. Triaxial test result Graphs for RS +4% RBI-81 at 0.7 kg/sqcm confinement pressure.

10. Triaxial test result Graphs for RS +4% RBI-81 at 1.4 kg/sqcm confinement pressure.

11. Triaxial test result Graphs for RS +4% RBI-81 at 2.1 kg/sqcm confinement pressure. 50

12. Triaxial test result Graphs for RS +1% SF at 0.7 kg/sqcm confinement pressure.

13. Triaxial test result Graphs for RS +1% SF at 1.4 kg/sqcm confinement pressure.

14. Triaxial test result Graphs for RS +1% SF at 2.1 kg/sqcm confinement pressure.

15. Triaxial test result Graphs for RS +2% SF at 0.7 kg/sqcm confinement pressure.

16. Triaxial test result Graphs for RS +2% SF at 1.4 kg/sqcm confinement pressure.

17. Triaxial test result Graphs for RS +2% SF at 2.1 kg/sqcm confinement pressure.

18. Triaxial test result Graphs for RS +4% SF at 0.7 kg/sqcm confinement pressure.

19. Triaxial test result Graphs for RS +4% SF at 1.4 kg/sqcm confinement pressure.

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20. Triaxial test result Graphs for RS +4% SF at 2.1 kg/sqcm confinement pressure.

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