Chapter 5123

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CHAPTER 5

Effect of coir fiber and other additives on the Geotechnical Properties of

Stabilized BC soil.

5.1 ntrod!ction

Highly clayey and black cotton soil shall not be used directly as subgrade material for

pavement construction in such cases, if the insitu soil does not fulfill the requirements of

normal subgrade soil, either soil from other sites has to be used or the available soil has to be

stabilized so that it attains sufficient strength to carry the traffic load. Soil stabilization is

gained great importance in road construction. The use of pozzolonic materials such as

cement, fly ash, lime and other materials is well established to improve the properties of the

soil. In this chapter the detailed eperimental programme has been planned to study the effect

of artificial fiber and natural fiber on the geotechnical properties of !ement and other

stabilized soil. "lternative techniques are required to provide by civil engineers to traditional

stabilization technique, since traditional stabilization techniques require large amount of

additives by dry weight to improve the engineering properties of materials. #any of these

techniques require specialized skills and equipment to ensure adequate performance, which is

not feasible especially for low volume roads. $ploring the feasibility of such alternatives for the benefit of road building sector to evolve a stronger durable and economic design is the

goal of this research. To achieve the economy and to reduce the requirement of large quantity

of chemical stabilizers like cement, lime %&I'() etc and also to improve the other

geotechnical properties of chemically stabilized soil, fibers with and without chemical

stabiliser has been used in this study for altering the properties of &! soil is presented.

The effect of fibers on #**, +#!, !S and !&% of &lack cotton soil stabilized with

cement and %&I'() has been found to be limited in literature, the ob-ective of this chapter is

to study the effects of fiber on geotechnical properties of epansive soil stabilized with

different chemicals.

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5." E#peri$ental Pro%ra$$e

It is recognized that research as well as performance trials have not been very

etensive in India for some of the new materials, I%! /0'12)1 guide lines for the design of

fleible pavements3 thus no data is available to fi up the optimum content of commercially

available polymers, chemical stabilisers and industrial wastes, this research work reported

encompass many diversified aspects but primarily concentrated on materials and mies,

based on the requirement and the current practice in India the percentages of polypropylene

fiber and other chemical additives are selected. The criteria adopted were !alifornia bearing

ratio test results which directly depends geotechnical properties like #**, +#!, 4iquid

4imit and !!."s the !&% value of the subgrade increases, the total pavement thickness decreases,

thereby decreasing the pro-ect cost, thus the proportion of mi was done on trial basis

keeping in view to achieve maimum !&% value by making use of available %einforcing

materials, chemical additives and Industrial wastes, table 5.) summarises the eperimental

programme.

"s per eperimental programme Shown in Table5.), the optimum percentages of &oth

6ibers and other additives to be added to &lack cotton soil has been determined based on

liquid limit, plasticity inde, compaction characteristics and unconfined compression test

results. The tests were conducted as per IS Standard. Table 5.1 to 5.)1 and 6ig5.) to 6ig5.)1

presents the plasticity characteristics of stabilized soils with different percentages of !ement,

%&I'(), 7olypropylene fiber 87769, !oir fiber, 6ly ash, 4ime and their combination.

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Table 5.1 E#peri$ental Pro%ra$$e for BC Soil and Additives

!ombination $periments !onducted !uring period in *ays

&! "loneSpecific :ravity, 44, 74, S4, :rain size

analysis, !ompaction, !S ;!&% Immediate

&! soil and 1(

&! soil =!ement

&! soil

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!ontinued

Table 5.1 E#peri$ental Pro%ra$$e for BC Soil and Additives

!ombination $periments !onducted !uring period in *ays

&! "loneSpecific :ravity, 44, 74, S4, :rain size

analysis, !ompaction, !S ;!&% Immediate

&! soil and1(

&! soil

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&! Soil

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resistance at the particle level and 8ii9 the thickness of diffused double layer. "lthough the

liquid limit of clays is governed by the shearing resistance at particle level, the contribution

due to diffused double layer overrides and primarily governs the liquid limit 8Sridharan et al

)A(?9.

5.&.1.1 Effect of ce$ent on blac- cotton soil

The etent to which soil properties get modified by cement action depends greatly on

the concentration of cement, with cement in the range of 0 to )2 percent, depending on other

factors the miture may develop considerable compressive strength, I%! 52')A0(3 keeping

this in view, the percentage of cement content was restricted to ( percent

:ravely, Sandy, clayey type of soils can be stabilized using cement, whencomparatively higher and faster development of strength and durability characteristics are

needed especially for waterlogged and high rainfall areas.8I%!BS7B12'12219.

The 4iquid limit and 7lastic limit of &! soil alone is >5.0 and 11.)> respectively,

hence treating it as medium clayey soil, It could be observed from the table5.) that with

increase in percentage of cement from 1 =to (= there was ).05=, 0.1=, A=and)>=

reduction in 4iquid limit of &! soil and of 7lasticity inde of the soil reduced by

)1=,1/./2=,/5.(?= and 5)= respectively. This is attributed to the reason that the clayey

soil is being mied with the non plastic material, cement. The 4iquid limit and 7lastic limit of

&! soil with various percentage of !ement is as shown in the table5.1 and figure5.).

Table 5." Plasticit/ characteristics of Ce$ent Stabilized BC Soil

Ce$ent 0 (i,!id (i$it Plastic (i$it Plasticit/ nde#

>5.02 11.)> 1/.5?

" >>.A2 1>.)? 12.0>

2 >1.>1 1>./5 )(.20

3 >).?2 1?.>A )5.))

4 /A.1A 10.(? )).>/

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i% 5.1 6ariation of (i,!id (i$it7 Plastic (i$it and Plasticit/ nde# 8ith increase in

percenta%e of Ce$ent.

5.&.1." Effect of RB941:road b!ildin% international %rade 41; on blac- cotton soil

%&I :rade'() was originally developed by %&I for South "frican "rmy %oad

&uilding International in the beginning of )AA2Cs for pavement engineering applications.

%&I'() is a natural inorganic, soil'stabilizer which re'engineers and modifies the properties

of the soil strength for roads, "lchemist Technology is the eclusive manufacturer anddistributor of %&I :rade'() in India, since it is new material to India there is no codal

provisions were developed. %&I'() is a unique and highly effective natural inorganic soil

stabilizer for Infrastructure development and repair. The physical and chemical composition

of this material is discussed in !hapter >.

4iquid limit tests have been carried out by adding various percentages of %&I'()

stabilizers to &lack !otton soil. The 4iquid limit of &! soil decreases with the addition of

%&I'() stabilizer. The 4iquid limit and 7lastic limit of &! soil with various percentage of

%&I'() stabilizer is as shown in the table5./ and figure5.1

Table 5.& Plasticit/ characteristics of RB941 Stabilized BC Soil

RB941 0 (i,!id (i$it Plastic (i$it Plasticit/ nde#

>5.0 11.)> 1/.?2

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" >>.?2 1/.A2 12.02

2 >1.0> 1>.05 )0.AA

3 /A.>2 1?.0A )1.?)

4 /(.A2 10.(( )).21

i% 2.& 6ariation of (i,!id (i$it7 Plastic (i$it and Plasticit/ nde# 8ith increase in

percenta%e of RB.

5.&.1.& Effect of pol/prop/lene fibre :PP; on blac- cotton soil

#ost of the researchers are reinforced polypropylene with sand to determine the

behaviour of material properties of fiber reinforced sand. 4imited studies have been carried

out on fibers reinforced with epansive soil, that to they didnCt find any scope in finding the

effect on plasticity characteristics, addition of fiber to &! soil is a type of mechanical

stabilisation, thus there is no chemical reaction formation contributing increase or decrease of

liquid limit

6iber reinforcement of soils has been a sub-ect of research for so many years, the

main ob-ective of this study is to predicting response of &! soil reinforcing with %andomly

distributed discrete fibre of length )2')1mm under the static and cyclic loading process.as per

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the eperimental programme the 4iquid limit tests and plastic limit tests have been carried

out by adding various percentages of 776 stabilizer to &lack !otton soil. &oth 4iquid limit of

&! soil and 7lastic limit value of &! soil Increases with the addition of 776. The 4iquid limit

and 7lastic limit of &! soil with various percentage of 776 stabilizer is as shown in the

table5./ and figure5.1

Table 5./ shows liquid limit of &! soil decreases with addition of fiber and decreases

further with increase in fiber content this is due to the soil is replaced by fiber having surface

area of fiber is less compared to clay grains leads to the decrease in liquid limit.

Table95.& Plasticit/ characteristics for Blac- Cotton Soil 8ith ibers

!ombination 44 74 7I

&! Soil "lone/.A 20 1/.A2

&! Soil "lone0.0? 21.59 1?.)0

&! Soil "lone(.5 21.97 1?.5/

&! Soil "lone

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i%95." Atterber% (i$its for Blac- Cotton Soil

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%&I'() is used for pre'treatment for clayey soil before miing with the cement, the

quantities of %&I'() and cement must be determined on the basis of unconfined compressive

strength, generally cement content ranges from /= to 5 = by weight of dry soil 8I%!B S7B 129

since %&I'() is new material and doesnCt have any codal provisions, in this study we selected

)= to 5= by weight of dry soil along with the cement to study the effect of %&I'cement mi

on the plasticity characteristics of &! soil.

4iquid limit and 7lastic limit tests have been carried out by adding both cement and

%&I'() to &lack cotton soil. The combined effect of above mentioned additives on the liquid

limit of black cotton soil have been studied. The liquid limit of &lack cotton soil alone is

found to be >5.0=. +n addition of these additives 4iquid limit decreases, this may due to

addition of courser particles causing reduction in clay content of the miture. The variation of

liquid limit and plastic limit of &lack cotton soil for different content of additives is presented

in table5.> and fig5./

Table 5.2 Plasticit/ characteristics of Ce$ent = RB Stabilized BC Soil

BC

Soil=Ce$ent=RB941

:0;

(i,!id (i$it Plastic (i$it Plasticit/ nde#

>5.0 11.)> 1/.?

" >>.0> 1>.2) 12.0/

2 >1.(5 1>.A )0.A5

3 >2./1 1?.(( )/.>>

4 /A.) 1(.)/ )2.A0

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i% 5.& 6ariation of (i,!id (i$it7 Plastic (i$it and Plasticit/ nde# 8ith increase in

percenta%e of Ce$ent = RB.

5.&.1.5 Effect of Pol/prop/lene fiber on ce$ent stabilised BC soil.

&ased on the limited literature available on fiber reinforced with &! soil and from the

present study it can be eplained that the decrease in 4iquid 4imit with addition of fiber

content is attributed to the decrease in 4iquid limit and increase in plastic limit is nothing but

gain in strength and decrease in plasticity Inde shows that the volume change is less with

the addition of fibers,

The combined effect of !ement and 7olypropylene 6iber on the liquid limit of black

cotton soil have been studied with varying percentage of mitures, here also there is no much

significant change in the trend was +bserved. The variation of liquid limit of &lack cotton

soil treated with varying percentage of mitures is shown in the figure5.> and table5.5.

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Table 5.5 Plasticit/ characteristics of Ce$ent = PP Stabilized BC Soil

!ement5.0 11.)> 1/.?

)=

!ement>.?1 11.?> 1).A(

1=

!ement5.2? 1>.?0 12./A

/=

!ement?.11 10./) )(.A)

>= !ement1.5? 1(.?0 )/.(A


percenta%e of Ce$ent = PP.

5.&.1.3 Effect of pol/prop/lene fiber on RB941 stabilised BC soil

The effect of 7olypropylene 6iber on the liquid limit of %&I'() stabilised black

cotton soil have been studied with varying percentage of mitures, here also there is no much

significant change in the trend was +bserved. The variation of liquid limit of &lack cotton

soil treated with varying percentage of mitures is shown in the figure5.5 and table5.?.

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Table 5.3 Plasticit/ characteristics of RB = PP Stabilized BC Soil

RB941=PP 0 (i,!id (i$it Plastic (i$it Plasticit/ nde#

>5.0 11.)> 1/.5?

)= %&I>./> 1/.(1 12.51

1= %&I1.>5 1>.5/ )0.A1

/= %&I= %&I

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5.&.1.> Effect of Coir ibre on Blac- cotton soil

Here an attempt is made to make use of fibrous coir waste from the coir industry to

stabilise &! soil subgrade. 4oose fibrous coir fibre is collected from the !oir &oard, 7eenya

Industrial "rea, &angalore. 6ibrous coir of fine gradation and specific gravity 2.0 was

selected for soil stabilization studies. The selected fibres are having aspect ratio )22 with

average length of /2mm and diameter 2./ mm .The methodology involved was miing the

discrete coir fibers with soil at different proportions to study the changes in the 4iquid limit

and 7lasticity Inde of the soil'coir matri. It is seen in figure 5.? that with increase in coir

fibre content there is reduction in plastic limit and plasticity inde of soil'coir mi

Table 5.> Plasticit/ characteristics of Coir iber Stabilized BC Soil

BC S+( =C+R BRE 0 (i,!id (i$it Plastic (i$it Plasticit/ nde#

2.1= >5./ 11.>> 11.(?

2./= >>.A 1/.?> 1).1?

2.>= >1.?/ 1>.1? )(./0

2.5= /A.A? 1?.(A )/.20


percenta%e of Coir fiber

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5.&.1.4 Effect of l/ ash on Blac- cotton soil

To study the effect fly ash on plasticity characteristics of soil, different percentages of

fly ash viz., )2, 12, and /2 were mied with soil and liquid limit and plastic limits were

determined. The variation of liquid limit and plasticity inde are shown in Table 5.( and

figure 5.0 respectively.

It is seen in figure 5.0 that with the increase in percentage of flyash, there is reduction in

liquid limit and plasticity inde of soil fly ash miture.

Table 5.4 Plasticit/ characteristics of l/ash Stabilized BC Soil

BC S+( = l/ Ash (i,!id (i$it Plastic (i$it Plasticit/ nde#

)2= >/.0 1).)1 11.5(

12= >1 1/.>? )(.5>

/2= // 1>.A( (.21

i% 5.> 6ariation of (i,!id (i$it7 Plastic (i$it and Plasticit/ nde# 8ith increase in

percenta%e of l/ash

5.&.1.? Effect of (i$e on Plasticit/ characteristics Blac- cotton soil

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It is known that addition of lime 8i9 reduces the thickness of diffuse double layer of

clay particles by increasing the electrolyte concentration and by echanging monovalent

cation by divalent calcium ion, leads to decrease in 4iquid limit, and 8ii9 causes flocculation

of clay particles which leads to increase in the liquid limit 8Eayadev and Sridharan, )A(19.

The increase in the liquid limit of black cotton soil immediately on addition of 1= lime

shows that the effect of flocculation dominates over the effect of decrease in the double layer

thickness. &y increasing the lime content beyond 1= the liquid limit reduces because

Fhen the local soil, cannot be economically and effectively stabilised by mechanical

methods, the chemical stabilisation of these materials are resorted to. 4ime stabilisation is

normally adopted for silty clays and clayey soils including black cotton soil. The

development of strength in soil lime mies depends on the type of clay and its quantity in

soils.thus, lime stabilisation is recommended for soils having 7IG(.it is desirable that the

calcium hydroide content in lime for stabilisation should be more than 02 percent. In case of

inferior lime the quantity of lime for stabilisation has to be increased proportionately. 4ime

with purity less than 52percent should not be normally used. 8I%!B S712'12219.

To study the effect 4ime on plasticity characteristics of soil, different percentages of

4ime viz., 1=,>=,?=and(= were mied with soil and liquid limit and plastic limits weredetermined. The variation of liquid limit and plasticity inde are shown in Table 5.A and

figure 5.( respectively. It is seen in figure 5.( that with the increase in percentage of 4ime,

there is reduction in liquid limit and plasticity inde of soil 4ime miture.

Table95.? Plasticit/ characteristics for Blac- Cotton Soil 8ith (i$e

Sl.2 S+I4 44 74 7I

) &! Soil "lone < 1= 4I#$ >(.A> 17.86 /).2(

1 &! Soil "lone < >= 4I#$ >0.? 19.36 1(.1>

/ &! Soil "lone < ?= 4I#$ >?./1 20.2 1?.)1

> &! Soil "lone < (= 4I#$ >5.0 21.3 1>.>

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percenta%e of (i$e

5.&.1.1 Effect of coir fiber on li$e stabilised blac- cotton soil.

!oir is a natural biodegradable organic fiber material the rate of decomposition of coir

fibre is generally known to be less than that of any other natural fibers, coir retains 12= of its

strength even after one year 8Shivakumar babu et al9 the main advantages of coir fibers

compared to other natural fibers are its high initial strength, stiffness and hydraulic

properties. If the requirement is for shorter period then coir is the best choice due to its

biodegradability compared to synthetic fibre.

It is has to be used for longer period, then the chemical treatment like lime is used

along with coir fibers. The inclusion of fibre reinforcement within soil and lime'soil mi

caused an increase in the strength, the increase in strength of combined fibre and lime

inclusion is much more than the increase caused by them individually.

To study the effect of !oir'4ime matri on plasticity characteristics of soil, different

percentages of coir'4ime were mied with soil and liquid limit and plastic limits were

determined. The variation of liquid limit and plasticity inde are shown in Table 5.A and

figure 5.( respectively.It is seen in figure 5.( that with the increase in percentage of 4ime,

there is reduction in liquid limit and plasticity inde of soil 4ime miture.

Table 5.1 Plasticit/ characteristics of Coir fiber = (i$e Stabilized BC Soil

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(@E=C+R BRE

0(i,!id (i$it Plastic (i$it Plasticit/ nde#

)= < 2.)= >(.5) )?.)0 /1./>

1= < 2.)5= >?.A? )(.A/ 1(.2/

/= < 2.1= >5.(? 1).2/ 1>.(/>= < 2.15= >>.0/ 11.5? 11.)0

i% 5.? 6ariation of (i,!id (i$it7 Plastic (i$it and Plasticit/ nde# 8ith increase inpercenta%e of Coir fiber (i$e

5.&.1.11 Effect of Coir fiber on fl/ ash stabilised Blac- cotton soil.

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The dominant mechanism controlling reinforcement benefit seems to be the bond

strength and friction at the interface of fibre reinforced soil, interactions occur at the interface

between the fibre surface and the clay grains play key roles in the mechanical behaviour,however in fibre reinforced flyash soil the interactions between the fibre surface and the

hydrated products make main contribution to the strength at the interface. It is known that the

interface roughness plays an important role in reinforced soil systems.

4iquid limit and 7lastic limit tests have been carried out by adding various

percentage of !oir'flyash mi to &lack cotton soil. The 4iquid limit of &lack cotton alone

is>5.0=. The liquid limit of &lack cotton soil decreases with the addition of !oir'flyash mi.

The liquid limit of &lack cotton soil mied with various percentage of !oir'flyash matri is

as shown in the table5.)) and figure5.)2.

Table 5.11 Plasticit/ characteristics of Coir fiber = l/ash Stabilized BC Soil

C+R BRE0 =

(ASH0(i,!id (i$it Plastic (i$it Plasticit/ nde#

2.)= < 5= >5.0/ 11.>? 1/.10

2.)5= < )2= >>.(? 1/.)? 1).0

2.1= < )5= >>.)) 1/.(/ 12.1(

2.15= < 12= >/.5? 1>.1/ )A.//


percenta%e of Coir fiber = l/ash.

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5.&.1.1"Effect of l/Ash on li$e stabilised blac- cotton soil

" miture of fly ash and soil, when stabilised using lime is called lime 6ly"sh

Stabilised Soil 8I%!B S7B 12'12219. This material can be used for constructing sub'base or

base course of rural roads. The use of stabilised fly ash subbase course would be particularly

attractive in locations where flyash is easily available and supplies of aggregates are

unavailable or epensive. It is possible to construct lime flyash stabilised layer without

admiing soil for sub'base layer. This would increase the utilisation of flyash and also

prevent usage of topsoil.

To study the effect 4ime6ly"sh on plasticity characteristics of soil, different percentages of

4ime and fly ash viz., )=,1=,/=,>=and 5=,)2=,)5=and12= were mied respectively with

soil and liquid limit and plastic limits were determined. The variation of liquid limit and

plasticity inde are shown in Table 5.)) and figure 5.)1 respectively.It is seen in figure

5.))that with the increase in percentage of 4imeflyash, there is reduction in liquid limit and

plasticity inde of soil'4ime miture.

Table 5.1" Plasticit/ characteristics of l/ash and (i$e Stabilized BC Soil

(@E = (ASH 0 (i,!id (i$it Plastic (i$it Plasticit/ nde#

)= < 5= >(./1 )0.A? /2./?

1= < )2= >?.(A )A.)/ 10.0?

/= < )5= >>.5/ 12.2( 1>.>5

>= < 12= >/.?1 1).)? 11.>?


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percenta%e of l/ash = (i$e

5.&."Co$paction Characteristics

In any highway engineering work, the construction of the embankment or subgrade is

a very important activity. The earth work constitutes /2= of the cost of the road pro-ect. The

road pavement directly rests on the artificially prepared soil subgrade and thus derives

considerable strength from it. The adequate design and construction of embankment is

therefore the key to the successful performance of roads.

$portance of ade,!ate co$paction of earth 8or-

The properties of soil used in the roads are improved by a process called stabilization. This is

done either by mechanical means by compaction or by adding additives or chemical to soil

due to compaction the air present in the soil is epelled to bring the soil grains to denser state.

!ompaction results in an increase in heavy ale load carrying capacity of the pavement. "

densified subgrade soil mass undergoes little change in volume under traffic loads, thus

minimizing deformation and maintaining good rideability characteristics of the pavement

surface. " compacted soil reduces the ingress of water, thereby making the subgrade less

vulnerable to changes in moisture conditions. Fell compacted subgrade results in economy of

the pavement thickness. 7roper compaction results in an overall increase of the economy of

the road pro-ect.

actors infl!encin% the co$paction of soil

" given soil can be compacted by several methods resulting in different degrees of

compaction. Similarly a type of compaction applied to different soils may again yield varied

degrees of compaction. This suggests that there are many factors, which have a bearing on the

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degree of the compaction.

Co$paction Effort

!ompaction which is the process of packing soils closer depends upon the energy applied per

unit weight of soil. The higher the energy input, the greater is the compaction this is true for

all types of soils and all methods of compaction. The energy input depends on the weight of

the rammer the height of fall and the number of blows in the case of laboratory compaction.

Effect of $oist!re content

The behavior of the soil at different moisture contents can be eplained as follows, when the

moisture content is low, the soil is stiff and difficult to compress thus low dry density and

high air contents are obtained. "s the moisture content increases the water acts as a lubricant,

causing the soil to soften and become more workable. This results in higher dry densities and

lower air contents. "s the air content becomes less the water and air in combination tend to

keep the particles apart and present any appreciable decrease in air content. The total voids

however continue to increase with the moisture content and hence the dry density of the soil

falls. Fell graded materials have relatively sharp moisture'density curves, on the other hand

soils which are poorly graded or uniformly graded have relatively flat moisture'density

curves.

Effect of soil t/pe

Type of soil has a great influence on its compaction characteristics. ormally heavy clays and

silts offer higher resistance to compaction, whereas sandy soils and coarse grained or gravelly

soils are amenable for easy compaction. The coarse grained soils yield higher densities in

comparison of a clay soils. The gradation of the soil is an important factor. " well graded soil

gets compacted with lesser compactive effort to higher densities. Therefore coarse grained

soils without any fines may not be able to attain high density.

!ompaction is the process of the density of the soil by packing the particles closer

together with reduction in the volume of air. *ensification of soil improves their engineering

properties. Jarious advantages of compaction of soils include 8i9 reduction of subsidence

from the reduced void ratio, 8ii9 increase in soil strength, 8iii9 reduction in the settlement.

The modified proctor tests were performed on the selected soil,!ement,776,%&I'()

and Jarious combination as presented in $perimental 7rogramme, after the preparation of

miture in accordance with the specification laid in IS10128part'(9)A(2 to study the

compaction characteristics. The maimum dry density and the optimum moisture content

values obtained by conducting these tests for untreated soil and soil treated with different

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percentages of additives are shown in Table. The variation of maimum dry density and

optimum moisture content with the increase in percentage of fly ash is shown in 6igure

respectively

.

5.&.".1 Effect of Ce$ent on co$paction characteristics of BC soil

+rdinary 7ortland cement is composed of calcium'silicates and calcium'aluminates

that when combined with water, hydrate to form the cementing compounds of calcium'

silicate hydrate and calcium'aluminate hydrate as well as calcium hydroide8lime9. &ecause

of the cementitious material as well as the calcium hydroide formed, 7ortland cement may

be successful in stabilizing both granular and fine grained soils. " pozzolonic reaction

between the calcium hydroide released during hydration and soil alumina and soil silica

occurs in fine' grained clay soils and is an important aspect of the stabilization of these soils.

!ompaction tests have been carried out on &! soil alone. The #aimum dry density

of &! soil alone is )?.0Km/ and optimum moisture content of 12.2(=. on addition of

!ement to &lack cotton soil the maimum dry density increases as shown in Table 5.)/

and figure5.)1 and "S per I%! 52')A0/is a code of L%ecommended design criteria for the

use of !ement'#odified soil In %oad constructionM at clause 1.1 it has been shown that

even with small concentrations of cement, of the order of 1 to /= a soil could develop

adequate strength to satisfy the requirement of a road sub'base. Since the test is stopped at

(= cement content.

Table 5.1& @** 6al!es +@C 6al!es for Blac- Cotton Soil 8ith 6ario!s

Percenta%e of Ce$ent

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i% 5.1" @** and +@C for Blac- Cotton Soil 8ith 6ario!s Percenta%e of

Ce$ent

5.&."." Effect of RB941 on co$paction characteristics of blac- cotton soil

!ompaction tests have been carried out by adding %&I'() to &lack cotton soil, the

maimum dry density and +ptimum moisture content increases with increase in %&I'()

content. 6rom the Table 5.)> the maimum dry density for 1=, >=, ?= ; (= of %&I mied

Sl.2 S+I4

#**

8gcc9 +#! 8=9

) &! Soil < 1= !ement ).0> 12.5?

1 &! Soil < >= !ement ).00 1).(1

/ &! Soil < ?= !ement ).0( 11.22

> &! Soil < (= !ement ).0A 11.)(

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with soil have increased by >.)A=, 5./(=, 5./(= ; 5.A(= respectively as compared to the

#** for soil alone, whereas the +#! for 1=, >=, ?= ; (= have increase by 5.21=,

A.5?=, )1.25= ; )?.(/= respectively as compared to the +#! for soil alone.

Table 5.12 @** 6al!es and +@C 6al!es for Blac- Cotton Soil 8ith 6ario!s

Percenta%e of RB941

i% 5.1& @** and +@C for Blac- Cotton Soil 8ith 6ario!s Percenta%e of RB

5.&.".& Effect of rando$l/ distrib!ted7 discrete pol/prop/lene ibers:PP; on

co$paction characteristics of blac- cotton soil

Sl.2S+I4 #** 8gcc9 +#! 8=9

) &! Soil < 1= %&I'() ).0> 1).2A

1 &! Soil < >= %&I'() ).0? 11.22

/ &! Soil < ?= %&I'() ).0? 11.52

> &! Soil < (= %&I'() ).00 1/.>?

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The #** of &! soil decreases and +ptimum moisture content increases with

increase in percent of polypropylene, this compaction test results in Table5.)5 and figure 5.)>

showed that the fibers increased the resistance to densification, when a constant compactive

effort was applied to samples with increasing fiber content, the strength either increased

hardly at all or actually decreased. This was caused by the concomitant increase in porosity

that occurred with increasing fiber content. %ather +#! of &! soil increases because

7olypropylene is a synthetic, inorganic material it want absorb water un like in natural coir

fiber.


Percenta%e of PP

Sl.2 S+I4 #** 8gcc9 +#! 8=9

) &! Soil "lone( )5./5

1 &! Soil "lone)

/ &! Soil "lone5

> &! Soil "lone )?.()

5 &! Soil "lone/

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i%95.12 @** and +@C for Blac- Cotton Soil 8ith 6ario!s Percenta%e of

Pol/prop/lene fibres.

5.&.".2 Effect of Ce$ent on co$paction characteristics of RB941 stabilised BC soil

6rom the Table 5.)? and 6igure5.)5 the maimum dry density for )=, 1=, /= ; >=

of cement content and )=, 1=, /= ; >= of %&I content mied with soil have increased by

>.)A=, 5./(=, 5.A(= ; 0.0(= respectively as compared to the #** for soil alone, whereas

the +#! for 1=, >=, ?= ; (= have increase by 1./A=, A./?=, )).)5= ; )/./>=

respectively as compared to the +#! for soil alone.


Percenta%e of Ce$ent = RB

Sl.2 S+I4 #** 8gcc9 +#! 8=9

) &! Soil < )= !ement < )= %&I'() ).0> 12.5?

1 &! Soil < 1= !ement < 1= %&I'() ).0? 1).A?

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/ &! Soil < /= !ement < /= %&I'() ).00 11./1

> &! Soil < >= !ement < >= %&I'() ).( 11.0?


Ce$ent = RB

5.&.".5Effect of rando$l/ distrib!ted PP on co$paction characteristics of blac- cotton

soil and ce$ent

The results of the test shows that the behavior of both cemented and uncemented soils

8Table 5.)0 and Table 5.)59 are significantly influenced by fiber reinforcement. In general

addition of cement to soil increases stiffness, brittleness and peak strength and further

addition of fiber increases both the peak and residual strength, decreases stiffness, and

changes the cemented brittle behavior to a more ductile one. This can be better understood in

Stress vs Strain relationship.

Table 5.1> @** 6al!es and +@C 6al!es for Blac- Cotton Soil 8ith 6ario!s

Percenta%e of Ce$ent = PP

Sl.) S+( @** :%cc; +@C :0;

)&! Soil < )= !ement <

2.15= 776).01 1).5?

1&! Soil < 1= !ement <

2.52= 776).0/ 1).>1

/&! Soil < /= !ement <

2.05= 776).( )A./?

>&! Soil < >= !ement < )=

776).0( )(.A?

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Ce$ent = PP.

5.&.".3Effect of PP on co$paction characteristics of BC soil RB941

Here also same observation can be made, addition of %&I'() to soil increases

stiffness, brittleness and peak strength and further addition of fiber increases both the peak

and residual strength, decreases stiffness, and changes the cemented brittle behavior to a more

ductile one.

Table 5.14 @** 6al!es and +@C 6al!es for Blac- Cotton Soil 8ith 6ario!sPercenta%e of RB = PP

Sl.) S+( @** :%cc; +@C :0;

) &! Soil < )= %&I < 2.15= 776 ).?A 12.((

1 &! Soil < 1= %&I < 2.52= 776 ).0 1).//

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/ &! Soil < /= %&I < 2.05= 776 ).() )(.?

> &! Soil < >= %&I < )= 776 ).0( )A

i%95.1> @** and +@C for Blac- Cotton Soil 8ith 6ario!s Percenta%e of

RB PP.

5.&.".>Effect of rando$l/ distrib!ted discrete coir fiber on co$paction characteristics of

BC soil

+ptimum moisture content of soil increases by increase in percentage of randomly

distributed discrete coir fiber. It is due to the volume of soil is replaced by absorptive

chemosphere of dry coir fiber. "s the percentage of coir fiber increases the #** values of

soil increases up to 2./percent and then reduces on further addition of coir fiber, this may be

partly due to the resistance offered by the adhesion between the soil and coir surface and

partly by the friction between the soil grains, Fith further increase in coir content, the soil'

fiber adhesion and frictional resistance of soil grains decreases due to the increased water

content in the soil'coir matri resulting in decrease in the #** value further it is due to the

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volume of soil replaced by the low density of coir fiber. Similar conclusions were drawn by

8lekha et al9. one of the main advantages of using randomly distributed fiber is the

maintenance of strength isotropy and absence of potential planes of weakness that can

develop parallel to the oriented reinforcement unlike geotetiles or geomembranes.

The main advantages of coir fibers compared to other natural fibers are its high initial

strength, stiffness, and hydraulic properties. If the requirement is for a shorter period, then

coir is the best choice due its biodegradability compared to synthetic fibers. If it has to be

used for longer period, then chemical treatment and polymer coating will improve the life of

the coir product. Hence, we propose to conduct tests to quantify the improvement in

engineering properties of epansive soil due to the addition of coir fibers. Table 5.)A shows

the compaction test results, on addition of coir to the &! soil, maimum dry density increases

up to 2./percent and then reduces on further addition of coir fiberN this may be partly due to

the resistance offered by the adhesion between the soil and coir surface and partly by the

friction between the soil grains. Fith further increase in coir content, the soil'coir adhesion

and frictional resistance of soil grains decreases due to the increased water content in the soil'

coir matri resulting in decrease in the #** value.

Table 5.1? @** and +@C 6al!es for Blac- Cotton Soil 8ith 6ario!s Percenta%e of

Coir fiber.

Sl.2 S+I4 #** 8gcc9 +#! 8=9

) &! Soil "lone < 2.1= !+I% 6I&$% ).0> )(.>1

1 &&! Soil "lone < 2./= !+I% 6I&$% ).00 )(.(/

/ &! Soil "lone < 2.>= !+I% 6I&$% ).02 )(.A/

> &! Soil "lone < 2.5= !+I% 6I&$% ).?A )A.05

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i% 5.14 @** and +@C for Blac- Cotton Soil 8ith 6ario!s Percenta%e of Coir fiber

5.&.".4Effect of (i$e on co$paction characteristics of BC soil

The main benefits of using lime to stabilize clays are improved workability and

volume stability I%! S7 12213 if the plasticity of soil is high there usually sufficient clay

minerals which can be readily stabilized by lime. In such cases cement is more difficult to

mi intimately with plastic material I%! S7 (A'12)23. workability is improved because

flocculation makes the clay more friable this assists combination for effective miing and

compaction. The compaction curve for lime treated clay is generally flatter, which makes

moisture control less critical and reduces the variability of density produced K" adagouda

et al3 the compaction test results presented in table 5.1 and fig 5.)A reveals the same

agreement with above discussions, the maimum dry density of soil alone is )?.0knm/ on

addition of 1= lime marginally increases the #** of &! soil to )?.( knm/. 6urther #**

increases marginally to )?.A knm/ as the lime content is increased to another 1= , the

maimum dry density is equal to )?.A= knm/ after adding another 1= lime then the #**

reduces to )?.( knm/ for (= lime addition. 6rom the above results the optimum lime content

can be fied in between / to >= therefore addition of lime did not improve much on the

compaction characteristics of the soil under investigation.

6rom the test results shown in the Table5.12 and 6ig 5.)A, it is observed that there is

not much variation in maimum dry density with addition of lime when compared with &!

soil alone but optimum moisture content decreased with the addition of lime.

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Table 5." @** 6al!es and +@C 6al!es for Blac- Cotton Soil 8ith 6ario!s

Percenta%e of (i$e

Sl.2 S+I4 #**8gcc9

+#! 8=9

) &! Soil "lone < 1= 4I#$ ).?( )?.)A

1 &! Soil "lone < >= 4I#$ ).?A )?.A0

/ &! Soil "lone < ?= 4I#$ ).?A )?./5

> &! Soil "lone < (= 4I#$ ).?( )5.5A

i% 5.1? @** and +@C for Blac- Cotton Soil 8ith 6ario!s Percenta%e of (i$e

5.&.".?Effect of l/ ash on co$paction characteristics of BC soil

The compaction tests were performed on the &! soil and soil'flyash miture

immediately after the preparation of soil fly ash miture in accordance with the specification

to study the effect of fly ash on the compaction characteristics. The maimum dry density and

the optimum moisture content values obtained by conducting these tests soil treated with

different percentages of fly ash are shown in Table5.1) and figure 5.12. +n addition of fly ash

to &lock cotton soil, maimum dry density increases up to 12= and then reduces on further

addition of fly ash. This may be due to decrease in repulsive pressure of soil, which resists

compactive effort. !onsequently soil becomes closer in spite of lower specific gravity theincrease is observed. Thus the decrease in the void ratio would be much more reflected in the

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increase in the maimum dry density. The optimum moisture content has reduced from

)0.(0= to)0=. Fith decrease in repulsive pressure and due to addition of flyash with lower

water adsorption capacity, the optimum moisture content of the miture decreases.

Table 5."1 @** 6al!es and +@C 6al!es for Blac- Cotton Soil 8ith 6ario!s

Percenta%e of l/ash

Sl.2 S+I4 #** 8gcc9 +#! 8=9

) &! Soil "lone < )2= 64O"SH ).0/0 )0.(0

1 &! Soil "lone < 12= 64O"SH ).0A? )0.>/

/ &! Soil "lone < /2= 64O"SH ).0?5 )0.2(

i%95." @** and +@C for Blac- Cotton Soil 8ith 6ario!s Percenta%e of

l/ash

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5.&.".1Effect of Coir fiber on co$paction characteristics of li$e stabilised BC soil

&y providing fiber reinforcement to the soil'lime mi the maimum dry density increases to

).0? gcc from ).?A gcc as presented in Table 5.12 and Table 5.11 this shows that the

behavior of both lime treated and untreated soils are significantly influenced by fiber

reinforcement. In general addition of lime to soil increases stiffness, brittleness and peak

strength and further addition of fiber increases both the peak and residual strength, decreases

stiffness, and changes the brittle behavior to a more ductile one. This can be better understood

in Stress vs Strain relationship.

Table 5."" @** 6al!es and +@C 6al!es for Blac- Cotton Soil 8ith 6ario!s

Percenta%e of Coir fiber (i$e

Sl.2 S+I4#**

8gcc9

+#!

8=9

) &! Soil "lone < 2.)= !+I% 6I&$% < )= 4I#$ ).0) )(.1)

1 &! Soil "lone < 2.)5= !+I% 6I&$% < 1= 4I#$ ).0? )(.0/

/ &! Soil "lone < 2.1= !+I% 6I&$% < /= 4I#$ ).01 )A.1/

> &! Soil "lone < 2.15= !+I% 6I&$% < >= 4I#$ ).?A )A.05

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i%95."1 @** and +@C for Blac- Cotton Soil 8ith 6ario!s Percenta%e of

Coir fiber (i$e

5.&.".11Effect of Coir fiber on co$paction characteristics of BC soil and l/ ash

&y coir fiber reinforcement to the soil'fly ash mi it is observed that #aimum dry

density increases to ).()gcc from ).0?gcc as shown in Table 5.1) and Table 5.1/,this clearly

shows that the behavior of fly ash treated soil and untreated soil are significantly influenced

by fiber inclusion.

Table 5."& @** 6al!es and +@C 6al!es for Blac- Cotton Soil 8ith 6ario!s

Percenta%e of Coir fiber l/ash

Sl.2 S+I4#**

8gcc9

+#!

8=9

) &! Soil "lone < 2.)= !+I% 6I&$% < 5= 64O"SH ).0? )0.1/

1 &! Soil "lone < 2.)5= !+I% 6I&$% < )2= 64O"SH ).0( )?.A0

/ &! Soil "lone < 2.1= !+I% 6I&$% < )5= 64O"SH ).() )?.1/

> &! Soil "lone < 2.15= !+I% 6I&$% < 12= 64O"SH ).00 )?.2)

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i%95."" @** and +@C for Blac- Cotton Soil 8ith 6ario!s Percenta%e of Coir

fiber l/ash

5.&.".1"Effect of l/ ash on co$paction characteristics of BC soil li$e

In this study the maimum dry density reaches up to ).0Agcc at a proportion of

1=limeB)2=flyashB((=&! soil and then reduces on further addition of lime and fly

ash, This may be due to decrease in repulsive pressure of soil, which resists

compactive effort. !onsequently soil becomes closer in spite of lower specific gravity

the increase is observed. Thus the decrease in the void ratio would be much more

reflected in the increase in the maimum dry density

Table 5."2 @** 6al!es and +@C 6al!es for Blac- Cotton Soil 8ith 6ario!s

Percenta%e of l/ash = (i$e

Sl.2 S+I4 #** 8gcc9 +#! 8=9

) &! Soil "lone < )= 4I#$ < 64O"SH 5= ).0? )?.>/

1&! Soil "lone < 1= 4I#$ < 64O"SH

)2=).0A )?.0(

/

&! Soil "lone < /= 4I#$ < 64O"SH

)5= ).00 )?.5?

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>&! Soil "lone < >= 4I#$ < 64O"SH

12=).0/ )?.//

i%95."& @** and +@C for Blac- Cotton Soil 8ith 6ario!s Percenta%es of l/ash (i$e

5.&.& Stren%th properties of blac- cotton soil treated 8ith ce$ent and other additives

The strength properties of black cotton soil treated with various percentages of

!ement and other additives have been studied. The strength of the soil depends on density

and compactive effort.

5.&.&.1Effect of Ce$ent on Blac- cotton soil

nconfined compression strength tests were conducted on compacted specimens with

varying cement contents and cured for /,0,)> and 1( days, at the end of each curing period. It

has been observed that at higher curing periods and at higher cement content there is

significant increase in strength ie from /)2 kn/m2 for zero day to )A/> kn/m2 for 1( days

curing. This is because during the process which led to greater hydration opportunities ie

longer curing periods resulted in relatively large increase in strength. 6rom table 5.15 we can

observe the interaction between the curing and cement content, the significance of this

interaction shows that the increase in compressive strength is not solely due to the period of

moist curing but depends to a significant degree on the cement content used in this work. It

can be seen from figure 5.1>

That the strength increased with increasing curing period but this was more in specimens

containing ( percent cement than those containing 1,>,? percent cement by dry weight of soil.

Thus the advantage of increase in strength with period of curing is not fully unless adequate

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quantity of cement is present, addition of cement however is generally limited by the

economics of the pro-ect and also by considerations of severe shrinkage crack.

Table 5."5 'nconfined Co$pressive Stren%th 6al!es for Ce$ent stabilized soil sa$ple

i% 5."2 Effect of C!rin% period on 'CS for 6ario!s Percenta%es of Ce$ent

5.&.&."Effect of RB941 on Blac- cotton soil

Ce$ent

Percenta%e

'nconfined Co$pressive Stren%th

$$ediate &9*a/s >9*a/s 129*a/s "49*a/s

" )1? 1A> /1A />? >>(

2 1>? ?1( 05( A(/ )250

3 1>A (02 A?2 )1A? )>?2

4 /)2 )11A )55( )0A) )A/>

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Table 5."3 'nconfined Co$pressive Stren%th of RB941 stabilized soil sa$ple

i% 5."5 Effect of C!rin% period on 'CS for 6ario!s Percenta%e of RB941

5.&

.&.&

Eff

ect

of

PP on Blac- cotton soil

The stress strain curves obtained in !! tests are given in figure for the unreinforced

samples and for the fiber reinforced ones. It is readily observed from figure that the overall

soil behavior is significantly influenced by the investigated variables. 4ike peak strength,

RB941

Percenta%e

'nconfined Co$pressive Stren%th :Pa;

$$ediate &9*a/s >9*a/s 129*a/s "49*a/s

" )>2 1() /12 /(0 >>/

2 )() >(( 5A0 ?AA A)0

3 )A> 5AA 0(? A1> )1))

4 1/5 A20 )/52 )5?( )011

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stiffness, brittleness and residual response changed as a consequence of either the separate or

the -oined effects of fiber and soil. The general pattern can be better observed from

compaction curves, the most impressive advantage of fiber reinforcement when applied to

clay soil is the remarkable improvement of ductility of the material at optimum moisture

content and even at the dry of optimum, which is very significant since the volumetric

response lies between those observed for non reinforced specimen and reinforced specimen.

This response can be observed from compaction curves.

Table 5."> 'nconfined Co$pressive Stren%th of PP stabilized soil sa$ple

Partic!lars 'CS Test 6al!es:Pa;

&! S+I4 < 2.5=

7olypropylene

6ibers

152.63

&! S+I4 < ).2=

7olypropylene 6ibers 161.93

&! S+I4 < ).5=


&! S+I4 < 1.2=


&! S+I4 < 1.5=


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i%95."3 'nconfined Co$pressive Stren%th of Blac- Cotton Soil Treated

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i% 5."> Effect of C!rin% period on 'CS for 6ario!s Percenta%e of Ce$ent=RB941

5.&.&.2Effect of ce$ent and PP on blac- cotton soil

Table 5."? 'nconfined co$pressive stren%th of ce$entPP stabilized soil sa$ple

Ce$ent =PP

Percenta%e


$$ediate &9*a/s >9*a/s 129*a/s "49*a/s

)= < 2.15= )/A 1?A /// /(1 >?/

1= < 2.52= )A0 >2> ?21 (/) A>?

/= < 2.05= 1/1 ?)1 (>) ))1/ )//1

>= < )= 1>? A/> )>>> )?A0 )A/(

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i% 5."4 Effect of C!rin% period on 'CS for 6ario!s Percenta%e of Ce$ent=PP

5.&.&.5 Effect of RB941 and PP on blac- cotton soil

Table 5.& 'nconfined co$pressive stren%th of RBPP stabilized soil sa$ple

RB =PP

Percenta%e


$$ediate &9*a/s >9*a/s 129*a/s "49*a/s

)= < 2.15= )15 1>1 />) /0( >)1

1= < 2.52= )0? /(/ 5() 0A? A2>

/= < 2.05= 12> 5(? (/> )2(/ )1A1

>= < )= 115 (?> )>>( )??> )(??

i% 5."? Effect of C!rin% period on 'CS for 6ario!s Percenta%e of RB=PP

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5.&.&.3 Effect of coir fiber on blac- cotton soil

" typical variation of unconfined compressive strength with curing period is presented in

fig5./2. It has been observed that addition of coir fiber with aspect ratio five hundred have

shown significant increase in the unconfined compressive strength with curing period.

6igure 5./2 shows stress'strain behavior of all composite specimens. It can be seen that the

&! soil reinforced with coir fiber will increase its strain carrying capacity after post peak

strength. The increase in strength of bc soil reinforced with fiber is quite predictable since the

technique primarily involves the introduction of primary material in a weak soil and it is in

accordance with the observation of 7orbha etal 8122)9 and Jinod etal 812209.

The optimum fiber content of fiber reinforced &! soil determined by unconfined compressive

strength result tested immediately as presented in table 5./) was 2./percent. however the

unconfined compressive strength value increases with increase in percentage of coir fiber and

curing days.

Table 5.&1 'nconfined co$pressive stren%th val!es for coir fiber stabilized soil sa$ple

BC S+( = C+R

BRE 0


$$ediate &9*a/s >9*a/s 129*a/s "49*a/s

2.1= )?>.1) )?( 11> 1(( /1>

2./= )A(.>> 1(> >(> 5A? ?5(

2.>= )//.?) /?? ?>1 (/? A/1

2.5= ))( //2 >2(.A( (/2.55 ))(2.(0

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i% 5.& 'nconfined co$pressive stren%th of blac- cotton soil treated 8ith vario!s

Percenta%es of coir fibers

5.&.&.3 Effect of li$e on blac- cotton soilThe unconfined compressive strength of black cotton soil treated with various percentage of

lime up to 1( days of curing has been studied. The unconfined strength values for various

percentages of lime for different curing period are shown in table 5./1. as seen from the

fig5./), the strength of black cotton soil increases with 1= of lime both on immediate testing

and with curing, with the further addition of lime the strength of black cotton soil increases.

Increase in strength of black cotton soil with increase in percentage of lime has been

attributed to the formation of calcium silicate, hydrates and aluminates by reaction of black

cotton soil silica and alumina with calcium.

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Table 5.&" 'nconfined Co$pressive Stren%th of (i$e stabilized soil sa$ple

(@E 0


$$ediate &9*a/s >9*a/s 129*a/s "49*a/s

1= )?1.?/ )01.)/ 151./1 /)5.)5 /A(.?(

>= )(0.1> 1)/.>5 5)2.1/ ?2A.A( ??/.0?

?= )0?.5A /01.5> ?5/.)> (>5.A( A/A.?(

(= )?5.) >/).2? 0/1.0( )2A2.A( )10(.5>

i% 5.&1 Effect of C!rin% period on 'CS for 6ario!s Percenta%e of (i$e

5.&.&.> Effect of l/ ash on Blac- cotton soil

The unconfined compressive strength of black cotton soil increases up to 12= addition of

flyash beyond 12= addition the unconfined compressive strength decreases. The unconfined

compressive strength of 12= addition of flyash is (5.?5knm/ when tested immediately

which is less than unconfined compressive strength of bc soil alone. The !S of blackcotton

soil alone is )2>knm/,after three days of curing it can be observed that the strength of black

cotton soil and flyash is )25.?>knm/ which is little higher than black cotton soil alone.

further after 1(days of curing it can be observed that the strength of black cotton soil and

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12= by weight of flyash is />5knm1, the strength increase is almost three times the black

cotton soil, figure 5./1 shows clearly the increase of strength of black cotton soil and flyash

mitures. Thus the improvement in the strength of black cotton soil by flyash is due to the

hydration of its cementitious phases.

Table 5.&& 'CS Test val!es for Blac- Cotton Soil 8ith l/ash

BC S+( =

(ASH0


$$ediate &9*a/s >9*a/s 129*a/s "49*a/s

)2= 05.)( A(.?/ )2A.>5 1)5.5( 1A(.0?

12= (5.?5 )25.?> )(A.5/ 10(.A( />5.?5

/2= 00./> )2).?5 ))/.?5 11).>5 /)5.>5

Table 5.&" 'nconfined Co$pressive Stren%th of l/ash stabilized soil sa$ple

5.&.&.4 Effect of Coir on li$e stabilized blac- cotton soil

Table 5.&2 'nconfined co$pressive stren%th of coir fibre (i$e stabilized soil sa$ple

(@E=C+R

BRE 0


$$ediate &9*a/s >9*a/s 129*a/s "49*a/s

)= < 2.)= )1/./1 )?(.2A 11>.)1 /2( /?0.>?

1= < 2.)5= )?).>> 1(>.)) >(>.>/ ?)?.0? ?5(.?5

/= < 2.1= )?>.2/ /??./> ?>1.)1 ((A.5> A/1.(0

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>= < 2.15= )A(.(/ >11.1) 01>.A ))/2.0? )1(A.2A

i% 5.&& Effect of C!rin% period on 'CS for 6ario!s Percenta%e of Coir fiber = (i$e

5.&.&.? Effect of coir on fl/ ash stabilized blac- cotton soil

Table 5.&5 'nconfined co$pressive stren%th of coir fiber fl/ash stabilized soil sa$ple

C+R BRE0 =

(ASH0


$$ediate &9*a/s >9*a/s 129*a/s "49*a/s

2.)= < 5= )2/./? )?(./ 11>.)1 1((.>5 /1>./1

2.)5= < )2= )51.1) 1(>.20 >(>.A( 5A?.11 ?1/.(A

2.1= < )5= )A(.?/ /)2.)1 ?>1.5? A(?.5A )22/.0?

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2.15= < 12= )5(.?) /52./1 0)2.?0 ))12 )1)2.>/

i% 5.&2 Effect of C!rin% period on 'CS for 6ario!s Percenta%e of Coir fiber = l/ash

5.&.&.1 Effect of l/ ash and li$e on Blac- cotton soil

Table 5.&3 'nconfined co$pressive stren%th of li$e fl/ash stabilized soil sa$ple

(@E = (ASH

0


$$ediate &9*a/s >9*a/s 129*a/s "49*a/s

)= < 5= 1)2.)/ /0(.?5 >?0.51 5A0.1/ 01/.>5

1= < )2= 1/1.20 >)5./> 5?0.(/ ?A(.>5 ()/.?>

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/= < )5= 110.(/ >20.(A 5>5./0 ?0/.A1 0A?.>)

>= < 12= 1)(.)A /((.?5 >A(.5> ?/2.>5 0/5.>5

i% 5.&5 Effect of C!rin% period on 'CS for 6ario!s Percenta%e of (i$e = l/ash.

5.1 Blac- cotton soil

• "fter conducting the physical properties test on &lack !otton Soil it is found that

4iquid 4imit is >5.02 and 7lastic 4imit of Soil is 11.)>. Hence treating it as medium

clayey soil.

• The #** and +#! of &lack !otton Soil are )?./( Km/ and 12.2(=, for this

+#! ; #** the value of !&% was found to be /.22=

• 6rom the test conducted it can be observed that, the !S parameters of the &! soil

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alone is )2>.2? Km/

• 6rom the present investigation it is found that the !o'efficient of $lastic niform

!ompression is /)//2 Km/ for &! soil alone.

• 6rom the present investigation it is found that the #odulus of subgrade reaction is

(.22 Km/ for &! soil alone.

• 6rom the present investigation it is found that the #odulus of elasticity is found to be

??01.?? Km1 for &! soil alone.

5." CE@E)T

• ). "fter conducting the physical properties test on &lack !otton Soil < !ement, it is

found that 4iquid 4imit is >>.A2 and 7lastic 4imit of Soil is 1>.)?.

• 1. The #** and +#! of &lack !otton Soil are )0.5? Km/ and 11.)(=

• /. The !S parameters of the soil increases upto (= of !ement and further decreases

with increase in percentage of !ement. "nd mode of failure changing from brittle to

ductile.

• >. !alifornia &earing %atio of the soil increases upto (= of !ement and further

decreases with increase in percentage of !ement.

• 5. It is found that the value of !&% increases ?0.A5= with the addition of cement to

the &! soil compare with &! soil alone.

• ?. 6rom the present investigation it is found that the !o'efficient of $lastic niform

!ompression is 5?222 Km/ in case of !ement.

• 0. It is found that the value of !u increases >>.)2= with the addition of !ement to the

&! soil when compare with the &! soil alone.

• (. 6rom the present investigation it is found that the #odulus of subgrade reaction is

)1.22 Km/ for &! soil < !ement

• A. 6rom the present investigation it is found that the #odulus of elasticity is found to

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be )222(.AA Km1 for &! soil < !ement.

5.& R+A* B'(*)G )TER)AT+)A( GRA*E 9 41

• "fter conducting the physical properties test on &lack !otton Soil < %&I, it is found

that 4iquid 4imit is >>.?2 and 7lastic 4imit of Soil is 1/.A2.

• The #** and +#! of &lack !otton Soil are )0./? Km/ and 1/.>?=

• 6rom the test conducted it can be observed that, the !S parameters of the soil

increases upto (= of %&I and further decreases with increase in percentage of %&I.

• !alifornia &earing %atio of the soil increases upto (= of %&I and further decreases

with increase in percentage of %&I.

• It is found that the value of !&% increases >)./5= with the addition of %&I to the

&! soil compare with &! soil alone.

• It is found that the !o'efficient of $lastic niform !ompression is 5//>2 Km/ in

case of %&I.

• It is found that the value of !u increases >).1?= with the addition of %&I to the &!

soil when compare with the &! soil alone.


(.>2 Km/ for &! soil

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• !&% of the soil increases upto 1= of polypropylene fibers ; further decreases with

increase in percentage of 7olypropylene 6ibers.

• It is found that the value of !&% increases 10.1A= with the addition of 776 to the

&! soil compare with &! soil alone.


!ompression is /A212 Km/.

• It is found that the value of !u increases )A.0>= with the addition of 776 to the &!

soil when compare with the &! soil alone.


12.(2 Km/ for &! soil < 776.


)0/>(.A1 Km1 for &! soil < 776.

5.5 CE@E)T and RB

• "fter conducting the physical properties test on &lack !otton Soil < !ement < %&I, it

is found that 4iquid 4imit is >>.0> and 7lastic 4imit of Soil is 1>.2)

• The #** and +#! of &lack !otton Soil are )0.0> Km/ and 11.0?=.

• 6rom the test conducted it can be observed that, the !S parameters of the soil

increases upto >= of !ement < >= of %&I and further decreases with increase in

percentage of !ement < %&I.

• !alifornia &earing %atio of the soil increases upto >= of !ement < >= of %&I and

further decreases with increase in percentage of !ement < %&I.

• It is found that the value of !&% increases ?/.52= with the addition of cement < %&I

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to the &! soil compare with &! soil alone.


!ompression is higher 8!u ' >()12 Km/9 in case of !ement < %&I.

• It is found that the value of !u increases />.A1= with the addition of !ement < %&I

to the &! soil when compare with the &! soil alone.


A.?2 Km/ for &! soil < !$#$T < %&I.


(220.)A Km1 for &! soil < !$#$T < %&I.

5.3 CE@E)T and PP

• "fter conducting the physical properties test on &lack !otton Soil < !ement < 776, it

is found that 4iquid 4imit is >>.?1 and 7lastic 4imit of Soil is 11.?>.

• The #** and +#! of &lack !otton Soil are )0.?? Km/ and )A./?=.

• The !S parameters of the soil increases upto >= of !ement < )= of 776 and

further decreases with increase in percentage of %&I.

• !alifornia &earing %atio of the soil increases upto >= of !ement < )= of 776 and

further decreases with increase in percentage of !ement < 776.

• It is found that the value of !&% increases ?2.>2= with the addition of cement < 776

to the &! soil compare with &! soil alone.


!ompression is /0052 Km/ in case of !ement < 776 than when compare to &! soil

alone.

• It is found that the value of !u increases )?.A0= with the addition of !ement < 776

to the &! soil when compare with the &! soil alone.


)).?2 Km/ for &! soil < !$#$T < 776.


A?05./? Km1 for &! soil < !$#$T < 776.

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5.> RB and PP

• "fter conducting the physical properties test on &! Soil < %&I < 776, it is found that

4iquid 4imit is >>./> and 7lastic 4imit of Soil is 1/.(1

• The #** and +#! of &lack !otton Soil are )0.05 Km/ and )(.?2=

• The +#! of the soil increases with the increase in the percentage of %&I < 776 and

#** decreases with increase in percentage %&I < 776.

• The +#! of &lack !otton Soil increases with increased percentage of %&I < 776

because of increase in the surface area due to addition of fibers to the soil.

• The !S parameters of the soil increases upto >= of %&I< )= 776 and further

decreases with increase in percentage of %&I < 776.

• !&% of the soil increases upto >= of %&I < )= of 776 and further decreases with

increase in percentage of %oad building international < 7olypropylene 6ibers.

• It is found that the value of !&% increases >2.11= with the addition of %&I < 776 to

the &! soil compare with &! soil alone.


!ompression is very high 8!u ' 52>/2 Km/9 in case of %&I < 776.

• It is found that the value of !u increases /0.(A= with the addition of %&I < 776 to

the &! soil when compared with the &! soil alone.


)2.(2 Km/ for &! soil < %&I < 776.


A22(.2A Km1 for &! soil < %&I < 776.

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C+)C('S+)S

The results of the laboratory investigation indicated that the inclusion of fibers in the

soils improved the unconfined compressive strength.

Effect of pol/prop/lene on co$paction characteristics

• The effect of addition of polypropylene to black cotton soil on maimum dry density

and optimum moisture content depends upon the changes in strength Pfabric repulsive

force. Thus the transition at which decrease or increase of maimum dry density with

change in optimum moisture content in a particular soil miture depends upon the

changes in strength'fabric and repulsive forces

• !ement was used as a chemical agent > percent cement content with respect to weight

of soil ) percent polypropylene fiber content was observed to give maimum

compressive strength of )A/(knm for 1(days.

• Fhen soil was combined only with cement, without using fiber, ( percent cement

content was observed to give maimum compressive strength of )A/>knm for

1(days.

• Fith the use of polypropylene fiber to cemented soil it was observed that there is

increase in the compressive strength and mode of failure changes from brittle to

ductile.

• The strain required to mobilise peak strength is more in case of fiber reinforced

specimen than when compared to unreinforced specimen.

• The soaked !&% of the soil treated with 1 percent cement alone increased to 0.50

percent from >.5? percent on addition of 2.5 percent polypropylene fiber tested for

zero days curing.

• The addition of cement increases the !! and soaked !&% of the epansive soil.

6urther with the addition of polypropylene fiber to cement stabilized epansive soil

the !! and soaked !&% increases up to ?2 percent.

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• 7olypropylene fibers resist the shrinkage cracks that will appear when cement was

used as stabilizer.

• The strength gained by black cotton soil when stabilized with ( percent cement is

even less than the strength gained by adding ) percent polypropylene fiber with >

percent cement to the same soil.

• In the case of %&I

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