UNCONFINED COMPRESSIVE STRENGTH OF STABILIZED SOIL · estimated by conducting unconfined compression test, Where astriaxial compression test, are used very rarely further the undrained

International Journal of Emerging Technology in Computer Science & Electronics (IJETCSE)

ISSN: 0976-1353 Volume 21 Issue 3 – APRIL 2016.

583

UNCONFINED COMPRESSIVE STRENGTH OF

STABILIZED SOIL K. Saranya M.E*Asst.prof .,Panimalar Engineering College.,Chennai,India

Deepak.V**.,Muniyandi.S**.,Balaji.S**.,Arunkumar.M**

B.E (Final Year Students)Panimalar Engineering College, Chennai.,

Abstract -Improvement of soft soils by deep mixing is gaining

popularity in many countries. Among the various stabilizers

available for stabilization of soft soil by deep mixing, lime and

lime-cement have been used for several decades. In recent

years fly ash, Which is a waste product from the thermal

power stations is also utilized for improving the engineering

properties of soils. The strength of stabilized soils is generally

estimated by conducting unconfined compression test, Where

astriaxial compression test, are used very rarely further the

undrained strength of stabilized soil is consider for design.

Extensive experimental programme is carried out to evaluate

the unconfined compressive strength of stabilized soft soil. The

various stabilizers proposed to be used are lime alone

(3%,5%,7%), cement alone(1.5%,3%,5%), fly ash alone

(10%,15%,20%) and glass powder (5%,10%,15%), cement-

glass powder mixer. UCC strength was obtained for soil was

treated with cement alone (1.5%,3%,5%),lime alone

(3%,5%,7%), Fly ash (10%,15%,20%), Glass powder

(5%,10%,15%) and combination of cement glass powder

(1.5%+5%, 3%+10% , 5%+15%) and cured for 2,7 and 14

days. In general it is noticed that the UCC strength increases

with increase in the percentage of stabilizer curing period.

Index Terms: Flyash, undrained strength, Glass powder, UCC

Strength

I.INTRODUCTION

Soil stabilization, in a broad sense, incorporates, the

various methods employed for modifying the properties of a

soil to improve its engineering performance. Stabilization is

being used for a variety of engineering works, where the

main objective is to increase the strength or stability of soil

and to reduce the construction cost by making best use of

the locally available materials.

Methods of stabilization may be grouped under two main

types,

1. Modification or improvement of a soil property of the

existing soil without any admixture.

2. Modification of the properties with the help of

admixtures.

The properties of soft soils can be improved by either of the

above mentioned methods.

II.MATERIALS

SOIL

Locally available expansive soil has been used for the

experimental investigation. Soil sample collected from the

local area (kelambakkam)

Chennai at a depth of 0.5 – 1.0 m was used in the present

study. To characterize the soil various experiments were

conducted as per BIS specification.

parameter Symbol or

percentage

Values

Specific

gravity

Gs 2.33

Clay % 80

Silt % 12

Sand % 8

Liquid limit % 58

Plastic limit % 34

Plasticity

index

% 24

Shrinkage

limit

% 61.71

Dry density g/cc 1.7

IS

Classification

CH Clay of

high

plasticity



584

FLY ASH

Fly ash collected from “ENNORE” thermal power station

was used for stabilization.

LIME

Laboratory grade hydrated lime was used for stabilization of

soil.

CEMENT

Commercially available Portland cement was used in

the present investigation.

GLASS POWDER

It is commercially available material from grinding of glass

pieces.

III.EXPERIMENTAL PROCEDURE

UNCONFINED COMPRESSIVE STRENGTH

Strength is an important engineering behavior based on

which foundations are designed. In order to determine the

strength unconfined test was performed. Unconfined

compression test is simple test which is useful for the

evaluation of suitable quantities and compositions of

stabilizers

Unconfined Compression Testing Machine

PREPARATION OF SAMPLE

Samples are prepared by taking appropriate amount of

soil passing through 425µm IS sieve & stabilizers such as

Cement, Lime, Fly ash etc. Then water is added to the

required amount. The sample is uniformly mixed and placed

in the mould of height and compacted. Then the sample is

removed from the mould and

kept for curing in “air tight bag” for 2, 7 and 14 days.

Preparation of sample

CURING PROCEDURE

The sample is cured for 2, 7 and 14 days in an air tight bag.

Chemical

Composition

Percentage

SiO 2 56.77

AI20 3 31.83

Fe20 3 2.82

CaO 0.78

K 2 0 1.96

Ti02 2.77

Na0 0.68

MgO 2.39



585

Curing procedure

RESULTS AND DISCUSSIONS

Fig 1 Stress strain curve of stabilized soil with 1.5%

cement

Fig 1 plots the stress strain curve of the stabilized soil with

1.5% cement. It is observed that irrespective of increase in

curing periods the stress becomes asymmetric to strain and

exhibits less compressive strength when compared to other

percentages

Fig 2 below stress-strain relationship of stabilized soil with

3% cement is shown in Fig 2 The stress-strain curve shows

the pronounced peak as the curing periods favors the soil-

cement reaction to complete and achieve maximum

compressive strength

Fig 2 Stress strain curve of stabilized soil with 3%

cement

Curing periods

Lime

alone

%

Cement alone

%

Fly ash alone

%

Glass powder

alone

%

Cement +

glass powder

%

0

3

5

7

1.5

3

5

10

15

20

5

10

15

1.5+5

3+10

5+15

2

3

5

7

1.5

3

5

10

15

20

5

10

15

1.5+5

3+10

5+15

7

3

5

7

1.5

3

5

10

15

20

5

10

15

1.5+5

3+10

5+15

14

3

5

7

1.5

3

5

10

15

20

5

10

15

1.5+5

3+10

5+15



586

Fig 3 Stress strain curve of stabilized soil with 5% cement

Fig 3 the stress strain relationship of stabilized soil with 5%

cement cured for 2, 7 & 14 days. The sample cured for 2

days showed a plastic behavior, that is the stress between

almost constant with increase in strain for that of 5% cement

content. Hence increase in curing of samples 7, 14 days

showed increase in strength.

Table.1 UCC strength of cured cement stabilized soil of

(1.5, 3 and 5%)

Table 1 summarizes the strength of UCC stabilized soil with

1.5%, 3% and 5% cement content cured for 2, 7 and 14

days. Data presented in the table 4.1 brings out that the UCC

strength of soil increased with increase in cement content

and as well, as increase in curing periods. When compared

to 1.5% and 3% of cement content strength is increases with

curing periods. But compared to 1.5% and 5% of cement

content strength is much more effective.

Fig 4 Variation of UCC strength with curing periods and

cement content

Fig 4 shows strength ratio of stabilized soil with 1.5%, 3%

and 5% cement content cured for 2, 7 and 14 days. The

strength of 5% cement is almost 1.4 to 3.5 times the strength

of 1.5% cement treated soil for various curing periods.

The increase in the strength for the soil treated with 1.5%,

3% and 5% of cement is 1.6 to 1.8 times for change in

curing period from 2 to 7 days curing. After 14 days curing

the strength is increased to nearly 1.8 to 2.6 times the 2 days

curing the strength for all cement contents.

Fig 5 Stress strain curve of stabilized soil with 3% lime

Fig 4.5 plots the stress strain curve of the stabilized soil with

3% lime. It is observed that the irrespective of increase in



percentages.

Curing periods

( days)

UCC strength (kPa)

1.5% Cement

3% Cement

5% Cement

0 71.61 79.5 88.3

2 76.51 87.3 103

7 83.38 108 147

14 94.17 118 177



587


5% lime is shown in Fig 6. The stress-strain curve shows

the pronounced peak as the curing period increases. This is

due to the fact that, increase in curing period. Further the

reaction is changed from dispersed to flocculated one. The

sudden failure of specimen indicates the breakage of bond

developed due to soil lime reaction.

Fig 6 Stress strain curve of stabilized soil with 5% lime

Fig 7 plots the stress strain relationship of stabilized soil

with 7% lime cured for 2, 7 and 14 days. The sample cured

for 2 days showed a plastic behavior that is the stress is

almost constant with increase in strain. In case of 7 and 14

day cured samples strength is increased with increase in

stabilizer. Hence curing day increases the same time

strength is also increased.

Fig 7 Stress strain curve of stabilized soil with

7% lime

Curing periods

( days)

UCC strength (kPa)

3% Lime

5% Lime

7% Lime

0 21.58 26.5 30.41

2 43.16 53 62.78

7 68.67 90.3 117.72

14 78.48 128 166.77

Table 2 UCC strength of cured lime stabilized soil of (3, 5 and 7%)

Table 2 summarizes the strength of UCC stabilized soil with

3%, 5% and 7%lime content cured for 2, 7 and 14 days.

Data presented in the table 4.2 brings out that the UCC

strength of soil increased with increase in lime content and

as well, as increase in curing periods. This is due to the

beneficial effects derived from soil- lime reaction. It can be

observed that addition of 3% lime is not much effective in

improving the strength. However, as soon as lime is added

to the soil both modification and stabilization process starts

together and it cannot be said that only after modifying the

plasticity characterization the strength should be improved.

Hence in the present investigation even 5% and 7% lime

addition showed a marginal increase in UCC strength.



588


lime content

Fig 8 shows strength ratio of stabilized soil with 3%, 5% and

7% lime content cured for 2, 7 and 14 days. The strength of

7% lime is almost 1.1 to 1.4 times the strength of 3% lime

treated soil for various curing periods.

The increase in the strength for the soil treated with 3%, 5%

and 7% of lime is 1.1 to 1.4 times for change in curing

period from 2 to 7 days curing. After 14 days curing the

strength is increased to nearly 1.2 to 1.7 times the 2 days

curing the strength for all lime contents.

Fig 9 Stress strain curve of stabilized soil with 10% fly

ash

Fig 9 shows the stress strain curve of the stabilized soil with

10% fly ash. It is observed that irrespective of increase in



stabilizers. When compared from 2 to 14 days of curing with

10% fly ash, stress is increases at the same time strain is

increased.


15% fly ash is shown in Fig 10. The stress strain curve

shows the undrainedstrenth is increases with increase in the

ash content. When compared from 0 to 14 days the strength

is increases corresponding with respect to stress strain curve.


ash


ash

Fig 11 the stress strain relationship of stabilized soil with

20% fly ash cured for 2, 7 and 14 days. The sample cured

for 2 days showed a plastic behavior, that is the stress

between almost constant with increase in strain for that of

20% fly ash content. Hence increase in curing of samples 7,

14 days showed increase in strength.

Curing

periods

( days)

UCC strength (kPa)

10% Fly

ash

15% Fly

ash

20% Fly

ash

0 26.5 37.3 57.9

2 31.4 43.2 71.6

7 35.3 50 81.4

14 46.1 57.9 98.1

Table 3 UCC strength of cured fly ash stabilized soil of (10,

15 and 20%)

Table 3 summarizes the strength of ucc stabilized soil with

10%, 15% and 20% fly ash content cured for 2, 7 and 14

days. Data presented in the table 4.3 bring out that the UCC

strength of soil increased with increase in fly ash content

and as well, as increase in curing periods. When compared

to 10 and 20% fly ash content the strength is not much

effective in improving the strength parameters. When fly ahs

content increases there is a decrease in the optimum

moisture content and the maximum dry unit weight

increases.



589


fly ash content

Fig 12 summarizes strength ratio of stabilized soil with

10%, 15%, 20% fly ash content cured for 2, 7 and 14 days .

The strength of 20% lime is almost 1.7 to 2.1 times the

strength of 10% cement treated soil for various curing

periods.

The increase in the strength for the soil treated with

10%,15% and 20% of fly ash content1.1 to 1.2 times for

change in curing period from 2 to 7 days curing. After 14

days curing the strength is increased nearly 1.3 to 1.5 times

increases.

Fig 4.13 Stress strain curve of stabilized soil with 5%

glass powder


5% glass powder. It is observed that irrespective of increase

in curing periods the stress becomes asymmetric to strain

and exhibits compressive strength is moderate.

Fig 14 below stress-strain relationship of stabilized soil

with 10% glass powder is shown in Fig 4.14. The stress-

strain curve shows the pronounced peak as the curing

periods favors the soil- glass powder reaction to complete

and achieve very less compressive strength

Fig 14 Stress strain curve of stabilized soil with 10% glass

powder

Fig 15 Stress strain curve of stabilized soil with 15% glass

powder

Fig 15 the stress strain relationship of stabilized soil with

15% glass powder cured for 2, 7 and 14 days. The sample

cured for 2 days the stress is almost constant with increase

in strain for that of 15% glass powder content. Hence

increase in curing of samples 7, 14 days showed increase in

strength.

Curing

periods

( days)

UCC strength (kPa)

5%

Glass

powder

10%

Glass

powder

15%

Glass

powder

0 25 43.2 54

2 32 55.9 64.7

7 37 66.7 75.5

14 48 77.5 92.2

Table 4 UCC strength of cured glass powder stabilized soil

of (5, 10 and 15%)


5%, 10% and 15% glass powder content cured for 2, 7 and

14 days. Data presented in the table 4.4 bring out that the

UCC strength of soil increased with increase in glass

powder content and as well, as increase in curing periods.

However , it can be observed that addition of 5% glass

powder is not much effective in improving the strength ,

when compared to 15%, 20% of glass powder content.



590


glass powder content

Fig 16shows the strength ratio of stabilized soil with 5%,

10% and 15% glass powder content cured for 2, 7 and 14

days . The strength of 15% glass powder is almost 1.9 to 2.2

times the strength of 15% glass powder treated soil for

various curing periods.

The increase in the strength for the soil treated with

5%,10% and 15% of glass powder is 1.1 to 1.2 times for

change in curing period from 2 to 7 days curing. Further

after 14 days curing the strength is increased to nearly 1.4 to

1.5 times the 2 days curing the strength for all glass powder

contents.

Fig 17 Stress strain curve of stabilized soil with 1.5%

cement and 5% glass powder


1.5%+5% cement+ glass powder. It is observed that

irrespective of increase in curing periods the stress becomes

asymmetric to strain and exhibits less compressive strength

when compared to other percentages.

Fig 18 below stress-strain relationship of stabilized soil

with 3%+10% cement+ glass powder is shown in Fig 4.18 .

the stress-strain curve shows the pronounced peak as the

curing periods favors the soil- cement+ glass powder

reaction to complete and achieve maximum compressive

strength





Fig 19, The stress strain relationship of stabilized soil with

5%+15% ,cement+ glass powder cured for 2, 7 and 14 days.

The sample cured for 2 days showed a plastic behavior, that

is the stress between almost constant with increase in strain

for that of 5%+15% cement+ glass powder content. Hence

increase in curing of samples 7, 14 days showed increase in

strength.

Curing

periods

( days)

UCC strength (kPa)

1.5%cement

+5% Glass

powder

3%cement

+10%

Glass

powder

5%cement

+ 15%

Glass

powder

0 23.5 43.2 68.7

2 62.8 89.3 128



591

7 67.7 147 167

14 118 206 235

Table 5 UCC strength of cured cement and glass powder

stabilized soil of (1.5+5%, 3+10% and 5+15%)


1.5%+5%, 3%+10%, 5%+15% cement+ glass powder

content cured for 2, 7, 14 days. Data presented in the table

bring out that the ucc strength of soil increased with increase

in fly ash content and as well, as increase in curing periods.

This due to the beneficial effects derived from soil- %

cement+ glass powder.

How ever , it can be observed that addition of 10% lime is

not much effective in improving the strength , when

compared to 3%+10%, 5%+15% cement+ glass powder

content.


cement,glass powder content

Table 2(e) summarizes strength ratio of stabilized soil with

with 1.5%+5%, 3%+10%, 5%+15% cement+ glass powder

content cured for 2, 7, 14 days . the strength of %, 5%+15%

cement+ glass powder is almost 3 to 5 times the strength of

%,1. 5%+5% cement+ glass powder treated soil for various

curing periods.

The soil treated with cement+ glass powder of 1.5%+5%,

3%+10%, 5%+15% the strength after 7 days is nearly 1.1 to

1.2 times as that of 2 days strength. Further after 14 days

curing the strength is increased to nearly 1.8 to 1.9 times the

2 days curing the strength for all fly ash contents

CONCLUSION

Soft clay deposits are geologically recent deposits which are

found in several parts of the world especially along the coast

in tidal plane and swamp areas. In tamilnadu also these

deposits occur in many parts like backwater areas of

kovalam

Based on the detailed experimental investigation and

analyzing the data the following conclusion are arrived

1.Soil exhibits very low strength when tested immediately

after mixing the stabilizers (lime, fly ash, cement & glass

powder with the soil. Hence curing period plays a major role

in improving the strength.

2.Unconfined compressive strength of soil treated with

various percentage of lime, fly ash, cement, glass powder

etc. showed increase in strength with increase in percentage

of stabilizers & increase in curing days.

3.In case of lime the overall increase in strength of 14th is 6

times to the strength 0th day lime.

4.In case of cement the overall increase in strength of 14th is

2.4 times to the strength 0th day cement.

5.In case of fly ash the overall increase in strength of 14th is

3.7 times to the strength 0th day fly ash.

6.In case of glass powder the overall increase in strength of

14th is 3.6 times to the strength 0th day glass powder.

7.In case of glass powder+ cement the overall increase in

strength of 14th is 10 times to the strength 0th day glass

powder+ cement.

8.The combination of soil + cement gives the predominant

value when compared to other stabilizers after the 2, 7, 14

curing periods.

REFERANCES

1.R. J. McLaren and A. M. Digioia, The typical engineering

properties of fly ash, Proc. Conf. on Geotechnical Practice

for Waste Disposal, ASCE, New York, pp. 683–697 (1987).

2. N. S. Pandian, Fly ash characterization with reference to

geotechnical applications(1998) IISC, Bangalore.

3. K. C. Sahu, S. Tripathy and C. Samuel, Geochemistry of

Indian coal and fly ash. Environmental considerations, Proc.

Int. Conf. on Environmental Impact of Coal Utilization from

Raw Materials to Waste Resources (K. C. Sahu, ed.), Indian

Institute of Technology, Bombay, pp. 23–38 (1991).

4. K. C. Sahu, Coal and fly ash problem, Proc. Int. Conf. on

Environmental Impact of Coal Utilization from Raw

Materials to Waste Resources (K. C. Sahu, ed.), Indian

Institute of Technology, Bombay, pp. 11–22 (1991).

5. J. P. Prashanth, Evaluation of the properties of fly ash for

its use in geotechnical applications, Ph. D. Thesis, Indian

Institute of Science, Bangalore (1998).



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Documents

UNCONFINED COMPRESSIVE STRENGTH OF STABILIZED SOIL · estimated by conducting unconfined compression test, Where astriaxial compression test, are used very rarely further the undrained