Effect of Fly-Ash on Geotechnical Characteristics of Black Cotton Soil

IJIRST –International Journal for Innovative Research in Science & Technology| Volume 2 | Issue 03 | August 2015 ISSN (online): 2349-6010

All rights reserved by www.ijirst.org 9

Effect of Fly-Ash on Geotechnical Characteristics

of Black Cotton Soil

Satyendra Singh Rajput R. K. Yadav

M.E. Scholar (Geotechnical Engineering) Associate Professor

Department of Civil Engineering Department of Civil Engineering

Jabalpur Engineering College Jabalpur, (M.P.) Jabalpur Engineering College Jabalpur, (M.P.)

Abstract

In this study, fly-ash is used as a stabilizing material to stabilize the expansive soil dealing with engineering characteristics as the

parameter for it. Present paper describes a study carried out to check the improvement in the properties of expansive soil with

fly-ash in varying percentages. Fly-ash is added in 10%, 20%, 30%, 40%, 50% and the change in index properties and

engineering characteristics is examined. It has been found that significant variation in liquid limit, plasticity index, and swelling

index. In expansive soil, liquid limit decreased from 55.2% to 36.3% and plasticity index decreased from 27.1% to 18.1% ,

differential free swell (DFS) also reduced from 52% to 14% respectively .the compaction test results showed increase in

optimum moisture content (OMC) from 19% to 23% and decrease in maximum dry density (MDD) from 1.63g/cc to 1.52g/cc.

Test result indicates that fly-ash has a potential to improve the properties of black cotton soil.

Keywords: Black Cotton Soil, Engineering Properties, Fly-Ash, Index Properties

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I. INTRODUCTION

Clay exhibit generally undesirable engineering properties. They expand when wetted and shrink when dried. The objective of

this paper is to upgrade black cotton soil as a construction material using fly-ash which is waste material. There are number of

soil improvement techniques they include stabilization by lime, cement, bitumen, chemicals etc. fly-ash is also used as

stabilizing material. Fly-ash is an industrial waste obtained from thermal power plant by burning of coal. . Disposal of waste

material produced from different industries, has a great problem. In India thermal power plants produce 130 MT per year.

Fly-ash as a waste product. Therefore bulk stabilization of fly-ash become very essential in view of huge production. The

objective of this research work is to utilize the fly-ash waste for the improvement of the characteristics of expansive soil like

black cotton soil. Specifically the paper present results of a laboratory investigation of the stabilization characteristics of black

cotton soil blended with fly-ash.

II. LITERATURE REVIEW

Many researchers have worked on use of industrial waste for soil stabilization. A study on strength characteristics of expansive

soil-fly ash mixes at various mouldings water content has been studied by satyanarayana at al. (2013). It has been reported that

fly-ash increases the strength and decreases the swelling characteristics and 20-30% fly-ash needed to stabilize expansive soil.

Bhuvaneshwari and Robinson (2005) studied the stabilization of expansive soil using fly-ash and they concluded that the

workability is maximum with 25% of fly-ash in soil. Mehta at al.(2013) studied stabilization of black cotton soil by fly-ash and

reported that the plasticity index decreases with increases the amount of fly-ash content. BROOKS (2009) studied “soil

stabilization with fly-ash and rice husk ash” and reported that the rice husk ash (RHA) content of 12% and a fly-ash content of

25% are recommended for strengthening the expansive sub grade soil while a fly-ash content of 15% is recommended for

blending into RHA to form a swell reduction layer.

Fly-ash is an industrial waste obtained from thermal power plants by burning of coal. The test result showed a significant

improvement in compaction and CBR characteristics. And fly-ash is found to be an effective waste material for the stabilization

of expansive soil.

III. METHODOLOGY

The black-cotton soil used in this study was mixed with fly-ash in different proportions and a series of laboratory tests were

conducted on samples containing various percentages of fly-ash i.e. 0%, 10%, 20%, 30%, 40% and 50% by dry weight of the

soil. The following tests were conducted on black cotton soil and fly-ash mixes as per relevant IS codes of practice:

Liquid limit.

Plastic limit

Plasticity index.

Effect of Fly-Ash on Geotechnical Characteristics of Black Cotton Soil (IJIRST/ Volume 2 / Issue 03/ 002)


Compaction characteristics.

Differential free swell (DFS) test.

California bearing ratio (CBR) test.

Fly-Ash A.

Fly-ash is used as stabilization material in this research. Fly-ash was obtained from, Beersinghpur thermal power plant , district

sehdol, Madhya Pradesh.

Black Cotton Soil B.

Black cotton soil used in this study was brought from Jabalpur engineering collage near NCC campus Jabalpur (M.P.). The

expansive soil is classified as Inorganic clay of high plasticity (CH) with expansive behavior.

A physical characteristic of clay sample is listed in table-1. Table – 1:

Index Properties of black cotton soil

S.No. Parameters Test Values

1. Soil classification CH (Inorganic clay of high plasticity)

2. Liquid limit % (LL) 55.2

3. Plastic limit %(PL) 28.1

4. Plasticity index%(PI) 27.1

5. Differential Free Swell%(DFS) 52

6. Optimum moisture content (OMC) 19.3%

7. Maximum dry density (MDD) 1.63g/cc

8. California bearing ratio (CBR) 1.8

Test Result: C.

Various tests were conducted on black cotton soil mixed with fly-ash in the different proportions as per IS code of the practice.

Test results are summarized in Table-2

Table – 2:

Test result of BCS with Fly-Ash (%)

S.No. Tests CF O CF 10 CF 20 CF 30 CF 40 CF 50

1. Liquid limit(LL)% 55.2 51.3 48.1 44.3 40.5 36.3

2. Plastic limit(PL)% 28.1 26.4 24.2 22.6 20.7 18.2

3. Plasticity index(PI)% 27.1 24.9 23.9 21.7 19.8 18.1

4. Differential free swell (DFS)% 52 41 32 25 18 14

5. Optimum moisture content (OMC) 19.3 21.1 23.0 24.1 23.5 22.1

6. Maximum dry density (MDD) 1.63 1.61 1.58 1.56 1.53 1.52

7. California bearing ratio (CBR) 1.8 2.5 5.1 4.6 2.2 2.0

Where:CF0=BCsoil+0%fly-ash,CF10=BCsoil+10%fly-ash,CF20=BCsoil+20%fly-ash,CF30=BCsoil+30%fly

ash,CF40=BCsoil+40%fly-ash,CF50=BCsoil+50%fly-ash.

FA= Fly-ash content

IV. RESULTS AND DISCUSSION

Test results variations of LL, PL, PI, DFS , OMC, MDD and CBR with the addition of fly-ash up to 50% by dry weight of soil

are shown in figure . The LL decreased from 55.2% to 36.3% as fly-ash content increased from 0% to 50% similarly, Plasticity

index decreased from 27.1% to18.1% and DFS decreased from 52% to 14% respectively. And optimum moisture content

increased from 19.3% to 24.1% and maximum dry density decreased from 1.63% to 1.52% and maximum CBR value obtained at

20% fly-ash. These test results indicates that the swelling behavior of the soil is considerably reduced .



Fig. 1: Variation of LL for BCS mixed with Fly-ash

Fig. 2: Variation of PL for BCS mixed with Fly-ash

Fig. 3: Variation of PI for BCS mixed with Fly-ash



Fig. 4: Variation of DFS for BCS mixed with Fly-ash

Fig. 5: Variation of OMC for BCS mixed with Fly-ash

Fig. 6: variation of MDD for BCS mixed with fly-ash



Fig. 7 : Variation Of Cbr For Bcs Mixed With Fly-Ash

V. CONCLUSION

Based on the laboratory tests conducted on black cotton soil mixed with the fly-ash from 0% to 50% by dry weight of the soil.

Following conclusions can be drawn:

Liquid limit of samples are decreasing with the increasing of fly-ash into the Black soil. It has been found that the liquid

limit decreased from the (55.2% to 36.3%).

Plasticity index decreased from 27.1% to 18.2%.

Differential free swell index has reduced from 52% to 14%.

Optimum moisture content increased from 19.3 % to 23 %.

Maximum dry density has reduced from 1.63% to 1.52%.

Maximum CBR value obtained at 20% fly-ash.

Above results indicates that the degree of expansiveness reduced to low. From this research it can be concluded that fly-ash

has a potential to modify the characteristics of expansive clay like black cotton soil and to make it suitable in many civil

applications.

REFERENCES

[1] Bhuvaneshwari S., Robinson R.G. and Gandhi S.R.(2005):”Stabilization of expansive soil using fly” Indian institute of technology madras, chennai-36 fly

ash utilization programmme (FAUP) , TIFAC, DST, new delhi-110016 ( fly ash India 2005, new Delhi ). [2] Brooks M. Robert ( 2009):“Soil Stabilization with fly ash and rice husk ash” international journal of research and reviews in applied science , volume 1,

Issue 3, PP-209-217.

[3] Chen, F.H. (1988),”Foundation on expansive soil”, chen & Associate, Elsevier publication,U.S.A. [4] IS 2720 : Part 16 : 1987 Method of Test for Soil – part 16 : Laboratory Determination of CBR.

[5] IS 2720 : Part XL : 1977 Method of Test for Soils – Part XL : Determination of Free Swell Index of Soils.

[6] IS: 2720 ( Part 2), 1973 , Method of Test for soils, Determination of water content. [7] Katti, R.K.(1979),”Search for solution to problem in black cotton soils”, First IGS annual lecture, Indian Geo-Technical journal , vol.9, pp-1-88.

[8] Phanikumar B.R.,& Radhey S.Sharma(2004) “Effect of fly ash on Engg. Properties of Expansive soil” Journal of Geotechnical and Geoenvironmental

Engineering vol.130, no 7, July, pp.764-767. [9] Reyes Arleen and Miguel pando(2007): “ Evalution of CFBC fly-ash for Improvement of Soft Clays” World of Coal Ash (WOCA), May 7-10, 2007,

Northem kentucky, USA. Vol.13, PP-1-13.

[10] Satyanarayana P.V.V, Kumar S.Hemanth , Praveen P, and Kumar B.V.Suresh(2013):”A study on strength characteristics of expansive soil-fly-ash mixes at various moulding water content” international journal of recent technology and engineering (IJRTE) ISSN: 2277-3878, volume-2 , Issue-5, PP-145-149.

[11] Sahu B.K.(2001),”Improvement in California Bearing Ratio of Various Soils in Botswana by Fly-ash” International ash Utilization Symposium, Center for

Applied Energy Research, University of Kentucky. [12] Zachary G. thomas (2002),”Engineering properties of soil-fly ash subgrade mixture”, Graduate Research Report, Lowa State university, Ames, Lowa.

Documents

Effect of Fly-Ash on Geotechnical Characteristics of Black Cotton Soil