Prepared By: Patel Dharmik T (110780106024)

Patel Kush B (110780106035)

Patel Maulin R (110780106060)

Tank Harshida M (110780106047)

Guided By: Mr. Amar Y Salariya

Ms. Ankita S Patel

Content:

Why we choose this topic?

Introduction

What is Expansive Soil?

Group of Clay Minerals in Expansive Clays

Literature Review

Test performed.

Test Result

Conclusions

References

Why we choose this topic:

Expansive soils contain clay or other minerals that cause them to expand when

absorbing water. These soils often expand by 10 percent or more during a rainfall.

When the soils dry out, they shrink back to their original size.

Expansive soil expands due to the clay content.

When soils expand, they put pressure on structures. The soil exerts enough force

to crack foundations, floors and walls

If a structure is built while the soil is expanded, damage can occur when the soil

dries out and shrinks. This puts buildings at risk of collapse.

Expansive clay soils-those that change significantly in volume with changes in

water content-are the cause of destructions to structures that cost taxpayers several

billion dollars annually in the India. Much has been learned about their behavior

over the past 60 years, and relatively successful methods have been developed to

modify and stabilize them.

Introduction:

Expansive soils, also called swelling soils, are those in which volume change takes

place while it comes in contact with water i.e. expand during the raining season

due to intake of water and shrink during summer season.

The expansive soils in India have liquid limit values ranging from 50 to 100 %,

plasticity index ranging from 20 to 65 % and shrinkage limit from 9 to 14 %.

Expansive soils cover nearly 20% of the landmass in India and include almost the

entire Deccan plateau, Western Madhya Pradesh, parts of Gujarat, Andhra Pradesh,

Uttar Pradesh, Karnataka, and Maharashtra.

A major concern in geotechnical engineering is identification of expansive soils

and estimation of their swelling magnitudes when subjected to changes in

environment.

What is Expansive Soil ?

“Expansive soils are soils that expand when water is added, and shrink

when they dry out.”

Mixed layer minerals present in the soil can also cause swelling in expansive soils.

Montmorillonite–illite is most common mixed layer mineral present in expansive

soils.

Common combinations contain the expandable clay mineral montmorillonite,

interlayer with chlorite. The most important groups of clay minerals in expansive

clays are:

1-Montmorillonite

2-Illite

3-Kaolinite

Groups Of Clay Minerals In Expansive

Clays:

Classification of Expansive Soil Based On Liquid Limit, Standard

Penetration Resistance, Probable Expansion and Swelling Pressure:

Percentage Passing

No. 200 Sieve

Liquid Limit ( %)

Standard

Penetration

Resistance

(Blows/ft)

Probable

Expansion

(% Total

Volume

Change)

Swelling

Pressure

( Kg/cm2)

Degree of

Expansion

>95 >60 >30 >10 >10 Very high

60 – 95 40 -060 20 – 30 3 – 10 2.5 – 10 High

30 – 60 30 – 40 10 – 20 1 – 5 1.5 – 2.5 Medium

< 30 < 30 < 10 < 1 0.5 Low

Methods of Soil Stabilization:

There are two primary methods of soil stabilization used today:

• Mechanical

• Chemical or additive

Nearly every road construction project will utilize one or both of these stabilization

techniques. The most common form of “mechanical” soil stabilization is

compaction of the soil.

While the addition of cement, lime, bituminous, or other agents is referred to as a

“chemical” or “additive” method of soil stabilization.

About Rice Husk Ash:

Rice milling industry generates a lot of rice husk during milling of paddy which comes from the fields. During milling of paddy about 22% of the weight of paddy is received as husk This rice husk is mostly used as a fuel in the boilers for processing of paddy.

This husk contains about 75% organic volatile matter and the remaining 25% of the weight of this husk is converted into ash during the firing process, known as Rice Husk Ash (RHA).

This RHA in turn contains around 85% - 90% amorphous silica. So for every 1000 kg of paddy milled, about 220 kg (22%) of husk is produced, and when this husk is burnt in the boilers, about 55 kg (25%) of RHA is generated.

It is estimated that about 20 million tonnes of RHA is produced annually.

This RHA is a great environmental threat causing damage to the land and the surrounding area in which it is dumped, so it becomes necessary to find different methods of making commercial use of RHA.

Image of Rice Husk Ash:

Properties of Rice husk ash:

Description Abbreviation Percentage (%)

Silica Sio2 60.26

Iron Fe2o3 5.03

Calcium Cao 8.35

Magnesium Mgo 0.40

Sodium Na20 1.33

Potassium K2o 5.57

Chloride Cl 0.20

Sulphate So4 1.30

Phosphorus P2o5 2.69

Loss of Ignition - 3.39

Alumina Al2O3 10.73

Titanium Tio2s 0.13

Manganese Mn 0.078

Wax Content - Nil

RHA as Lightweight Fill:

The ash would appear to be a very suitable light weight fill and should not present

great difficulties in compaction, provided its initial moisture content is kept within

reasonable limits (say less than 50%).

The very high angle of internal friction of the material will mean that its stability

will be high.

However, the lack of cohesion may lead to problems in construction due to erosion

and shearing under heavy rollers.

To overcome these problems, it is desirable to place a 3 to 6 inch thick blanket

layer of cohesive material for every 2 to 3 ft.

Literature Review:

“Treatment of Expansive Clayey Soil with Crushed Limestone” :

-Al-Khashab

This paper aims at the improvement of expansive clays, by the addition of crushed

limestone, obtained from the waste of masonry factories situated in the polluted

industrial area, to the east side of Mosul city. This abandoned waste material

creates serious environmental problems in the areas surrounding these factories

requiring an urgent solution to dispose of the huge quantities heaped in there.

Different percentages of the crushed limestone by weight (passing sieve No.40)

were added namely (2, 4, 6, 8, and 10%) to the clay obtained from "Al- Wahda

district in Mosul" to reduce its expansiveness and improve its characteristics for

many earth work construction. The test results showed pronounced reduction in the

plasticity of the clay and significant decrease in the swelling properties, in the

range of more than three and half times that of untreated one. These results

represent very important factor for road embankment constructions.

Literature Review:

“Potentials of Rice Husk Ash for Soil Stabilization”

-Musa Alhassan

Soil sample collected from Maikunkele area of Minna, classified as an A-7-6

lateritic soil on AASHTO classification was stabilized with 2-12% rice husk ash

(RHA) by weight of the dry soil. Using British standard light (BSL) compaction

energy level, performance of the soil- RHA was investigated with respect to

compaction characteristics, California bearing ratio (CBR) and unconfined

compressive strength (UCS) tests.

The results obtained, indicates a general decrease in the maximum dry density

(MDD) and increase in optimum moisture content (OMC) with increase in RHA

content. There was also slight improvement in the CBR and UCS with increase in

the RHA content. The peak UCS values were recorded at between 6-8% RHA,

indicating a little potential of using 6-8% RHA for strength improvement of A-7-6

lateritic soil.

Literature Review:

“Soil Stabilization with Fly ash And Rice Husk Ash”

-Dr. Robert M. Brooks

The objective of this paper is to upgrade expansive soil as a construction material

using rice husk ash (RHA) and fly ash, which are waste materials. Remoulded

expansive clay was blended with RHA and fly ash and strength tests were

conducted. The potential of RHA-fly ash blend as a swell reduction layer between

the footing of a foundation and sub grade was studied. In order to examine the

importance of the study, a cost comparison was made for the preparation of the

sub-base of a highway project with and without the admixture stabilizations.

Stress strain behaviour of unconfined compressive strength showed that failure

stress and strains increased by 106% and 50% respectively when the fly ash

content was increased from 0 to 25%. When the RHA content was increased from 0

to 12%, Unconfined Compressive Stress increased by 97% while CBR improved

by 47%.

Tests Performed:

I. Sieve Analysis:

Objective: To determine the percentage of different grain sizes

contained within a soil.

II. Liquid Limit:

Objective: To Determine the moisture content, expressed

as a percentage of the weight of the oven-dried

soil, at the boundary between the liquid and plastic

states of consistency.

III. Plastic Limit:

Objective: To Determine the moisture content,

expressed as a percentage of the weight

of the oven-dried soil, at the boundary

between the plastic and semi solid

states of consistency.

IV. Specific Gravity:

Objective: To determine the specific gravity of soil

by using a pycnometer.

Continued:

V. Standard Compaction Test:

Objective: To determine the optimum moisture

content at which the maximum dry unit

weight is attained.

VI. CBR Test:

o Objective: Determination of CBR of soil either

in undisturbed or remoulded and

unsoaked condition.

Continued:

Result:

Property Quantity(Black cotton soil)

Specific gravity 2.2

Consistency limits

Liquid limit(%)

Plastic limit(%)

Plasticity index(%)

72

36.19

35.81

OMC(%) 19.8

MDD(gm/cc) 1.6

Unconfined compressive

strength(kg/cm2)

1.12

C.B.R. of specimen at 2.5mm

penetration

2.55

C.B.R. of specimen at 5mm

penetration

2.05

Atterberg’s Limits For Rice Husk

Ash: Soil-RHA

Mixture

Specific Gravity Liquid Limit Plastic Limit Plasticity Index

100% Soil + 0%

RHA

2.3 72 36.19 35.81

95% Soil + 5%

RHA

2.03 66.82 38.81 28.01

90% Soil + 10%

RHA

1.8 65.47 39.06 26.41

85% Soil + 15%

RHA

1.53 61.22 40.93 20.29

0

0.5

1

1.5

2

2.5

0% 5% 10% 15%

Specific Gravity

Specific Gravity

Variation of Specific

Gravity with different

RHA content.

54

56

58

60

62

64

66

68

70

72

74

0% 5% 10% 15%

Liquid Limit

Liquid Limit

Variation of Liquid

limit with

different RHA

cotent.

33

34

35

36

37

38

39

40

41

42

0% 5% 10% 15%

Plastic Limit

Plastic Limit

Variation of Plastic limit with different RHA content

Standard Proctor Test:

Variation of results in MDD and OMC of soil with

different RHA content

% RHA 0% 5% 10% 15%

OMC 19.8 18.9 16.8 15.3

MDD 1.6 1.75 1.83 1.98

0

5

10

15

20

25

0% 5% 10% 15%

OMC

OMC

0

0.5

1

1.5

2

2.5

0% 5% 10% 15%

MDD

MDD

Variation of results in OMC of

soil

with different RHA content.

Variation of results in MDD of

soil

with different RHA content.

Free Swell Index Test:

0

5

10

15

20

25

30

35

40

0 5% 10% 15%

Free Swell Index(%)

Free Swell Index(%)

Soil – RHA Mixture Free Swell Index(%)

100% Soil + 0% RHA 37.4

95% Soil + 5% RHA 31.3

90% Soil + 10% RHA 28.7

85% Soil + 15% RHA 22.6 Variation of FSI with different RHA content

Variation of result of CBR at 2.5 mm Penetration of soil

with different RHA content

%RHA 0% 5% 10% 15%

CBR at 2.5 mm

Penetration

1.27 1.49 2.31 2.27

CBR at 2.5mm Penetration:

0

0.5

1

1.5

2

2.5

0% 5% 10% 15%

CBR at 2.5 mm Penetration

CBR at 2.5 mmPenetration

Conclusion:

•Soil stabilization method by applying waste product rise husk ash was successfully

applied to improve the existing poor and expansive sub grade soil.

•Rise husk ash is free of cost and available locally, hence it proved economical also.

•Rise husk ash effectively dries wet soils and provides an initial rapid strength gain,

which is useful during construction in wet, unstable ground conditions.

•Rise husk also decreases swell potential of expansive soils by replacing some of the

volume previously held by expansive clay minerals and by cementing the soil

particles together.

Future Scope:

One can do same work for the different zone of Baroda city, as this material

is easily available.

One can go for further more depth as per requirement

Instead of Rice ash, we can use bio-enzymes or other suitable waste

material,which is locally available.

References:

1. Dakshanamurthy V. and Raman V, “Identification of expansive soils from

classification tests”

2. Dr. ROBERT M. BROOKS, Soil Stabilization With Flyash And Rice Husk Ash

3. Dif A.F. & Blumel W.F. (1991), “Expansive soils with cyclic drying and wetting”

ASTM, Geotechnical Testing Journal, pg. 96-102.

4. Emilio M.Morales and Mark K.Morales, “Expansive Soils–Identification,

Detection And Remediation Strategies”

5. Holtz W. G. and Gibbs H. J. (1956) Engineering properties of expansive

clays: Transactions, ASCE pg. 121, 641-677.

6. John, D.N. and J.M. Debora, 1992, “Expansive Soils-Problems and practice in

foundation and pavement engineering”, John Wiley & Sons. Inc., New York.

7. K.S.Berawala and C.H.Solanki By “Empirical Correlations Of Baroda Region

Expansive Soils Parameter Based On Swelling Characteristics”

References:

8. Mesfin Kassa, “Relationship between Consolidation and Swelling

Characteristics of Expansive Soils of Addis Ababa” Addis Ababa University

School Of Graduate Studies March 2005 pg. 1-4.

9. Nayak N.V. And Christensen R.W, “Clays and Clay Minerals, 1971 Vol. 19”

Pergamon Press. Printed in Great Britain. pg.251-261

10. Norrish K., “The Swelling of Montrnorillonite” Discussions The Faraday

Society. Vol. 18, 1954. pg.120-134.

11. Salma Tawfiq and Zalihe Nalbantoglu, “Swell-shrink behavior of expansive

clays” 28-30 May 2009 pg. 336-340.

12. S. Bhuvaneshwari, R.G.Robinson, S.R.Gandhi, Stabilization Of Expansive

Soils Using Flyash.

13. Srirama.A.Rao and Phani Kumar B.R.,“Correlation studies for swelling

characteristics of expansive soils”, pg. 59-63

14. Yusuf Erzin and Orhan Erol, “Correlations for Quick Prediction of Swell

Pressures” EJGE paper 2004-0476.

Books:

1. Dr. B.C. Punmia, Ashok Kr. Jain, “Soil Mechanics and Foundations” vol. 16.

2. John D. Nelson, Debora J. Miller, “Expansive Soils: Problems and Practice in

Foundation and Pavement Engineering” pg. 50-53.

3. Warren K. Wray, “So your home is built on expansive soils: a discussion of

how expansive affect buildings” pg. 25, 26.

Web-Site:

1. www.encyclopedia.com

2. www.whereisdoc.com

3. www.merriam-webster.com