utilization of industrial waste for soil stabilization

Proceedings of International Conference on Advances in Architecture and Civil Engineering (AARCV 2012), 21st – 23rd June 2012 371

Paper ID GET106, Vol. 1

ISBN 978-93-82338-01-7 | © 2012 Bonfring

Abstract--- It is well said that a community without roads

does not have a way out. The growth of the population has

created a need for better and economical vehicular operation

which requires good highway having proper geometric design,

pavement condition and maintenance. Cost effective roads are

very vital for economical growth in any country. When poor

quality soil is available at the construction site, the best option

is to modify the properties of the soil so that it meets the

pavement design requirements. Commonly used materials like

cement and lime are fast depleting and this has led to an

increase in the cost of construction. The process of

manufacturing cement and lime are directly or indirectly

responsible for environmental pollution. At the same time the

disposal of various industrial wastes is creating problem. For

the growth of industries power requirement also increases.

Millions of tons of industrial by products are generated each

year in India, and significant percentages of these

by‐ products have desirable properties that make them

suitable for stabilization of soil.

Keywords--- Industrial Waste, Soil Stabilization, Fly Ash,

Steel Slag, Foundry Sand, Pond Ash, Stone Dust

I. INTRODUCTION

A. General

OR the construction of rural roads generally granular

materials like aggregates, coarse sand, murum etc. are

used. Now a day‟s availability of these materials has reduced.

Also the cost of construction of road increases due to

transportation of various required materials from a longer

distance. To avoid these problems it is required to improve the

properties of sub grade soil and try to reduce the thickness of

the roads. The rural roads are passing through clayey soil

which is more harmful to sub grade. Therefore it is required to

improve the properties of clayey soil. This is possible by using

industrial waste products. In our country maximum power is

generated by thermal power plants, which generate lakhs of

tones of pond ash and fly ash. There are some other industrial

wastes like steel slag, foundry sand, etc.

B. Use of Industrial Wastes in Construction

The various industrial wastes which can be used in

construction of roads to improve properties of soil are

discussed one by one in the following paragraphs.

K.A. Patil, Faculty, Department of Civil Engineering, Government

College of Engineering, Aurangabad (M.S.), India.

B.M.Patil, PhD, Student, Department of Civil Engineering, Government


L.K. Kokate, P.G. Student, Department of Civil Engineering, Government


C. Fly Ash

After combustion of coal fine particles are collected at

chimney by mechanically or electrostatic process and are

called as fly ash. It is very difficult to dispose fly ash on the

earth surface. If it is mixed with soil it reduces its fertility. If it

mixed with water it gets polluted. After pollution both the soil

and water are harmful to any living organism. Therefore it is

very important to develop the methods and techniques to

dispose of the fly ash more safely. Different investigators have

carried out studies on utilization of fly in road construction

with lime. Generally fly ash is used in proportion of 20 to 30

% of soil for stabilization. The amount of fly ash used in soil

stabilization can be increased by addition of certain

admixtures. There are various clayey soil stabilizers available

in liquid form and in powder form. Some of the soil stabilizers

are RBI Grade 81, Terrasil, Terrazyme, Bio-Enzymes etc.

If these stabilizers are used with fly ash, the various

properties of clayey soil are changed such as liquid limit,

plastic limit, and plasticity index. It also helps to reduce the

swelling and shrinkage behavior of clayey soil. There is also

increase in the CBR value and unconfined compressive

strength of clayey soil. If the CBR value increases the crust

thickness of the road decreases, due to this the construction

cost of road decreases considerably. Also due to use of soil

stabilizers the construction time reduces and roads can be used

as early as possible. The maintenance cost of the road also

decreases by 20 to 30%.

If the clayey soil, fly ash and RBI grade 81 are mixed with

different proportion at optimum moisture content, the CBR

value and unconfined compressive strength increases. If the

use of fly ash in road construction increasers it will help to

solve various problems related to environment. It is also

possible to use in situ soil as a sub grade material. Fly ash also

improves the swelling and shrinkage properties of clayey soil.

D. Pond Ash

In case of thermal power plant after burning coal near

about 20 to 30% of ash is collected at bottom. This ash is

disposed of in the form of slurry. After evaporation of

moisture the remaining ash is called as pond ash. For the

disposal of pond ash huge amount of land is required. This

method of disposal also results in soil pollution which may

also pollute ground water. Due to which it is not possible to

use ground water nearby pond ash ponds. Most of the

properties of pond ash are similar to that of fly ash. The use of

pond ash is very much limited. If the only pond ash is used for

soil stabilization, its amount is near about 10 to 20%. But if it

combines with some soil stabilizers, its amount can be

increased. If the combination of clayey soil, RBI Grade 81 and

pond ash are tested for CBR value and unconfined

compressive test, it is observed that the values of CBR and

unconfined compressive test are increased considerably.

Utilization of Industrial Waste for Soil Stabilization K.A. Patil, B.M.Patil and L.K. Kokate

F



ISBN 978-93-82338-01-7 | © 2012 Bonfring

E. Foundry Sand

Foundry sand is the byproduct material generated by metal

casting processes at metal foundries. Foundry sand is high

quality silica sand used to make the molds for casting the

parts. The sand is reused until it is physically degraded, at

which point it is removed from the sand supply. Foundry slag

is composed of fluxing agents and impurities removed from

the molten metal prior to casting. In the unprocessed state, the

sand may contain chunks of sand and binder (typically

bentonite clay), so crushing and screening may be required

based on the final use of the material. Screened foundry sand

is generally considered non plastic or low plasticity sand

depending on the type and amount of binder. It typically has a

uniform gradation, and has friction angle and cohesive

strength similar to natural sands. The presence of the bentonite

clays may provide superior compaction which may be useful

in increasing the CBR value and unconfined compressive

strength of the soil.

F. Blast Furnace Slag

Blast furnace slag is generated during the melting process

in steel making operations. The slag is a fairly complex mass

that is relatively inert. The cementitious binding properties of

blast furnace slag make it beneficial as soil stabilizer for

pavements. Experiments have shown that the mixing lime and

granulated blast furnace slag with 7.5 percent gypsum can be

used for making mortars which can further be used for making

concrete mixes for use in road bases and composite

pavements. This provides a great potential for profitable use of

this waste material and produces alternate binder to cement.

Blast furnace slag is used for roadbed, base course, or sub base

material. When blast furnace slag is used as stabilizer of sub

base it has various advantages such as what has been water

quenched tends to have a lowered wear resistance and

soundness. The sections of roadway in which blast furnace

slag was used as a means of providing soft ground

stabilization provided a degree of stabilization equivalent to

that of the traditional method of using rock aggregate. Use of

blast furnace slag is economical than conventional materials

within 30 km area of steel plants.

When lime and blast furnace slag mix was used as the soil

stabilizer where, 10 to 25 % of soil was replaced with lime and

blast furnace slag mix. The CBR value was increased in the

rise of 50% to 90% and the unconfined compressive strength

increased in the range from 15 to 45 kg/cm2. Addition of 7.5

percent gypsum to lime and blast furnace slag soil stabilized

mixes showed improvement of 110 to 240 percent and the

unconfined compression strength increased by 30 to 47

percent.

II. EXPERIMENTAL INVESTIGATIONS

In the present study soil sample was collected from Harsul

which is 4 kilometers from Aurangabad, Maharashtra State.

The properties of soil tested were as shown in table

1.Similarly table 2 shows properties of pond ash collected

from thermal power plant, Parali.

Table 1: Properties of Soil

Sr. No. Property Soil

1 Specific Gravity 2.59

2

Particle Size Analysis

Gravel Content % (4.75 to 80.00 mm) 6.33

Sand Content % (0.075 to 4.75 mm) 19.82

Silt and clay content % (below 0.075 mm) 73.85

3

Atterberg's Limits :

Liquid Limit % 70.46

Plastic Limit % 30

Plasticity Index % 40.46

4 Classification of soil CH

5 Maximum Dry Density (gm/cm3) 1.508

optimum moisture content % 22.03

6 Unconfined compressive test (kPa) 150.24

7 California Bearing Ratio % (soaked) 2.56

Table 2: Properties of Pond Ash

Sr. No. Physical parameters Values

1 Color Light Gray

2 Gravel % (4.75 to 80.00 mm) 0

3 sand % (0.075 to 4.75 mm) 79

4 Silt & Clay % (below 0.075 mm) 21

5 Specific Gravity 2.37

6 Plasticity Index Non plastic

In the present investigation the soil sample and pond ash

was mixed in the proportion of 90:10 and 80:20 to get the total

modified soil mixes. By keeping pond ash constant equal to 10

% and RBI GRADE 81 was additionally mixed in the range of

0 to 6 %. Similarly by keeping pond ash constant equal to 20

% and RBI GRADE 81 was additionally mixed in the range of

0 to 6 %. These modified soil samples were tested for soaked

CBR test and soaked CBR values of different modified mixes

are as shown in table 3.

From table 3 it is observed that, the soaked CBR value of

original soil without modification was found to be 2.56 %.

When the soil was modified using 10% pond ash, then the

increase in soaked CBR value was found to be 32.81 % of the

CBR value of original soil mass without any modification. By

keeping pond ash constant equal to 10% of the modified soil

mass and by varying RBI GRADE 81 content 0%, 2%, 4%

and 6% respectively, the soaked CBR values were found to be

3.4%, 4.87%, 12.5% and 18.28% respectively. In comparison

with 90:10 proportion of soil and pond ash for additional 2%,

4%, 6% RBI GRADE 81 the percentage increase in soaked

CBR values are found to be 43.24%, 267.64% and 437.64%

respectively. In comparison with original soil soaked CBR

value the percentage increase for modified soil mixes with

10% pond ash and 2%, 4% and 6% RBI GRADE 81 are found

to be 90.23%, 388.28% and 614.06% respectively.

Similarly by keeping pond ash as 20% of total soil

modified mass and varying RBI GRADE 81 in proportion of

2%, 4% and 6% the soaked CBR values are found to be 4%,



ISBN 978-93-82338-01-7 | © 2012 Bonfring

6.5%, 18.58% and 22.45% respectively. When the soil was

modified by using 20% pond ash, then the increase in soaked

CBR value was found to be 56.25 % of the CBR value of

original soil mass without any modification. In comparison

with 80% soil and 20% pond ash for additional 2%, 4%, 6%

RBI GRADE 81 the percentage increase in soaked CBR

values are found to be 62.5%, 364.5% and 460% respectively.

In comparison with original soil soaked CBR value the

percentage increase for modified soil mixes with 20% pond

ash and 2%, 4% and 6% RBI GRADE 81 was found to be

153.91%, 625.78% and 775.00% respectively.

Table 3: Effect of Pond Ash and RBI GRADE 81 on CBR

value of Soil

Soil % Pond Ash

%

RBI

GRADE

81 %

Soaked

CBR value

%

% increase

in CBR

value

100 0 0 2.56 0.00

90 10 0 3.4 32.81

88 10 2 4.87 90.23

86 10 4 12.5 388.28

84 10 6 18.28 614.06

80 20 0 4 56.25

78 20 2 6.5 153.91

76 20 4 18.58 625.78

74 20 6 22.4 775.00

III. CONCLUSIONS

Based on the literature reviewed and experimental

investigations carried out different conclusions drawn are as

given below.

i. The industrial waste products such as fly ash and

pond ash materials can be used as a replacement for

natural materials in construction, which may provide

a quality product and also help in reducing costs.

ii. Pond ash a waste industrial product can be used for

stabilization of clayey soils.

iii. Clayey soil by addition of pond ash showed

considerable decrease in maximum dry density and

increase in optimum moisture content.

iv. CBR values increased with increase in percentage of

RBI GRADE 81.

v. Fly ash can be used as the ingredient in pavements.

Pond ash which is also an industrial waste product

can be used in construction as structural fill material.

vi. Most foundry sands can be used as fine or coarse

aggregates in construction and soil applications.

These can also be useful for various solid matters

applications such as structural filling, granular base

and sub base.

vii. The beneficial use of industrial waste as landfill can

be used in a beneficial manner.

viii. When soil, pond ash and RBI Grade 81 are mixed in

a proportion 74:20:6 the CBR values of soil found to

be increased up to 775 percent of the original soil

mass.

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utilization of industrial waste for soil stabilization

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