A STUDY ON SOIL STABILIZATION USING

LIME AND FLY ASH

Presented by,

Sreelakshmi Sajeev

Aswathy A.R

Meera .J.Krishnan

Aneena Elizabeth Jacob

Liyamol Isen

Resmitha Sasidharan

Jose Nibin Uthup

Kuwin Mathew

INTRODUCTION Roads are an importation means of

transportation Performance of pavements depend on

quality of materials used in road construction.

Subgrade is the base forming pavement

Quality of subgrade significant If local soils not able to withstand

loads,methods to enhance properties adopted

STABILIZATION AND MODIFICATION

Stabilization :blending and mixing materials with a soil to improve certain properties

Modification: reducing plasticity and improving the texture of a soil

.

SCOPE OF THE PROJECT Subgrade soil of Kumarakom is plastic clay Low bearing capacity Requires greater maintenance Proves to be costly Difficulty to travel in monsoon seasons Hence stabilization to improve properties of

the soil

OBJECTIVES OF THE PROJECT To explore the possibility of using fly ash in

road construction programme. To study the effect of lime and fly ash on

proctor’s density and OMC of clayey soil. To study the effect of lime and fly ash on the

consistency limits of clayey soil. To study the changes in CBR of soil by the

addition of lime and fly ash To study the effect of curing period on the

properties of native soil

USES OF STABILIZATION Quality improvement. better soil gradation, reduction of plasticity

index or swelling potential, and increase in durability and strength.

In wet weather, used to provide a working platform for construction operations.

Thickness reduction. As the strength and stiffness

improves,design thickness can be removed. 

STABILIZATION TECHNIQUES Stabilization with Portland cement Portland cement used to increase the

strength and durability. For stabilizing silt, sandy soils with small

quantities of silt or clayey fractions Stabilization with bitumen basic mechanism involved is water proofing

phenomenon. soil agglomerates coated with asphalt

prevents penetration of water improve durability characteristics

…CONTD

Stabilization with lime-cement and lime-bitumen 

one of the stabilizers in the combination compensates for the lack of effectiveness of the other

more costly than single stabilizer methods, but economical in areas where base aggregate costs are high.

Stabilization by geo-textiles and fabrics Geotextiles are permeable. Their

permeability is compared to that of fine sand to course sand and they are strong and durable.

STABILIZATION WITH LIME

done by adding lime to soil Reaction involves exchange of cations in the

adsorbed water layer decrease in the plasticity of the soil occurs lime-stabilized bases form a water resistant

barrier which stops penetration of rain water.

increase in optimum water content and a reduction in maximum density

..CONTD

liquid limit of soil decreases but the plastic limit increases.

plasticity index of the soil decreases strength of the lime stabilized soil

improved: due to the decrease in the plastic properties of the soil and formation of cementing material

Increase in the unconfined compressive strength is as high as 60 times.

modulus of elasticity of the soil increases substantially

MECHANISM OF STABILIZATION

Pozzolanic reactions induces stabilization Reaction of silica and alumina in clay and

calcium from lime Residual calcium keep the pH high enough

to maintain the pozzolanic reaction soils with a PI that exceeds 10 and have

more than 25 percent passing the #200 sieve

MECHANISM: POZZOLANIC REACTIONS

Silica(clay)

Alumina(clay)

Calcium(lime)

Cemented

structure

• Improves

strength

STABILIZATION WITH FLY ASH

Class C fly ash -byproduct generated at coal fired power plants

calcium compounds hydrate and produce cementitious products

rate of hydration for flyash is more rapid than Portland cement.

flyash has less effect on plasticity than lime.

PROPERTIES OF FLYASH

is non-plastic in nature. its moisture condition does not

predominantly affect the dry density. has high angle of internal friction. silt size material

LIST OF EXPERIMENTS

Atterberg limits Specific gravity Direct shear test Proctor compaction test CBR test Unconfined compression test(UCS)

MATERIALS USED

Clayey soil

:From kumarakom

Additives : fly ash lime

PROPERTIES OF NATIVE SOIL

Sl No: Properties Values

1 CBR value 4.3%

2 Max.dry density 1517 kg/m3

3 Optimum

moisture content

20%

4 Liquid limit 36%

5 Plastic limit 26%

6 Plasticity index 10

The lime percentage was fixed at 10% and flyash 14% based on UCS test

PROPERTIES OF FLY ASH

Physical properties

Specific gravity 2.27

Loss on ignition 11.8%

Chemical composition

Silica (SiO2) 58.3%

Alumina (Al2O3)+Iron oxide

(Fe2O3)

26.3%

Calcium oxide (CaO) 2.2%

LAB TESTING PROGRAMME Compaction test to determinethe quantity of water to be added for

field compaction of soil and resultant density expected.

Compaction of clay,clay-lime and clay-flyash mixtures were carried out using standard proctor test with three layers on each 25 blows.

Samples for conducting compaction tests were prepared using moulds of dimensions 10 cm diameter and 15 cm height. In this study, lime is added for about 10% and cured for 3, 7, and 14 days. Also,flyash is added for about 14% and is cured for 3,7 and 14 days. The values of optimum moisture content and maximum dry density are obtained in a plot of dry density versus moisture content.

0.4 0.6 0.8 1 1.2 1.4 1.60

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

3 days curing

7 days curing

14 days curing

normal stress (kg/cm2)

shea

r st

ress

(k

g/cm

2)

CBR

0 2 4 6 8 10 12 140

20

40

60

80

100

120

140

160

180

200

clay-fly ash mixture

3 days curing

7 days curing

14 days curing

native soil

penetration (mm)

load

(k

g)

UCC

400

1950

2250

18001950

native soil lime 5% lime 10% fly ash 12%flyash 14%