a study on soil stabilization using lime and fly ash
DESCRIPTION
This paper is based on a study conducted on the plastic clay type soil of KUMARAKAM.TRANSCRIPT
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%