Soil stabilization:
If the stability of local soil is inadequate for supporting Wheel
loads, soil stabilization to techniques are implied improve the quality of such
inferior soil, strength, density, bearing capacity etc. Stability of soil is
often achieved by:
-
Proportioning
techniques involving mixing of various types of soil together with aggregates
etc. and compacting,
-
Use of
cementing materials ie omc, lime, bitumen etc. with soil mixed, blended and
well compacted,
-
Use of
modifying agents like stabilizers etc.,
-
Use of
water proofing agents to stop ingress of water into weak soil
-
Use of
water repellent agents,
-
Heat
treatment,
-
chemical
Stabilization techniques
Technique of soil stabilization:
1) Mechanical Methods:
It involves mixing and blending of various types of construction
materials together like coarse aggregate, fine aggregate, soil etc. in required
proportions to obtain designed stability after compaction. It is affected by
the following factors.
-
Property
of soil,
-
Gradation
of aggregates,
-
Mechanical
strength of aggregates,
-
Compaction,
-
Presence
of salts, mica organic matters etc.
2) Soil-Cement Stabilization:
soil, cement and water are blended well and compacted to form a strong
sub-base and base course. The cement hereby acts as strengthening and bonding
agent. Such materials are however, weak in abrasion and thus can't be used in
surface works / wearing course. It is often effected by:
- Type of soil,
- Type and amount of cement,
- Mixing and pulverisation,
- Amount of compaction and curing,
- Addition of admixtures etc.
3) Soil- lime Stabilisation:
Clayey soils have high plasticity index for which lime is used as
modifier / binder which considerably reduces the P. I. of such soils making
them friable and easy to be pulverised with very less affinity with water.
Soil-time stabilisation is affected by:
- Type of soil,
- Type and amount of time content,
- Compaction and curing,
- Addition of additives.
4) Soil- bitumen Stabilisation:
This is done by the use of cutback and emulsions for waterproofing and
binding such that the inherent strength and other properties are retained. It's
affected by following factors:
- Type of soil,
- Type and amount of bitumen,
- Mixing and compaction,
- Curing,
- Additives.
5) Stabilisation of Black - Cotton Soils:
Due to high volumetric variations in black cotton soils and their high
plasticity nature, cement or lime are used. for cost effectiveness, line is
more frequently used. This process modifies the following properties:
- P.I. is decreased to as much as zero,
- Affinity with water and thus volumetric variations are decreased by
large extent,
-Less shrinkage after compaction,
- Less cement requirement.
- following measures are adopted for stabilising the black cotton
soils:
- Subgrade soil is treated with little lime upto desired depth,
- Well compacted soil-lime for sub-base course,
- Soil- lime with admixtures for base course &
- Preferably superior type of materials in surface course.
Soil stabilization
black cotton soil
subgrade soil
less cement
soil lime
admixture
mechanical methods of soil stabilization
soil bitumen method
emulsion
water profing
cutback
superior material
shrinakge
base cources
well compacted
shrinkage
PI
pulverization
additives
curing
binder
high plasticity
optimum density
gradation of aggregate
compaction
density
salts in soil
mica
organic matters
water
