THIS PRESENTATION CONTAIN THE CONTENTS OF HOW TO STABILIZE THE BLACK COTTON SOIL.

1. METHOD OF SOIL
STABILIZATION

2.  Contents
 Definition
 introduction
 Method of Soil Stabilization
 Cement Stabilization
 Lime Stabilization
 Fly Ash Stabilization
 Bitumen Stabilization
 Conclusion
 References

3. Definition
Black cotton soil is one of major soil deposits of India.
They exhibit height rate of swelling and shrinkage when
exposed to changes in moisture content and hence
have been found to be most troublesome from
engineering consideration.
 Objectives:-
1) To improve the characteristics of soil at the site.
2) To increase in the stability of a underground opening such
as Tunnel.
3) To increase in the stability of slope or a vertical cut.

4. Introduction
In India about 51.8 million hectares of the land area are covered
with Expansive soils (black cotton soil). The Black cotton soils are
very hard when dry, but lose its strength completely when in wet
condition. Expansive soils are a worldwide problem that poses
several challenges for civil Engineers. The stabilization of the
problematic soils is very important for many of the geotechnical
engineering applications such as pavement structures, roadways,
building foundations, channel and reservoir linings, irrigation
systems, water lines, and sewer lines to avoid damage due to
settle of soft soil or to the swelling action of expansive soil.These
soil are predominant in states of Andhra Pradesh, Western
Madhya Pradesh, Gujarat, Maharashtra, Northern Karnataka,
Tamil Nadu and some parts of Southern Uttar Pradesh
(Bundelkhand area).

5. Methods of Soil Stabilization
Without Additives (Admixture)
With Additives (Admixture)

6. 1) Rearrangement of particles through compaction.
2) To increase the density of soil by addition or
removal of soil particles so that modification is
carried in gradation of soil.
3) Drainage of soil to reduce its water content and
accelerate the consolidation (Pumping, Electro –
osmosis, applying thermal gradient i.e. heating
or cooling)
Without Admixtures

7. 1) Known as Chemical Stabilization
2) Includes Cement, Lime, Fly Ash, Bitumen
Stabilization
With Admixtures

8. Cement Stabilization
 Cement stabilization is
done by mixing
pulverized soil and
Portland cement with
water and compacting
the mix to attain a strong
material.
 The material obtained
after mixing is known as
Soil Cement.

9. Factors affecting Cement Stabilization
 Type of soil
1) Granular soils with sufficient soil fines are ideally
suited
2) All inorganic soils
3) Soils with 20% of organic matter are generally
considered as unsuitable
4) Expansive soils (B.C. soil) are difficult to stabilized
with cement

10.  Quantity of Cement
1) A well graded soil requires about 5% cement,
whereas the poorly graded or uniform sand may
require 9% cement.
2) Non plastics silts requires about 10% cement and
plastic clay need about 13% of cement.
3) However the actual quantity of required cement for
a particular soil is ascertained by laboratory tests.
4) IS procedure is also available.

11.  Quality of water
1) The quantity of water used must be sufficient for
hydration of cement and for making the mix workable.
2) The field measurement of moisture is done as per IS
4332 part II.
 Mixing, Compaction and Curing
1) The mixing should be uniform and homogeneous.
2) Mixing should not be continued after the cement has
started hydrating.
3) Soil cement should be protected against against loss of
moisture by providing a thin bituminous coating.
Sometimes water proof papers, moist straw or dirt are
also used.

12.  Admixture
1) To increase the effectiveness of cement as
stabilizer, admixtures are sometimes added to
soil cement.
2) Admixture may reduced the amount of cement
required.

13. Lime Stabilization
 Lime stabilization is done by adding lime to the soil.
 It is useful for stabilization of clayey soil.
 When lime reacts with soil, there is exchange of cations in the
adsorbed water layer and decrease in plasticity of soil occurs.
 The material obtained is more suitable as subgrade.
 Quick lime and hydrated lime are used for lime stabilization.

14.  Applications:
 Mainly used for the compaction of sub-bases and
bases for improving the subgrades of roads.
 Lime is suitable for heavy plastic soils.
 Construction Procedure:
 The field construction of lime stabilized bases is
similar to that of soil cement.
 Since lime reactions are slow there is no strict
limitations of time.
 Lime can be added as powder or in the form of
slurry.
 After compaction curing is done for 7 days.

18. Fly Ash Stabilization
 Flyash stabilization can increase shear strength,
controls the shrink and swell behavior of soil and
improve the load carrying capacity.
 Decreases the permeability.
 Class C flyash is used for soil stabilization.
 Stabilizes soft soils with the help of soil and water.
 Equipment required:
 Distributor truck, grader, a pad foot roller, drum
roller and water truck.

19.  Construction Sequence:
 Prepare the site by establishing final grade on the
existing base course.
 Spread the flyash in predetermined
concentrations on the prepared surface.
 Mix (blend) the flyash and prepared surface by
adding water to the mixture.
 Compact the blended material with pad foot
roller in vibratory mode.
 Complete the final grading and roll with the drum
roller

23. Bitumen Stabilization
 Soil particles or soil agglomerates are coated with
asphalt that prevents or slows the penetration of water
which could normally result in a decrease in soil
strength.
 In addition, asphalt stabilization can improve
durability characteristics by making the soil resistant
to the detrimental effects of water such as volume.
 The asphalt coating on the cohesionless materials
provides a membrane which prevents or hinders the
penetration of water; thereby reducing the tendency
of the material to lose strength in the presence of
water.

24.  By Water Proofing inherent strength and other
properties could be retained.
 Most Commonly used materials are Cutback and
Emulsion.
 Bitumen Stabilized layer may be used as Sub-base
or base course for all the roads.

26. Conclusion
 As if the locally available soil has generally high
plasticity (LL > 50) it was difficult to use it directly for
construction so some material to be added to the
soil.
 From the results, it is concluded that, the soil
stabilization using lime, bitumen, cement and fly ash
is a very effective process for the strengthing of soil.
 During comparison the clay obtains maximum
strength.

27.  Due to stabilization the soil the bearing capacity
of the soil gets increasing and any foundation
can be construction in the soil.
 Since lime and fly ash are low cost material it
obtains high strength and makes the structure
strong and durable.
 The C.B.R. value of black cotton soil improves
considerably to 3.25 times and 4.76 times with 3%
and 5% adding of lime respectively.
 From the results it is concluded that the impact of
lime, bitumen, cement and fly ash on black cotton
soil is positive. By replacing soil by half of its dry
weight by lime, bitumen, cement and fly ash it
gives maximum improvement in the engineering
properties of black cotton soil. So use of lime,
bitumen, cement and fly ash is preferable for
stabilization because it gives positive results as
stabilizer.

28. References
 O. C. McDowell, “Stabilization with lime, lime-fly ash, and other lime
reactive materials”, High Ress Board, Vol 231, pp. 60-61, 1959.
 A. Kezdi, “Stabilized Earth Roads”. Amsterdam: Elsevier Scientific
Publishing Company, 1979. [3] T. S. Nagaraj, and N. Miura. “Soil Clay
Behaviour, Analysis and Assessment”, Brook Field, Rotterdam: AA.
Belkema, 2001.
 A Study on Some Geotechnical Properties of Lime Stabilized Expansive
Soil – Quarry Dust Mixes by Dr. Akshaya Kumar Sabat (SSN 2249-6149
Issue 2, Vol.1 (January -2012 Pg. No 42-49).
 R.K.Katti (1979) ―Search for Solutions to Problems in Black Cotton
Soils- IGC Annual Lecture, Indian Geotechnical Journal-Vol.9.
 Soil Mechanics And Foundation Engineering by Dr. K.Arora.
 Soil Mechanics and Foundation Engineering By B.C. Punmina.
 Anonymous: IRC: 37, Guidelines for the design of flexible pavements,
IRC, 2001.

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