Stabilization of black cotton soil using wooden ash..civil advanced project for future..

1. STABILIZATION OF BLACK COTTON
SOIL USING WOODEN ASH

2. Introduction
 Aimed at evaluating the possibility of utilizing
wooden ash in the stabilization of black cotton
soils
 Black cotton soils possess low strength and
undergo excessive volume changes, making their
use in constructions very difficult
 These soils cause more extensive damage than
even natural disasters
 Hence, we must increase the compressive
strength of black cotton soil with using of
wooden ash

3. Reasons for this Study
 Economic progress and growth of a country is closely
dependent on the infrastructural development
 Pavements of least thickness are found to be the most
economical
 This is possible only when the underlying soil has
greater strength
 Black cotton soil possesses low strength. If the soil is
weak, then the thickness of the pavements increases.
 So for such problematic soil, it is essential to stabilize
them in the most economic and affective way.

4. Feasibility of Wooden Ash
 Various research works have been undertaken for
improving the expansive nature of the black cotton
soil using materials like wooden ash, as admixture.
 Wooden ash is a locally available material residue
powder left after the combustion of wood, such as
burning wooden in a home fireplace or an industrial
power plant.
 It is used traditionally by gardeners as a good source
of potash for domestic gardens.

5. Material Source
Black cotton soil has been collected from a
field in Athupalam, Coimbatore
Wooden ash has been collected from
Malumichapetti region.

6. Laboratory tests
 The following are the various laboratory tests
conducted on the samples collected
Specific Gravity test
Dry Sieve Analysis
Relative Density Test
Liquid Limit Test
Plastic Limit Test
Standard proctor compaction Test

7. Natural Moisture Content
NATURAL MOISTURE CONTENT
 All moisture content determination was done by the oven
drying method
 For the determination of natural moisture content, samples
were collected in polythene bag and immediately taken to the
laboratory for the test.
 The water content is calculated from equation.

8. Where m1 = mass of container (g)

m2 = mass of container and wet soil
(g)

m3 = mass of container and dry soil
(g)
The natural moisture content was determined
to be 26.95 %

9. Specific Gravity
The density bottle method The specific gravity
of the soil sample was done by using density
bottle method.
The sieved sample was grouped into
approximately four equal parts.
Each part was placed into dried 50cm3 density
bottle of known mass (M1) to the nearest
0.01gsing

10. The mass of each bottle with sample inside
was measured (M2) to the nearest 0.01g.
 Each bottle was then filled with water and
mixed thoroughly removing all air bubbles.
The bottle was weighed to a mass (M3).

11. Finally each bottle was washed and dried.
Water was introduced and the mass of the
bottle with water full taken (M4).
The specific gravity is expressed as :
Gs = =2.941
The average of the values was taken for
various samples.

12. Pychnometer

13. Particle Size Distribution
 The particle size distribution of the natural
soil was determined using the method specify
by BS 1377 (1990) for cohesive soil.
It specifies the use of both sedimentation
analysis and the dry sieving of the coarse
fraction

14. When the black cotton soil was treated with
2 - 12% wood ash by dry weight of soil at
optimum moisture content (OMC), less than
10% of the material passed through BS No.
 200 sieve, and therefore did not meet the
minimum requirement for sedimentation
analysis to be carried out.

15. Sieve Panals

16. Liquid Limit
 200g of the air dried BC soil passing 425–μm sieve size
was taken and was mixed with water and kneaded for
achieving uniformity.
 The mixing time was specified as 5 to 10 min. The soil
paste was placed in the liquid limit cup, and leveled off
with the help of the spatula.
 A clean and sharp groove was cut in the middle by
means of a grooving tool.
 The crank was rotated at about 2 revolutions per second
and the number of blows required to make the halves of
the soil pat separated by the groove meet for a length of
about 12 mm was counted.

17. Conclusion
• From this project we observed that when
admixture is added to black cotton soil
(wooden ash) there is a increase in strength of
soil and less change in volume of soil.
• Hence its can be used economical in
construction.

18. References
Study of Geotechnical properties of black
cotton soil www.bvmengineeering.ac.in
Electronic Journal of Geotechnical
Engineering- www.Ejge.com
Characteristics of wood ash and influence on
soil properties www.ncbi.nlm.nih.govpubmed
Wood ash – www.wikipedia.org