Stabilization of black cotton soil presentation

1. STABILIZATION OF
BLACK COTTON
SOIL
Presented By:
Mujeeb Ul Rehman
PG Geotechnical Engineering (Ist semester)
2020CEM029
And a special thanks to Dr. Nisar Hussain Mubaraki
for guiding me throughout the journey.
1

2. 2
What is Soil Stabilization?
Bird’s view to Black Cotton Soil
Materials used for Stabilization of Black Cotton Soil
Experimental Studies of various researcher’s
Conclusion
References
CONTENTS

3. • Utilization of land has increased due to increase in population, industries etc.
which have increased the demand for the available land. In order to cater this,
constructors have started laying foundation on soft grounds and expansive
soils. Due to low bearing capacity, large settlements of said soils, researcher's
have to think on it as how to deal with such situation. To get out in such
problems many techniques were formulated in which soil stabilization is one
such technique.
• Soil Stabilization is the technique of improving the engineering properties of
soil by varying its properties in such a way that it can be used in various
engineering works and it behaves quit satisfactorily[1]
• In other words, Soil Stabilization is the method of enhancing the engineering
properties of soil by addition of external material[1]
What is soil stabilization?
3

4. Purpose of soil
stabilization
• To improve certain
undesirable properties of
soils such as excessive
swelling and shrinkage,
high plasticity, difficulty
in compacting etc.
• To facilitate the
compaction and
increase load bearing
capacity.
• To reduce Compressibility
and thereby settlements.
• To improve
permeability
characteristics.
• Economic
4

5. Methods of Soil Stabilization
• Compaction and drainage are considered the simple methods of stabilization
of soil.
• Broadly speaking there are mainly two methods of soil stabilization:
1. Mechanical Stabilization
2. Chemical Stabilization
5

6. Mechanical Stabilization
• This is a more traditional approach (however, it’s still used today, in some
cases) and refers to either compaction or the introduction of fibrous and other
non- biodegradable reinforcements to the soil. This practice does not require
chemical change of the soil.
• There are several methods used to achieve mechanical stabilization.
 Compaction
 Soil Reinforcement
 Addition of Graded Material
6

7. Chemical Stabilization
• Under this category, soil stabilization depends mainly on chemical reactions
between stabilizer (cementitious material) and soil minerals to achieve the
desired effect.
• The Chemical reaction between the added material and soil improves the
quality of soil.
• Some of the materials added are listed below
 Lime
 Fibers
 GGBS
 Fly Ash
 Bitumen
7

8. Black Cotton Soil
8
• Expansive soils are clay of high plasticity. They content essentially the clay
mineral montmorillonite.
• The soils have high shrinkage and swelling characteristics. The shearing
strength of the soils is extremely low. The soils are highly compressible and
have very low bearing capacity.
• The tendency of expansive soil to increase in volume due to infiltration of
water is resisted by the structure resting on the soil and as a consequence,
vertical swelling pressure is exerted on the structure.
• Swelling pressure develop if the soil is not allow to swell freely. The
magnitude of swelling pressure depends on the degree of expansion
permitted. If the swelling pressure exerted by soil is not controlled, it may
cause uplift and distress in structure
This slide is prepared from[3]

9. 9
Fig (a): Typical cracks in BC soil during dry season; Fig(b): typical crack scene on roads around Ambo,
and Fig(c): a serious damage on a house constructed on BC soil in Ambo, Ethiopia [2]

10. 10
Why to stabilize Black Cotton
Soil
• Expansive soils are clay of high plasticity. They content essentially the clay
mineral montmorillonite.
• The soils have high shrinkage and swelling characteristics. The shearing
strength of the soils is extremely low. The soils are highly compressible and
have very low bearing capacity.
• The tendency of expansive soil to increase in volume due to infiltration of
water is resisted by the structure resting on the soil and as a consequence,
vertical swelling pressure is exerted on the structure.
• Swelling pressure develop if the soil is not allow to swell freely. The
magnitude of swelling pressure depends on the degree of expansion
permitted. If the swelling pressure exerted by soil is not controlled, it may
cause uplift and distress in structure
This slide is prepared from[3]

11. 11
Serial
Number
Authors Material Used Experimental programme Reference Number
01 Harshita Bairagi,
R.K. Yadav, R. Jain
jute fibre of length 5 cm and
aspects ratio 15-20. % of fibre
used 0%, 1%, 2%, 3%, 4%
and 5%
Shrinkage Limit, OMC, MDD, CBR value,
Unconfined Compressive Strength.
[3]
02 Mahesh Vastrad, M.
Karthik, Varsha
Dhanavandi, M. S.
Shilpa
Lime (6%), GGBS (30%) &
Nano silica (0.3%, 0.6% &
0.9%).
Atterberg’s limit, Compaction test,
swelling index and California Bearing
Ratio (CBR)& Unconfined compressive
strength (UCS)test
[4]
03 P. Murthi, R.
Saravanan, K.
Poongodi
Silica Fumes (5%, 10%, 15%
and 20%)
Polypropylene (0.5%, 1.0%,
1.5%, and 2.0%)
Compaction test, UCS test [5]
04 Siddalingeshwara D
H, Mujeeb Ul
Rehman
Lime (8% & 10%), fly-ash (8%
& 10%) and GGBS (8% & 10%)
were separately added with the
Black Cotton Soil
Atterberg limits, compaction test,
UCT test
[1]

12. 12
Study I[3]
• Harshita Bairagi, R.K.Yadav, R.Jain studied the effect of jute fibre on the
engineering characteristics of Black Cotton Soil.
• In their study soil samples containing 0%, 1%, 2% to 5% of jute fibre were
prepared and the shrinkage limit, optimum moisture content, maximum dry
density, California bearing ratio and unconfined compressive strength were
conducted as per relevant IS code of practice.
• Conclusions from the experimental Work:
With the increase in the jute fibers percentage the shrinkage limit values
increases from 8.66% to 14.68%.(fig. d)
The Optimum moisture content values increase from 22.1 to 25.1 and the
Maximum dry density are also decreased from 1.61 to 1.56. (fig e & f)
There was a significant increase in California bearing ratio and unconfined
compressive strength values. The California bearing ratio increases from 1.8% to
4.1%and the unconfined compressive strength increases from 1.09kg/cm2 to
1.35kg/cm2. (fig g & h)
From the test results it can be concluded that the addition of jute fibers to
black cotton soil decreases its swelling behaviour and increase the C.B.R. and
unconfined compressive strength properties.

13. 13
Fig. d: Variation in shrinkage limit[3]
Fig. e: Variation in Optimum moisture content[3]
Fig. f: Variation of Maximum dry density[3]
Fig. g: Variation in C.B.R. values[3]
Fig. h: Variation in Unconfined
compressive strength[3]
CF0 - Clay with 0% jute fibers
Similarly for others

14. 14
Study II[4]
• Mahesh Vastrad, M. Karthik, Varsha Dhanavandi, M. S. Shilpa done the
stabilization of Black Cotton Soil by Using GGBS, Lime and Nano-Silica.
• In their experimental program, they added lime, GGBS and nano-silica in
different percentages with black cotton soil and tested the samples for
compaction, UCT, CBR and swelling index.
• Conclusion based on experimental work:
Waste management is one of the industrial wastes can be done economically
and efficiently.
The combination of soil with 30%GGBS & 0.6% nano silica gives more strength
to black cotton soil.
The combination of soil with 30%GGBS & 0.6% nano silica reduces Optimum
Moisture Content (OMC).
It is observed that with increase of GGBS, more stability of soil is achieved.
The combination of soil with 30%GGBS & 0.6% nano silica increase the
Maximum dry density of black cotton soil (MDD).

15. 15
 Stabilize the black cotton soil and increase the strength of soil and decrease the
swelling pressure and decrease the fluid limit and plastic limit.
 The combination of soil with 30%GGBS & 0.6% nano silica increases the
compressive strength value of black cotton soil.
 The combination of soil with 30% GGBS & 0.6% nano silica reduces Free
Swelling index of black cotton soil.
Fig. i: OMC & MDD values for soil,
30% GGBS & 6% lime[4]
Fig. j: CBR values with soil, 30%
GGBS, 6% lime & (0.3%, 0.6% &
0.9%) nano silica[4]
Fig. k: UCS values at soil, 6%
lime, 30% GGBS & nano silica
of (0.3%, 0.6%, 0.9%)[4]
Fig. l: Free swelling index
for at soil, 6% lime, 30%
GGBS and nano silica of
(0.3%, 0.6%, 0.9%)[4]

16. 16
Fig. m: Compaction curve
values for soil & soil, 30%
GGBS & 0.6% nano silica[4]
Fig. n: CBR values of soil and soil,
30% GGBS & 0.6% nano silica[4]
Fig. o: UCS values at soil & soil,
30% GGBS & 0.6% nano silica[4]
Fig. p: Free swelling index
values at soil & soil, 30%
GGBS & 0.6% nano silica[4]

17. 17
Study III[5]
• P. Murthi, R. Saravanan, K. Poongodi conducted the experiment on black cotton
soil stabilised with polypropylene and silica fume.
• They mixed black cotton soil with Silica Fumes (5%, 10%, 15% and 20%) and
Polypropylene (0.5%, 1.0%, 1.5%, and 2.0%) and tested for compaction, UCT,
and swell pressure.
• No doubt the chemical stabilisation improves the soil under compression but
have substantial problem in improving th tensile behaviour of soil. Fibres have
such ability to improve the tensile behaviour of soil
• Conclusion based on experimental Work:
The results indicated that the swelling potential characteristics were reduced
considerably with addition of 20% of silica fume and 1.5% of polypropylene. The
unconfined compressive strength (UCS) of soil was improved significantly with
the addition of 20% of silica fume and 1.5% of polypropylene fiber.

18. 18
Fig. q: Moisture – density relationship curve[5].
Fig. r (a) Effect of polypropylene fiber and silica fume on the dry density of
soil, (b) Effect of polypropylene fiber and silica fume on the optimum
moisture content[5]
Polypropylene (%) Polypropylene (%)
• The OMC and MDD show significant effect by adding silica fume and
polypropylene fiber mixture. However, the addition of polypropylene fiber shows
minimum effect in OMC and MDD decreased.
• The MDD decreased and the OMC increased with increase in silica fume. The
addition of higher percentage of silica fumes results decrease in MDD, which
filled the voids of the silica fume – polypropylene fiber clayey mixture (CSFPF)
sample. In the same way, the increase in OMC was due to surface area and
change in particle size distribution of CSFPF soil sample.

19. 19
• The shear strength test results specified that the addition of silica fume increases
the unconfined compression strength of soil. Although for all mixtures of ratios of
clayey soil sample increases the UCS value and the maximum value of UCS was
observed at 20% of silica with 1.5% of polypropylene fiber content.
Fig. s: Stress strain curve of UCS soil[5] Fig. t: Effect of the PF and SF on the UCS[5]

20. 20
• It was observed that the swelling pressure is reduced by adding the silica fume-
fiber mixture. From the experimental study, the swelling pressure effect was
reduced 45% by adding 20% of silica fume and 1.5% of polypropylene fiber. The
addition of silica fume – polypropylene fiber mixture with clay reduces the
plasticity characteristics of soil. The reinforced clay soil shows a stable in nature,
due to change in high plastic clay to low plastic clay characteristics
Fig. u: Combined swelling pressure curve with and without admixtures of BC soil[5]

21. 21
Study IV[1]
• Siddalingeshwara D H, Mujeeb Ul Rehman conducted a series of experiments on
black cotton soil blended with lime (8% and 10%), fly-ash (8% and 10%) and
GGBS (8% and 10%) and the samples were tested for Atterberg limits, Standard
Proctor test, Unconfined compressive strength.
• Conclusion based on experimental work:
Dry density shows an increasing trend with increase in lime, fly-ash, and GGBS
content. Moreover, optimum moisture content decreases with the increase in
stabilising agents used during the study.
Unconfined Compression Strength also increases with the increase in the
percentage of Stabilising agents used.
However, as the percentage of stabilizing agents increases the soil strength
parameters has kept on increasing because as the particle size decreases the
surface area increases due to which a proper bond gets established between the
soil particles ensuring proper stabilization.

22. 22
Fig v: Comparison of Proctor for BC Soil, BC+8% Lime, BC+10% Lime,
BC+8% Fly Ash, BC+10% Fly Ash, BC+8% GGBS, BC+10%GGBS[1]
Fig w: Comparison of Un-Confined Compression Test for BC Soil,
BC+8% Lime, BC+10% Lime, BC+8% Fly Ash, BC+10% Fly Ash,
BC+8% GGBS, BC+10% GGBS[1]

23. 23
Conclusion
Based on the studies I carried out I can put them short in few points:
 Different stabilisation techniques were formulated by different researcher's in
order to achieve the good strength, reduce the shrinkage and swelling to
minimum possible extent in black cotton soil.
 I personally cannot justify which is the best suited method for stabilisation of
black cotton soil as it depends on the site, project we are taking up, economy.
Moreover, in one or other way the results we obtain for different stabilising
agents were satisfactory.
 Researchers need to look on for some new materials which will not only help in
improving the properties of black cotton soil from macroscopic level but it should
improve it from atomic level. Moreover, these materials should be readily
available at least minimum cost

24. References
[1] Comparative Study on Stabilized Black Cotton Soil, Mujeeb Ul Rehman and D.H. Siddalingeshwara, 2020,
Vol. 05, Issue 06, 46-52.
[2] Strength and compressibility behaviors of expansive soil treated with coffee husk ash, M.K. Atahu,
F.Saathoff, A. Gebissa, 2019, Vol. 11, Issue 02, 337-348
[3] R.J. Harshita Bairagi, R.K. Yadav, Effect of Jute Fibres on Engineering Properties of Lime Treated Black
Cotton Soil, Int. J. Eng. Sci. Res. Technol. 3 (2014) 1550–1552.
[4] M. Vastrad, M. Karthik, V. Dhanavandi, M.S. Shilpa, Stabilization of Black Cotton Soil by Using GGBS,
Lime and Nano-Silica, Int. J. Res. Eng. Sci. Manag. 3 (2020) 1–7,
https://doi.org/10.47607/ijresm.2020.273.
[5] P. Murthi, R. Saravanan, K. Poongodi, Studies on the impact of polypropylene and silica fume blended
combination on the material behaviour of black cotton soil, Mater. Today Proc. (2020).
https://doi.org/10.1016/j.matpr.2020.09.004.
24

25. 25
THANK YOU