This document presents the results of an experimental study on stabilizing black cotton soil using rice husk ash and fly ash. Standard Proctor compaction tests were conducted on black cotton soil mixed with various proportions of rice husk ash and fly ash. Maximum dry densities ranged from 1.37 to 1.68 g/cc depending on the mix. Unconfined compressive strength tests found strengths increased by up to 30% with 10% rice husk ash and 25% fly ash addition compared to untreated soil. The study concluded this mix was most effective for strengthening the expansive black cotton soil.

1. EXPERIMENTAL STUDY ON
STABILIZATION OF BLACK COTTON SOIL
USING RICE HUSK ASH AND FLY ASH

2. ABSTRACT
• Aim of our project is to determine the behaviour of black
cotton soil with rice husk ah and fly ash for stabilization
purpose.
• Normally black cotton soil having higher density. I will
determine the maximum dry density and unconfined
compressive strength and some other basic properties of
soil with this additives.
• Rice husk ash having higher bonding property and fly ash
having smaller specific gravity. So by using this additives
partly we will increase the strength of stabilization for
road construction. Extensive research is going on to find
the solutions to black cotton soils.

3. GENERAL
• Soil can be used as a load bearing material or construction
material. When used for these purpose soil posses
engineering properties to meet the experiments such as high
strength ,low settlement etc.
• The dual problem of swelling and shrinkage causes damage
to many lightly loaded structures.
• In order to proceed with construction under engineering
conditions, some techniques are needed to improve such
properties of the soil.

4. SOIL STABILIZATION
• Soil stabilization is referred to as procedure in which a
special proportioned /added or removed or other chemical
material is added to a natural soil material to improve one or
more of its properties.
• One of the common methods of stabilization can also be
achieved by mechanically mixing the natural soil and
stabilization agents and then the mixture is blended together
so as to obtain a homogenous mixtures.
• Commonly used stabilizing agents are
lime,cement,bitumen,polymers,calcium and sodium
chloride.

5. LITERATURE REVIEW
EFFECT OF STONE DUST ON THE STRENGTH
CHARACTERISTICS OF BLACK COTTON SOIL
STABILIZED WITH RICE HUSK ASH
Manjunath K R , Rohith L (2015)
• In the present study influence of stone dust on the quality
characteristics of Rice husk ash stabilized black cotton soil
to increase the features of sub grade soil were determined.
• Atterberg’s limit, Compaction, Unconfined Compressive
Strength (UCS) and California Bearing Ratio (CBR)
experiments were carried out on the specimens of native soil
and BC soil with stabilizers. Different specimens have been
made by taking soil with different percentage of stone dust
(5%, 10%, 15%, 20% and 25%).

6. CBR STUDIES ON EXPANSIVE SOIL USING
STABILIZED RICE HUSK ASH CUSHION
Dr. M. Rama Rao , K. Ramesh Babu , K. Siva Kiran(2015)
• These studies indicates that the soaked CBR increases with
increase in lime content up to 8%, beyond which it begins to
fall slightly. Thus, 8% may be considered as the optimum
lime content from the point of view of increase in soaked
CBR also.
• The soaked CBR of the expansive soil bed without any
cushion was as low as 0.85%. Provision of lime stabilized
rice husk ash cushion improves the soaked CBR to 21.02%.
Hence it can be used for sub-base.

7. BLACK COTTON SOIL
• Black cotton soil is the Indian name given to the expansive
soil deposit in the central part of the country.
• Black cotton Soil is a residual soil and contain the clay
mineral montmorillonite that causes excessive swelling and
shrinkage characteristics of the soil
• The swelling and shrinkage of the black cotton soil can lead
to damage the foundations of the buildings and road
pavements.

8. RICE HUSK ASH
• Water absorption will be more.
• Excellent mechanical properties like internal bond strength,
elasticity, abrasion resistance.
• Increase surface hardness.
• Light weight.

9. FLY ASH
• Fine residue collected from the burning of pulverized coal
in the thermal plant.
• Silty non cohesive material having a relatively smaller
specific gravity than normal soils.
• Grey in colour.

10. INDEX PROPERTIES OF SOIL
• Specific Gravity
• Grain size distribution
• Liquid limit
• Plastic limit
• Plasticity index
• IS classification
• HRB classification

11. 62
64
66
68
70
72
74
76
0 5 10 15 20 25 30 35 40 45
WATER
CONTENT
NO OF BLOWS
LIQUID LIMIT OF SOIL
WATER CONTENT
LIQUID LIMIT OF BC SOIL
From graph, water content corresponding to 25 blows
W˪=69%

12. • Flow index, IF = 73%
• Plastic limit, (WP)=29%
• Plastic index(Ip) = 40
• Toughness index,(IT)=0.55
• IS classification of soil=CH
• HRB classification=A-7-6

13. Differential free
swell(%)
Degree of
expansiveness
<20 Low
20-35 Moderate
35-50 High
>50 Very high
DIFFERENTIAL FREE SWLL INDEX
Differential free sell index= 80%
It is very expansive soil.

14. PROPERTIES OF BC SOIL
S.NO PROPERTIES VALUE
1 Specific Gravity (IS 2720: Part 3) 2.2
2 Grain Size Distribution(IS 2720:Part4)
a) Gravel
b) Sand
c) Fines
0.32
41.8
57.88
3 Liquid limit (%) (IS 2720: Part 5) 69
4 Plastic limit (%)(IS 2720: Part 5) 29
5 Plasticity Index (%)(IS 2720: Part 5) 40
6 Free Swell index (%) 80
7 IS classification of soil CH
8 HRB classification A-7-6

15. PHYSICAL PROPERTIES OF FLY ASH
Colour Grey
Specific Gravity 1.90 – 2.55
Plasticity Non plastic
OMC (%) at 38.0 – 18.0
MDD (g/cc) 0.9 – 1.6
Cohesion (kN/m² ) Negligible
Angle of internal friction 300 – 400
Compression index Cc 0.05 – 0.4
Permeability (cm/sec) 8 x 10-6 – 7 x 10-4
Coefficient of uniformity 3.1 – 10.7

16. PHYSICAL PROPERTIES OF RHA
Appearance Blackish grey powder
Odour Odourless
Specific Gravity 2.4
Bulk density (kg/m3) 96
Storage Avoid contact with
moisture

17. STANDARD PROCTOR COMPACTION TEST
FOR CLAY
From fig we observed that maximum dry density of
soil is 1.62 g/cc at the OMC of 14% .
1.5
1.52
1.54
1.56
1.58
1.6
1.62
1.64
0 2 4 6 8 10 12 14 16 18
DRY
DENSITY(g/cc)
WATER CONTENT %
soil+0% Replacement
clay

18. STANDARD PROCTOR COMPACTION TEST
FOR CLAY+10% RHA
From fig we observed that maximum dry density of soil is
1.40 g/cc at the OMC of 12%.
1.32
1.33
1.34
1.35
1.36
1.37
1.38
1.39
1.4
1.41
0 2 4 6 8 10 12 14 16 18
DRY
DENSITY(g/cc)
WATER CONTENT(%)
soil + 10% RHA
10%RHA

19. STANDARD PROCTOR COMPACTION TEST
FOR CLAY+10%RHA+5%FA
From fig we observed that maximum dry density of
soil is 1.37 g/cc at the OMC of 1.37%.
1.24
1.26
1.28
1.3
1.32
1.34
1.36
1.38
0 2 4 6 8 10 12 14 16 18
DRY
DENSITY(g/cc)
WATER CONTENT(%)
SOIL+10%RHA+5%FA
10%RHA+5%FA

20. STANDARD PROCTOR COMPACTION TEST
FOR CLAY+10%RHA+10%FA
From fig we observed that maximum dry density of
soil is 1.50 g/cc at the OMC of 12% .
1.3
1.32
1.34
1.36
1.38
1.4
1.42
1.44
1.46
1.48
1.5
1.52
0 2 4 6 8 10 12 14 16 18
dry
density(g/cc)
water content(%)
SOIL+10%RHA+10%FA
10%RHA+10%FA

21. STANDARD PROCTOR COMPACTION TEST
FOR CLAY+10%RHA+15%FA
From fig we observed that maximum dry density of
soil is 1.41 g/cc at the OMC of 12%.
1.26
1.28
1.3
1.32
1.34
1.36
1.38
1.4
1.42
0 2 4 6 8 10 12 14 16 18
DRY
DENSITY(g/cc)
WATER CONTENT(%)
SOIL+10%RHA+15%FA
10%RHA+15%FA

22. STANDARD PROCTOR COMPACTION TEST
FOR CLAY+10%RHA+20%FA
From fig we observed that maximum dry density of
soil is 1.42 g/cc at the OMC of 12%.
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
0 2 4 6 8 10 12 14 16 18
DRY
DENSITY(g/cc)
WATER CONTENT(%)
SOIL+10%RHA+20%FA
10%RHA+20%FA

23. STANDARD PROCTOR COMPACTION TEST
FOR CLAY+10%RHA+25%FA
From fig we observed that maximum dry density of
soil is 1.37 g/cc at the OMC of 14%.
1.22
1.24
1.26
1.28
1.3
1.32
1.34
1.36
1.38
0 2 4 6 8 10 12 14 16 18
DRY
DENSITY(g/cc)
WATER CONTENT(%)
SOIL+10%RHA+25%FA
10%RHA+25%FA

24. Compaction of clay + various proportions of RHA
and FA
From the fig it is observed that 10% RHA+20% FA has the
Maximum dry density compared to all other proportions.
1.2
1.3
1.4
1.5
1.6
1.7
1.8
0 2 4 6 8 10 12 14 16 18
DRY
DENSITY(g/cc)
WATER CONTENT(%)
clay + various proportions of RHA and FA
clay
clay +10%RHA
clay +10%RHA+5%FA
clay +10%RHA+10%FA
clay +10%RHA+15%FA
clay +10%RHA+20%FA
clay +10%RHA+25%FA

25. Compaction of clay + various proportions of
RHA and FA
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
RHA 10% 10% RHA+
5% FA
10% RHA+
10% FA
10% RHA+
15% FA
10% RHA+
20% FA
10% RHA+
25% FA
DRY
DENSITY
VARIOUS PROPORTIONS
BC SOIL
RHA AND FA

26. UCC of Clay+ various proportions of RHA and FA
From the fig ,clay with 10%RHA and 25%FA gives
maximum unconfined strength.
0
20
40
60
80
100
120
140
0 100 200 300 400 500 600 700
STRESS
KN/m²
STRAIN
Chart Title
Clay+10%RHA
Clay+10%RHA+5%FA
Clay+10%RHA+10%FA
Clay+10%RHA+15%FA
Clay+10%RHA+20%FA
Clay+10%RHA+25%FA

27. UCC of Clay+ various proportions of RHA and FA
0
20
40
60
80
100
120
140
RHA 10% 10%
RHA+ 5%
FA
10%
RHA+
10% FA
10%
RHA+
15% FA
10%
RHA+
20% FA
10%
RHA+
25% FA
Stress
BC SOIL
RHA AND FA

28. Test Clay Rice husk ash and Fly ash
Proportion 0% 10%RHA 10%RHA
and 5%FA
10%RHA
and 10%FA
10%RHA
and 15%FA
10%RHA
and 10%FA
10%RHA
and 25%FA
Maximumu
dry density
g/cc
1.61 1.41 1.37 1.50 1.41 1.68 1.37
Unconfined
comprssive
strength
KN/m²
85.4 60.9 44.7 87 96.9 102.9 116.3
TEST RESULTS AND DISCUSION
From the above table it is observed that the unconfined
compressive strength increased from 85.4 for clay to 116.3.
So the percentage increase is 30%.

29. CONCLUSION
• From the above study the following conclusions are made.
• Stress strain behavior of UCC showed that failure stress and
strain increased by 30% and respectively when RHA
replacement of 10% and FA of 25%.
• The replacement of RHA and FA up to 10%RHA and 20%
FA gives a maximum dry density.
• The replacement of recommended for 10%RHA and 20%
FA strengthening the expansive soil.
• RHA and FA are available huge amount of tones in our
country at go downs.
• RHA and FA are place a vital role both in economy and
environment.

30. REFERENCES
• Dr. M. Rama Rao , K. Ramesh Babu , K. Siva Kiran(2015),
“CBR STUDIES ON EXPANSIVE SOIL USING
STABILIZED RICE HUSK ASH CUSHION”.
• Anil Kumar Singhai , Sudhanshu Shekhar Singh,
“LABORATORY STUDY ON SOIL STABILIZATION
USING FLY ASH AND RICE HUSK ASH”.
• Manjunath K R , Rohith L, “EFFECT OF STONE DUST
ON THE STRENGTH CHARACTERISTICS OF
BLACK COTTON SOIL STABILIZED WITH RICE
HUSK ASH”.
• “STABILIZATION OF BLACK COTTON SOIL BY
FLY ASH” by Ashish Mehta , Kanak Parate and B. S.
Ruprai

31. PROCTOR COMPACTION TEST

33. UNCONFINED COMPRESSIVE
STRENGTH

34. THANKING YOU