demolition waste thesis

CHAPTER -1
INTRODUCTION
1.1 General
Soil comprises of various elements,compounds,gases,liquids and endless bacteria,organisms that
are dependent on soil.It is important part of life cycle as food , housing ,agriculture,water storage
are hugely impacted by it.Soil is refered as “Earth’s skin”which is a essential link between
atmosphere and biosphere. Soil continously is in development mode from one phase to another
by means of various chemical,biological and physical processes.
Soil behaviour is of great importance and it is the reason human race exist on planet earth.Soil
mixed with various other materials was used as a great construction material in ancient and used
in modern age as well. Clay exhibit generally undesirable engineering properties. It tend to have
low shear strengths and to lose shear strength further upon wetting or other physical disturbances.
It can be plastic and compressible and they expand when wetted and shrink when dried. Some
types expand and shrink greatly upon wetting and drying. Cohesive soils can creep over time
under constant load, especially when the shear stress is approaching its shear strength, making
them prone to sliding. Clay develop large lateral pressures and tend to have low resilient modulus
values. For these reasons, clay is generally poor materials for foundations.
For many years admixtures such as lime, cement and are used to improve the qualities of readily
available local soils. Laboratory and field experiments have confirmed that the addition of these
admixtures can increase the strength and stability of such soils. However, the cost of introducing
these admixtures has also increased in recent years. This has opened the door for researchers to
find alternate admixtures such as Molasses,plastic, fibers, liquid enzymes, micro bacteria etc.

Soil is the cheapest construction material available and its been used since ages.Our ancestors had
realized effectiveness of soil as a binding and construction material.Soil properties can ve altered
by addition of various admixtures and waste available naturally or man made.India has large
diversity in weather,climate, region, topography due to which there is diversity in types of soil
available which makes it important to study the behaviour of soil. A large part of Central India is
covered with black Cotton Soils. Black soil covers approximately 30% of total soil mass area in
India.

Black Cotton Soil: Black soil is formed from Basalt or Trap rocks by physical and chemical
decmposition of heavy rocks.When Surface of large mass of rocks are exposed to atmosphere
for a period of time various chemical and physical processes lead to formation of soil.Black soil
is best suited for growing cotton crops that is why it is commonly know as “Black Cotton
Soil”.This type of soil is particularly clay of high plasticity having very low shearing strength
and low bearing capacity. Such soils swell in significance when soil comes in contact with
moisture and shrink in absence of it. Such soil of expansive nature in India is mainly the BLACK
COTTON SOIL. The expansive nature of such soils is due to the reason that Montmorillonite
mineral is present .
Montmorillonite has basic structural unit consisting of an alumina sheet sandwithced between
two silica sheets.Sucessive Structural Units are stacked over one another like leaves of a
book.The thickness of each structural unit is about 10A. The decomposition of silicate minerals in
the rock leads to formation of clayminerals such as kaolinite, illite and montmorillonite.These
clay minerals are hydrated aluminum silicates and hydrous oxides of aluminum, magnesium and
iron in a crystalline form of relatively complicated structure.

Molasses:Molasses is thick syrupy brown liquid which is produced as a waste during
processing of sugar cane in sugar mills.It contains high amount of Sucrose upto 40% which is
chemically C12H22O11.Sucrose contains Hydroxyl Group(OH+ ) which bonds with negitively
charged clay particles.Its melting point is 186 ºC.Molasses is acidic in nature due to which it is
considered a pollutant for land.Molasses has binding properties which makes it suitable to be
used as stabilzing agent for geotechnical works. Utilising molasses for stabilising expansive clay
shows promising results and it can solve problem of environment as well. The purpose of
molasses in this case was to minimize the moisture loss during the construction of pavement
layers. That means molasses in this case acted as a moisture content sustainer for
soilaggregate.The sustenance of moisture content was caused by hygroscopic properties of
molasses.

1.2 Need to Stabilize the soil
Soil behavior is function of its morphology and minerals present in it. Every year India faces
huge lose in terms of failure of structures like roads, buildings, embankments constructed on
expansive soils. Construction activities on Black cotton soil has always been a challenge for
Geotechnical engineers therefore, lots of effort has been put in to stabilize such soil with various
admixtures and waste materials. To evaluate the performance of soil at micro level studies like
XRD and SEM are much needed to identify the changes in soil structure due to stabilization.
Micro level study offers better understanding of the soil behavior at nano scale level.

 Soil is highly unpredictable and heterogeneous material unlike steel and concrete.
 Soil properties not only varies from place to place but also varies with depth of
excavation.It also depends upon environmental ,drainage and loading conditions.



Soil properties depend on various engineering parameters and it is difficult to predict soil
behaviour two or three parameters alone.Intensive testing is needed to determine soil
properties.

 As huge quantity of soil is involved it is not feasible to transport soil or replace soil.So it
is recommended to stabilise soil in the form it exists on site.

 Soil failure may result in heavy loss of life and property as black soil has low bearing
capacity, high compressiblity and high plasticity index which makes it unsuitable for
engineering works.


Use of binding materials like industrial waste,lime,molasses etc to stabilise weak mass of
soil into good construction material is very cost effective which shortens construction
period.



With decreasing resources and land area it is important to re-use waste material in
geotechnial engineering works.Using waste material will have great benefits for
environment as well.

1.3 Significance of Study


More than 30% of central india is covered with Black cotton soil which is expansive in
nature due to presence of montmorillonite mineral which posses great threat to life &
property as it expands with absorption of water and applies swelling pressure which can
be as high as 400 to 500 kn/m2.So there is urgent need to find out ways which are less
time consuming, cheaper and effective to stabilize the soil.



In the present study molasses has been used as an adhesive for Black soil because the
study should be such that it utilises industrial or any other waste so that there is no need to
worry about disposing off the waste.Molasses is also a industrial waste from sugar
indsutry ,it causes land degradtion by decreasing the Ph value of land,soil and makes it
unfit for vegetation by making land acidic in nature. Utilising molasses for stabilising
expansive clay shows promising results and it can solve problem of environment pollution
as well.

1.4 Research Objectives of the Study
The principle objective of this research work is: 1. The purpose of this research is to see the effectiveness of molasses in enhancing strength
and reduce swelling pressure of expansive soil.
2. To study the effect on unconfined Compressive Strength of Black Cotton Soil mixed with
molasses (in different proportion).
3. To observe the Load-Settlement behavior Black cotton soil and Soil mixed with molasses
using a Finite Element Method Software (Optum-G2).
4. To Study change in morphology of expansive clays due to addition of molasses using
Scanning Electron Microscopy
5. To find the optimum %age of molasses for maximising strength and minimising swell
pressure.

1.5 METHODOLOGY
In the present study, following steps are to be followed to achieve the identified objective: The
quantity of the molasses added will be (2%,4%, 6%, 8%, and 10%) by weight of the soil.

1. Determine the Atterberg limits of virgin soil and BC soil mixed with molasses in different
%(2,4,6,8,10).
2. Determine the Optimum moisture content and Maximum dry density of soil by standard
proctor test of each set of soil molasses mix.
3. Determine the Unconfined Compressive Strength Parameters by UCS test of virgin and
soil mixed with molasses.
4. Determine the Swelling pressure of soil and soil mix by swelling pressure test.
5.

Determine values of engineering parameters E,c, Ø by carrying out Triaxial test on
Black Cotton soil and optimum molasses mix.

6. Develop a numerical modelling of footing retained on Black cotton Soil and optimum soil
molasses mix .
7. To find the load carrying capacity of fotting and settlement of Black Cotton soil and
optimum mix.
Table 1 (a): Mix Proportions

CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
This chapter introduces the significant literature related to improvement of Black Cotton Soil
using a natural polymer (Molasses).Molasses stabilization is comparatively a new concept with
very limited work available on the topic, which opens new doorways of possibilities for
researchers. Molasses availability is also in abundance as India is amongst few largest producers
of sugar in the world. As previous work has shown molasses as a stabilizing agent can be very
effective.
Molasses is a great adhesive having net positive charge due to presence of (OH) hydroxyl group
in its structure.Net positive charge is capable of attracting negative charged clay particles to form
a better intermolecular bond thereby increasing strength and stability of expansive clays.
As molasses forms a coating around the soil grains which increase the soil grain size to reduce
the clay size particles and makes easy sharing of ions between the double diffused layers, which
makes a more flocculated soil structure.
On the other hand if molasses is added more than a specified limit coating formed is so thickened
that it pushes the soil grains apart, which decreases electro static attraction between the soil
particles that the effect of molasses starts reducing forming a less stable and soil with low
strength.

2.2 Literature survey
Koranne, S.S. and Shirsavkar, S.S. (2010) studied the viability of molasses to improve the
strength of weak soil and reduce dust-using molasses. He conducted CBR test on various
proportions of molasses mixed with soft Murum. Molasses % ages used for modification were
5%, 5.5% 6.0%, 6.5%, 7.0% and 7.5%. CBR value was maximum for 6.5% molasses mix with
soft murum. At 6.5%, ratio density increased to maximum thereby increasing the strength of soil.
In addition, plasticity index reduced for this ratio of molasses. He also studied the cost
optimization of sub grade using molasses. He observed molasses mixed in optimum quantity
saves cost from 15% to 40% as compared to conventional design for road.

M’Ndegwa, Julius. K. examined the mechanism of stabilization of expansive soil with cane
molasses. He observed that with addition of molasses the swelling pressure of Black cotton soil
reduced considerably. He conducted CBR test on soil molasses mix with varying %age of
molasses from (2 to 14)%. He examined reduction in swelling pressure is due to increased silt
and sand content and less clay content. This is due to the flocculated soil particles due to the
cation exchange process between the cations of molasses and easily exchangeable cation on soil
surface. Molasses has tendency to enhance flocculation and stability of soil aggregate as it has
adhesive properties due to presence of hydroxyl group (OH) which is mainly responsible for
properties of sugar and molasses. Hydrogen bonds are intermolecular in nature and have net
positive charge on them, which makes the molasses adhesive in nature and binds the soil particles
together thereby increasing the stability of expansive clay as clay particles are negatively
charged. Also the Expansive soil mixed with molasses provided higher CBR values with huge
reduction in swelling tendency of Expansive clay specimen. 6.5 % age of molasses by weight of
soil provided highest CBR value in the range of (0-8) % molasses with less swelling tendencies.

Above 8% percent, CBR values tend to fall due to thickened clay particles. With increased
coating of molasses on soil grains gap between the soil grains starts widening again because of
which intermolecular bond becomes weak.

Adel, D.et al., have used the analytical studies and software (Plaxis) to show that deformations
were mainly in the area direct in contact with the pavement under traffic. From odometer test
swelling pressure found was 350kn/m2 .the research does analytical study of pavement on
expansive soil along with suggest possible preventive measures to have minimum effect of it on
pavement. Surface cracks on pavement are visible due to shrinkage of expansive clay .the result
compiled from the simulation were checked on various soil models like Mohr coulomb on
pavement, soft soil in sub grade. Combination of both model depicts major displacements are in
shoulder of sub grade course with consolidation value 44.26x10-3m.subgrade acted like hard
elastoplastic soil while pavement acted non-linear elastoplastic soil. The suggested stabilization
technique for cyclic motion of expansive sub-grade is application of surcharge fill equivalent to
swell pressure.

Bose, Bidula observed that on addition of fly-ash plasticity Swelling character of expansive clay
are reduced as well as reduction in plasticity index and linear shrinkage was noticed. He
conducted swelling test, SEM test and found Fly ash has potential to stabilize expansive clay like
Bentonite because it has low unit weight, low specific gravity, easily compactable, good
coefficient of friction makes it highly desirable stabilizing agent. Fly ash decreased OMC with
increasing content of it where as max dry unit density was observed at 20% fly-ash mix in soil.
The result of unconfined compressive test is maximum at same content of fly ash where dry
density was maximum.UCS value shows increase at 20% fly-ash mix up to 40%.

Ravi, E.et al., Aim of the study was to carry the experimental investigation to study the
effectiveness of liquid stabilizing agent molasses in improving shear strength and CBR of highly
compressible clay. Basic experimental tests conducted were Atterberg limit test, Proctor test, free
swell, Specific Gravity test. Plasticity index came out to be 28%, free swell value was 32% and
specific gravity value was 2.8 for Virgin Black cotton soil. Proctor Test showed decline of MDD
with increasing % of molasses (0 to 12%) and same trend was seen for OMC as well. Molasses
quantity needed in maximizing the strength parameter was 6.5%.At optimum % value of UCS
increased up to 60% which was 91.6kn/m2 for virgin soil sample. Molasses enhanced cohesion
value of soil, which resulted in increased UCS and resisted CBR penetration.

Agarwal, Puneet.et.al., observed UCS trend of Expansive clay when treated with Bioenzymes
like Terrazyme, which is a natural, non-toxic liquid produced by vegetable extracts. These
additives reduce voids in soil particles and maximize compaction. They also have tendency to
control swelling behavior of expansive clays. The UCS test conducted on various dosages of
Terrazyme (0ml, 0.25ml, 0.5ml, 1ml, 2ml, 3ml) for 5kg sample of Black cotton soil showed
180% increase in UCS value for 1 day curing and 200% increase for 7 day curing. The optimum
percentage of Terrazyme came out to be 1ml/5kg of soil. He concluded that Terrazyme can be
used for any type of soil and its application is easy which assures safety for environment as well.
Duration of curing plays huge role in maximizing strength values of UCS , it can be as high as
200% of virgin black soil UCS value.

Bhavsar, Sachin.et.al. studied viability of marble powder and brick powder in controlling
swelling and shrinkage of black soil. The % of marble & brick powder selected was 40 and tests
performed were Atterberg limit test, linear shrinkage test and swelling test. Plasticity index of
black soil reduced from 26.1 to 19.93 on 40% addition of marble powder and for brick powder, it

reduced to 19.72.Linear shrinkage was 23.7% for black soil initially which dropped to 5& 7.8 for
marble and brick powder. Results of Differential free swell showed that marble powder is perfect
in stabilizing black soil as free swell was 0% in case of marble powder which was 50.50% for
virgin black soil sample. Marble powder gave better results as it is fine, less plastic and grated
well.

Parate, kanak.et.al. observed the effectiveness of fly ash through lab tests like CBR,Proctor test,
Atterberg test, specific gravity test in stabilizing black cotton soil. He conducted lab results to
estimate thickness of sub-grade of pavement to be built on black soil. Since it is not possible to
replace locally available soil it is better to stabilize on site. Flexible pavement faces huge
deformation due to loads, swelling pressure, which finally fails the sub grade or pavement. The
ratios of fly ash used varied from 10 to 50%. MDD is highest at 20% fly ash mix with soil. CBR
test values confirm the 20% fly ash gives higher value of CBR, which is as high as 22.90% then
virgin black soil.
Mahiyar, H.K.et.al. conducted experimental study on Black cotton soil + fly ash ,coconut coir
fiber mix and carried out study on swelling behavior ,CBR value of Black cotton soil mixed with
coconut fiber ,Fly ash . The study evaluates the effect of coconut fiber + soil mix for some
engineering properties of Black soil like plasticity index, compaction characteristics and CBR
value of Black cotton soil. Different proportions used for the experimental prog. varied from 10
to 25 % for fly ash and 0.25 to 1% for coconut fiber. The optimum percentage is 20%fly ash +1
% coconut fiber + Black cotton soil which showed CBR value of 5.2 and swelling pressure
reduced to 1/10th of value of virgin Black soil. Black cotton soil experimental results showed
swelling pressure of 3.5kg/cm2

for virgin sample and free swell value was 30%.He concluded

the coconut fiber used with fly ash in Black cotton soil increased CBR value from 1.5 to 5.2 and
reduced swelling tendencies of Black cotton soil up to 90%.

Annadurai, R.et.al. Studied particle size distribution of soil sample F1 contained 70% clay, 28%
silt and 2% sand and soil sample F2 contained 66% clay, 32 % silt and 2% sand. The specific
gravity of the soil sample F1 and F2 were 2.23 and 2.37 respectively. Tests for Geotechnical
properties of both the soils F1 and F2 were conducted as per the BIS and the test results are
shown in the Table 1. From the results obtained, it was identified that both the samples were
highly compressible clays.Phospho Gypsum (PG) is a by-product in the wet process for
manufacture of ammonium phosphate fertilizer by the action of sulphuric acid on the rock
phosphate. The phosphogypsum used in this study had SiO2 - 3.9%, CaO - 32.27 %, and Loss on
ignition of 16.5%.Fly Ash (FA) used in this study was collected from Neyveli, Tamil Nadu. It is
classified as Class F type as per the ASTM Standard C618, and it contained SiO2 - 35.2%,
Fe2O3 - 6.83%, Al2O- 27.4% and CaO - 19.2%. To find the effect of stabilization on soil
samples, PG varied from 2 to 6 percent with 5 percent FA by dry weight of soil was thoroughly
mixed with pulverized clayey soil samples and then mixed with distilled water for preparing
specimens to conduct the CBR tests. The effect of admixtures on CBR of soil mixes were
studied, after keeping the prepared samples for 3 and 7 days curing time before testing. After
testing, the specimens were air dried and pulverized, then free swell index, SEM analysis, EDS
and XRD were carried out to determine the swell characteristics and microstructural changes.
Addition of admixture on soil gives a minimum improvement of CBR to a range of 7.5 – 8.5
from 1.4 - 2 for the both the soils used in this study. CBR values also increase with the increase
in curing periods. Free swell index of treated soil reduced by around 50% on addition of FA and
PG in both the soils at the curing period of 7 days. The results obtained from strength test were
compared with SEM investigations, the addition of relatively small amounts of stabilizers shows
noticeable changes in the cementatious formation in soil.

CHAPTER 3
EXPERIMENTAL INVESTIGATION

3.1 Experimental Program Introduction
This chapter provides a detailed description of the materials used in the experimental program
and experimental methods used in this study. The experimental program consists of laboratory
tests on virgin Black cotton soil and mix with molasses to characterize the properties such as
Unconfined Compressive Strength, Swelling Pressure,Differential free Swell
SEM -EDS (scanning electron microscope) test is conducted to know the chemical composition
of Black cotton soil, to study its surface morphology and soil structure.
XRD (x-ray diffraction) test is conducted to detect the presence peak of Montmorillonite mineral
at different diffraction angle and intensity.
3.2 VARIOUS TESTS:
The following tests were performed for present study1.

Casagrande’s Test for liquid limit

2.

Plastic Limit test

3.

SEM-EDS(scanning electron microscopy) for morphology

4.

XRD TEST for determination of montmorillonite mineral

5.

Pycnometer Test for specific gravity

6.

Standard Proctor Test for determination of O.M.C and M.D.D

7.

Unconfined Compressive Strength Test

8.

Differential free swell

9.

Swelling pressure test

10.

Unconsolidated Undrained Triaxial Test

11.

Optum-G2 software for load settlement curve

3.2.1 SEM-EDS Test: An Oven dried sample for 7 days was passed from 75micron sieve to get
the maximum clay minerals for the test. Sample was oven dried properly to make the sample
crystalline and avoid any presence of water molecule during the test. A sample as low as 2gm is
needed for the test.
SEM (Scanning Electron Microscope) test determines the surface morphology of sample by
providing images at various magnifications and EDS is a software which determines the
percentage of various elements available on surface of

the sample magnifications. When

electrons are bombarded on the gold coated soil sample ,the beam is reflected back which gives
images of structural arrangement of sample.SEM has magnification range upto 300000times the
normal image.Gold coating is done on sample to increase conductivity especially on surface to
have better imaging. Non conductive specimens have tendency when bombarded with electron
beam to accumulate electron charge which might cause scanning faults. Therefore, ultrathin gold
coating on specimen with high vacuum evaporation machine.

3.2.2 XRD Test: An Oven dried sample for 7 days was passed from 75micron sieve to get the
maximum clay minerals for the test. Sample was oven dried properly to make the sample
crystalline and avoid any presence of water molecule during the test. A sample as low as 2gm is
needed for the test.

XRD determines the chemical composition of the material in terms of compounds present as well
as constituting elements of the materials.XRD shows the plot between intensity and 2ø angle for
the sample where peaks for the constituting compounds or elements of the sample can be seen at
various angles.

Laboratory tests

Standard/Procedures

Specific gravity

IS: 2720 (Part 3) – 1980

Grain size analysis

IS: 2720 ( Part 4) – 1985

Atterberg limit test

IS: 2720 ( Part 5) – 1985

Differential free swell index

IS: 2720 ( Part 40) – 1977

Standard Proctor compaction test

IS: 2720 ( Part 7) – 1980

Swelling Pressure

IS: 2720 ( Part 41) – 1977

Unconfined compressive strength test

IS: 2720 (Part 10) – 1991

Unconsolidated Undrained Triaxial Test

IS 2720 (Part11) -1993

Table 3.1:Lab test as per Indian Standards
OPTUM-G2 ANALYSIS: It is a Software based on Finite element method program made for
analysis of deformation and stabililty in geotechnical engineering.the software is designed to be
user

friendly

with

efficient

working.It

has

various

modes

of

analysis

like

Elastic,Elastoplastic,Meshing,Limit Analysis,Mohr-Coulumb,Strength Reduction.
Optum

allows

easy

modelling

with

automatically

recognising

intersections,surfaces

etc.Geometrical data along with coordinates may be added with a click of mouse.Autocad files
can be easily imported to the Optum software using DXF file format.Optum Includes various

cases with type of materials having predefined properties like Stifness,Unit weight,Angle of
friction etc.
This Software was used to plot load settlement curve and determine max Stress for footing
constructed on Virgin Black Cotton soil and for optimum Soil mix Proportion(6% molasses).To
get the desired analysis few Geotechnical shear strength parameters were calculated using
unconsoildated Undrained triaxial test .
3.3 Materials used in experimental work:

3.3.1 Black cotton soil: Specimen was collected from Kolhapur district, Maharashtra and
top layer was removed with help of shovel up to depth of 0.5m.The geotechnical properties of
black cotton soil are determined by conducting series of test on soil specimen as shown in table
1.Standard proctor tests were also performed on the virgin soil as well as soil mixes in different
proportions of molasses % by weight of soil (2, 3, 4, 6, 8, 10) to determine OMC and MDD.

Table 3.2:Properties of Black Cotton Soil
Properties

Value

Specific Gravity

2.8

Liquid Limit (%)

57.0

Plastic limit (%)

31.5

Plasticity index (%)

26.5

Differential Free Swell (%)

35.0

Maximum dry density ( kN/m3)

16.1

Unconfined compression strength, (kN/m2)

176.3 KN/m2

3.3.2 MOLASSES: It is black syrupy liquid obtained as by product from sugar industry. It
contains various minerals and vitamins most of it is sugar only. The type of molasses used for the
study is cane molasses. Various physical and chemical properties collected from the factory are
given in table 2 below. The molasses was collected from Budhewal sugar mill, Ludhiana.
Disposal of molasses is of great concern as it increases the PH value of land and makes it unfit
for agriculture purposes. India is the 2nd largest producer of sugar and in the process of sugar
extraction from sugarcane; molasses is produced in huge amount.
Out of every 100tons of sugar cane crushed 4.5 tons of molasses is left as by product.

Table 3.3: Chemical Composition of Molasses
Sr.No.

Chemical Composition

Molasses

1.

Dry matter

73%

2.

Crude protein

4.4

3.

Sugars

45%

4.

Fiber

Nil

5.

Ash

12%

6.

SiO2

0.5%

7.

K2O

3.5%

8.

H2O

6.5%

Source: Budehwal sugar mill,Ludhiana

Table 3.4: Physical Properties of Molasses
S.No.

Physical Properties

Molasses

1.

Colour

Dark Brown

2.

Specific gravity

1.4

3.

Viscosity(cp at 200C)

1500

4.

PH

4.5

5.

Litres/tonne

714

6.

Appearance

Syrupy liquid

7.

Gallons/tonne

157

Source: Budehwal sugar mill,Ludhiana

Water:
According to IS- Code, water to be used for Mixing and Curing should be free from injurious or
deleterious materials and fit for drinking purposes. Portable water is generally considered
satisfactory. In the present investigation, tap water was used for both mixing and curing purposes.

CHAPTER 4
4.1 RESULT AND DISCUSSION
This chapter deals with discussion on results obtained from various tests conducted on soil and its
mix. Results discussed are based on the lab experiments, observations recorded during research
work. Efforts have been made to rectify observation at every level of the study.
Atterberg Limit Test: Liquid limit of specimen soil was 57% and plastic limit 31.5. According
to Unified Soil Classification System (USCS), soil was found to be of highly compressible
nature (CH).

4.2 XRD Test: XRD is fast analytical technique used for identification of crstalline minerals.
X-ray diffraction was performed on selected thin specimen to know chemical composition of the
BC soil and detect presence of montmorillonite mineral which is considered to be the measure
cause of expansive behavior of BC soil. Anode material used was Cu on specimen of length
10mm.The start position of 2 Ø angle was chosen to be 10’ and end position as 80degrees.XRD
shows peaks value of compounds present in the soil sample in form of plot between Intenstiy on
yaxis and 2 Ø on x axis.
2 Ø is the angle at which X-ray beam is bombarded from Copper anode on soil sample(2gm),the
interference between Xray and crystalline sample gives list of compounds along with empirical
formula present in the sample.All results are displayed on the the monitor attached with the XRD
machine in a similar way presented below.

Counts
Black Cotton

Montmorillonite

Montmorillonite

Montmorillonite

500

Montmorillonite

Montmorillonite

1000

0
20

30

40

50

60

70

80

Position [°2Theta] (Copper (Cu))

Fig .4.2 XRD TEST of Virgin Soil Specimen

Visible

*

Compound

Chemical

Semi

Name

Formula

Quant [%]

00-012-

Montmori

Nax ( Al , -

0204

llonite

Mg )2 Si4

Ref. Code

O10 ( O H
)2 ·z H2 O

Discussion of XRD Test


The plot between intensity and 2theta shows presence of MONTMORILLONITE mineral
at various angles along with their peaks (Figure 4.2).

4.2.1 MORPHOLOGY: It is branch of science associated with the structural and formational
study of living & non-living things.SEM instrument was used to get the micrographs of the ovendried sample of virgin soil & soil mixed 6% molasses.
SEM (Scanning Electron Microscope) test determines the surface morphology of sample by
providing images at various magnifications and EDS is a software which determines the
percentage of various elements available on surface of

the sample magnifications. When

electrons are bombarded on the gold coated soil sample ,the beam is reflected back which gives
images of structural arrangement of sample.SEM has magnification range upto 300000times the
normal image.Gold coating is done on sample to increase conductivity especially on surface to
have better imaging. Non conductive specimens have tendency when bombarded with electron
beam to accumulate electron charge which might cause scanning faults. Therefore, ultrathin gold
coating on specimen with high vacuum evaporation machine.

Figure-4.2(a) : Micrograph of untreated soil specimen at 5000 mag.

Figure-4.2(b): Micrograph of untreated soil specimen at 10000 mags.

Figure-4.2(c):Micrograph of untreated soil specimen at 100 mags.


In Micrographs of the untreated sample, the soil structure is visible as loosely packed
blocks due to which there are large void spaces and double diffused layer is wider as
shown in figure 4.2 (a) and figure 4.2(c).

Figure-4.2(d): EDS of untreated soil specimen showing elemental composition

Table 4.2(e):Atomic % of Elements present in Virgin Black Soil Sample
Element

Weight%

Atomic%

CK
OK
Na K
Mg K
Al K
Si K
Ca K
Fe K
Totals

6.79
61.2
0.24
1.44
7.77
16.76
1.14
4.67
100.00

10.35
70.11
0.19
1.08
5.27
10.94
0.52
1.53



The Table shows atomic %age weight of Elemental Composition of Virgin Black Soil in
which
Calcium(Ca),Oxygen(O),Sodium(Na),Magnesium(Mg),Aluminium(Al),Silica(Si),Carbon
(C), Iron(fe) are present.These elements constitute Montmorillonite mineral compound
[Nax ( Al , Mg )2 Si4 O10 ( O H )2 ·z H2 O] which is major cause of expansive
behaviour of Black Soil.



EDS software confirms presence of Montmorillonite mineral in the soil sample.Hence soil
is expansive Black Cotton Soil.

4.2.2Micrographs or SEM images of Black Cotton Soil + 6% molasses

Figure-4.2(e):: Micrograph of treated soil specimen at 100 mags.with 6% molasses

Molasses forms a cementing bond with clay particles as clay particles have occupied vacant
position in soil structure to form a flocculated structure.Molasses promotes ion exhange process
between molasses and clay particles of expansive soil by decreasing thickness of double diffused.


Clay particles becomes coarser in size due to molasses addition.



Angular particles of larger size than Black cotton soil clay particles are observed in SEM
after addition of molasses.

Figure-4.2(f): Micrograph of treated soil specimen at 100 mags.with 6% molasses
Figure 4.2(f): shows non clay minerals and particles like Quartz etc have not formed bond with
molasses.Non clay soil particles seems to have low degree of bonding with molasses.

4.4 Differential free swell: It is the property of expansive soil to govern the Degree of
expansiveness. On the basis of results the soil is found to be highly expansive in nature having
free swell index 35%.

4.5 Standard Proctor Test:As per the test results with increase in percentage of molasses OMC
decreses in soil molasses mix. A different trend is observed in MDD with increasing percent of
molasses MDD keeps decreasing through out the soil mix proportions..OMC rises for 2%
molasses and falls for all other ratio of Soil mix .

Property

S:M0

S:M1

S:M2

S:M3

S:M4

S:M5

Proportion

100:0

98:2

96:4

94:6

92:8

90:10

22.5

23

16

15

12.5

12

1.56

1.47

1.55

1.53

1.50

1.49

Soil:
Molasses

Optimum
Moisture
Content (%)

MDD(gm/cc)

1.57

Max. Dry Density(gm/cc)

1.56
1.55
1.54
1.53
1.52
1.51
1.5
1.49
1.48
1.47
1.46
0

2

4

6

8

Percentage of molasses(%)
Figure 4.5 (a): MDD and %age of molasses

10

12

Discussion of Proctor Test Results:


As specific gravity of molasses(1.4) is less than the Black cotton soil(2.8)
maximum dry density decreases with increasing % of molasses.



As molasses conatins water (6.5%) due to which net water content in the soil
molasses mix rises which decreases dry density of mix.

1.6

Dry Density(gm/cc)

1.55
1.5

100:0 %
98:2%

1.45

96:4%
94:6%

1.4

92:8%
1.35
1.3
0%

5%

10%

15%

20%

Water Content(%)

25%

30%

Figure 4.5 (b): MDD and Water Content(w) for BC at various proportions

4.6 Swelling Pressure Test: The swelling Pressure of soil was found to be 4 kg/cm2.The test
procedure followed for the specified test is as per IS: 2720 ( Part 41) – 1977.With addition of
molasses the swelling pressure of Black cotton soil reduced considerably. The reduction in
swelling pressure is due to increased silt and sand content and less clay content. This is due to the
flocculated soil particles due to the cation exchange process between the cations of molasses and
easily exchangeable cation on soil surface. Molasses has tendency to enhance flocculation and
stability of soil aggregate as it has adhesive properties due to presence of hydroxyl group (OH)
which is mainly responsible for properties of sugar and molasses. Hydrogen bonds are
intermolecular in nature and have net positive charge on them which makes the molasses
adhesive in nature and binds the soil particles together thereby increasing the stability of
expansive clay as clay particles are negatively charged.

Table 4.6: Swelling pressure at various molasses %age
Property

S:M0

S:M1

S:M2

S:M3

S:M4

S:M5

Proportion

100:0

98:2

96:4

94:6

92:8

90:10

4

2.57

1.484

0.21

0. 4

0.45

35.75

62.9

95

90

88.75

Soil: Molasses
Swelling
Pressure
( kg/cm2)
Swell

pressure

reduced (%)

----

% Reduction in Swelling

120
100
80
60

Virgin Soil
Stabilised Soil

40
20
0
Virgin Soil Soil+2%
Molasses

Soil+4%
Molasses

Soil+6%
Molasses

Soil+8% Soil+10%
Molasses Molasses

Figure 4.6(a): % Reduction in Swelling pressure at various molasses %age

4.5

Swelling Pressure(kg/cm2)

4

4

3.5
3
2.57

2.5
2
1.5

1.484

1
0.5

0.5

0.45
0.21

0
0

2

4

6

8

10

Molasses(%)

Figure 4.6 (b): Effect of molasses on swelling pressure of clay

12

4.6.2 Discussion of Swelling pressure results:


With increasing %age of molasses up to 8% swelling pressure shows decline but any
percentage greater than that reduces the ability of molasses to stabilize the Black Cotton
soil. With increasing value of molasses above 8% value of swelling pressure starts
increasing again.



Molasses reduces the amount of montmorillonote mineral either by breaking it into its
constituent elements or by making a more stable less expansive compound with
montmoriilonite mineral.It is predicted by XRD Test as shown below figure 4.(c).Only
one peak of low intensity is left after addition of molasses.

Counts
Black Cotton low angle

6000

4000

m
o
n
t
m
o
r
r
i
l
o
n
i
r
e

2000

0
10

20

30

40

50

Position [°2Theta] (Copper (Cu))

Figure 4.6 (c): Montmorrilonite mineral at 6%molasses + Black Cotton Soil

4.7 Unconfined Compressive Strength Test: The test procedure followed was as per Indian
standard code IS 2720 (Part 10): 1991.The table shown below shows the compressive stress
induced in soil specimen at different strain values. The Unconfined Compressive Strength test is
special form of triaxial test in which confining pressure is zero and the sample is loaded axially.
The test is designed basically for clayey soil with mounted load proving ring and a strain
measuring dial gauge attached to the apparatus .The prerpared mould has dimensions equal to
38mm in diameter and 78mm length wise. Load proving readings and area were measured at
every strain value in multiples of 50.
CALCULATIONS AND PLOTTING:
a) The axial strain, e, shall from the following relationship:
e= ΔL/LO
where L = the change in the specimen length as read from the strain dial indicator,

b) The average cross-sectional area, A, at a particular strain shall be determined from the
following relationship:
A =- Ao / (l-e)
where Ao = the initial average cross-sectional
area of the specimen.
c) σc= P/A
σc = Compressive Stress
P = the compressive force, and
A = average cross-sectional area

UNCONFINED COMPRESSIVE STRENTH (FOR VIRGIN SOIL)
S/ No.

Calculations
Dial gauge
Proving ring
Strain
Reading Deformation Reading Load
ε
(ΔL)
(p) kg =ΔL/L0

Corrected
area
A=A0/(1-ε)
( cm2)

Compressive
stress (σ)=P/A
(kg/cm2)
0.000

0

0

1

0

0

0.000

19.635
0.253

50
2

10
0.5

5

0.006

19.762
0.402

100
3

16
1

8

0.013

19.890
0.687

150
4

27.5
1.5

13.75

0.019

20.020
1.030

200
5

41.5
2

20.75

0.026

20.152
1.171

250
6

47.5
2.5

23.75

0.032

20.285
1.322

300
7

54
3

27

0.038

20.420
1.520

350
8

62.5
3.5

31.25

0.045

20.557
1.631

400
9

67.5
4

33.75

0.051

20.696
1.680

450
10

72.5
4.5

36.25

0.058

20.837
1.716

550
12

77.5
5.5

38.75

0.071

21.125
1.763

600
13

81.5
6

40.75

0.077

Table 4.7(a) – UCS value for virgin soil

21.271

mix (S:M) (2% molasses)
UNCONFINED COMPRESSIVE STRENTH
S/ No.

Calculations
Dial gauge

Proving ring

Strain

Corrected
area
A=A0/(1-ε)

Compressive
stress (σ)=P/A
(kg/cm2)

Reading

Deformation
(ΔL)

Reading

Load
(p)

ε
=ΔL/L0

1

0

0

0

0

0.000

19.635

0.000

2

50

0.5

5

2.5

0.006

19.762

0.127

3

100

1

15

7.5

0.013

19.890

0.377

4

150

1.5

24

12

0.019

20.020

0.599

5

200

2

43

21.5

0.026

20.152

1.067

6

250

2.5

48

24

0.032

20.285

1.183

7

300

3

54

27

0.038

20.420

1.322

8

350

3.5

63

31.5

0.045

20.557

1.532

9

400

4

68

34

0.051

20.696

1.643

10

450

4.5

72.5

36.25

0.058

20.837

1.740

11

500

5

78.5

39.25

0.064

20.980

1.871

12

550

5.5

83

41.5

0.071

21.125

1.965

13

600

6

87

43.5

0.077

21.271

2.045

14

650

6.5

90

45

0.083

21.420

2.101

Table 4.7(b) – UCS value for virgin soil +2%molasses

mix (S:M) (4% molasses)
UNCONFINED COMPRESSIVE STRENTH
S/ No.

Calculations
Dial gauge

Proving ring

Reading Deformation Reading
(ΔL)

Strain

Load
(p)

ε
=ΔL/L0

Corrected
area
A=A0/(1-ε)

Compressive
stress (σ)=P/A
(kg/cm2)

1

0

0

0

0

0.000

19.635

0.000

2

50

0.5

8.75

4.375

0.006

19.762

0.221

3

100

1

18.75

9.375

0.013

19.890

0.471

4

150

1.5

25

12.5

0.019

20.020

0.624

5

200

2

50

25

0.026

20.152

1.241

6

250

2.5

61.25

30.625

0.032

20.285

1.510

7

300

3

75

37.5

0.038

20.420

1.836

8

350

3.5

82.5

41.25

0.045

20.557

2.007

9

400

4

91.25

45.625

0.051

20.696

2.205

10

450

4.5

97.5

48.75

0.058

20.837

2.340

11

500

5

102.5

51.25

0.064

20.980

2.443

12

550

5.5

106.25

53.125

0.071

21.125

2.515

13

600

6

108.75

54.375

0.077

21.271

2.556

14

650

6.5

115

57.5

0.083

21.420

2.684

Table 4.7(c) – UCS value for virgin soil +4%molasses

mix (S:M) (6% molasses)
UNCONFINED COMPRESSIVE STRENTH
S/

Calculations

No.

Dial gauge
Reading

Deformation

Proving ring
Reading

(ΔL)

Strain

Corrected

Compressive

Load

ε

area

stress

(p)

=ΔL/L0

A=A0/(1-ε)

(σ)=P/A
(kg/cm2)

1

0

0

0

0

0.000

19.635

2

50

0.5

9.5

4.75

0.006

19.762

3

100

1

22.5

11.25

0.013

19.890

4

150

1.5

35

17.5

0.019

20.020

5

200

2

45

22.5

0.026

20.152

6

250

2.5

60

30

0.032

20.285

7

300

3

75

37.5

0.038

20.420

8

350

3.5

85

42.5

0.045

20.557

9

400

4

95

47.5

0.051

20.696

10

450

4.5

110

55

0.058

20.837

11

500

5

120

60

0.064

20.980

12

550

5.5

125

62.5

0.071

21.125

13

600

6

127.5

63.75

0.077

21.271

14

650

6.5

129

64.5

0.083

21.420

Table 4.7(d) – UCS value for virgin soil +6%molasses

0.000
0.240
0.566
0.874
1.315
1.541
1.861
2.067
2.295
2.640
2.860
2.959
2.997
3.011

mix (S:M) (8% molasses)
UNCONFINED COMPRESSIVE STRENTH
S/
No.

Calculations
Dial gauge

Proving ring

Strain

Corrected
area
A=A0/(1-ε)

Compressive
stress
(σ)=P/A
(kg/cm2)

Reading

Deformation
(ΔL)

Reading

Load
(p)

ε
=ΔL/L0

1

0

0

0

0

0.000

19.635

0.000

2

50

0.5

9

4.5

0.006

19.762

0.228

3

100

1

20

10

0.013

19.890

0.503

4

150

1.5

32.5

16.25

0.019

20.020

0.812

5

200

2

52.25

26.125

0.026

20.152

1.296

6

250

2.5

62

31

0.032

20.285

1.528

7

300

3

76

38

0.038

20.420

1.861

8

350

3.5

84.5

42.25

0.045

20.557

2.055

9

400

4

92

46

0.051

20.696

2.223

10

450

4.5

100

50

0.058

20.837

2.400

11

500

5

104.5

52.25

0.064

20.980

2.490

12

550

5.5

110.5

55.25

0.071

21.125

2.615

13

600

6

116.25

58.125

0.077

21.271

2.733

14

650

6.5

120

60

0.083

21.420

2.801

Table 4.7(e) – UCS value for virgin soil +8%molasses

mix (S:M) (10% molasses)
UNCONFINED COMPRESSIVE STRENTH
S/
No.

Calculations
Dial gauge

Proving ring

Strain

Corrected
area
A=A0/(1-ε)

Compressive
stress
(σ)=P/A
(kg/cm2)

Reading

Deformation
(ΔL)

Reading

Load
(p)

ε
=ΔL/L0

1

0

0

0

0

0.000

19.635

0.000

2

50

0.5

7.5

3.75

0.006

19.762

0.190

3

100

1

17

8.5

0.013

19.890

0.427

4

150

1.5

26

13

0.019

20.020

0.649

5

200

2

45.5

22.75

0.026

20.152

1.129

6

250

2.5

55

27.5

0.032

20.285

1.356

7

300

3

65.5

32.75

0.038

20.420

1.604

8

350

3.5

75

37.5

0.045

20.557

1.824

9

400

4

82.5

41.25

0.051

20.696

1.993

10

450

4.5

90

45

0.058

20.837

2.160

11

500

5

100

50

0.064

20.980

2.383

12

550

5.5

104.5

52.25

0.071

21.125

2.473

13

600

6

107

53.5

0.077

21.271

2.515

14

650

6.5

110

55

0.083

21.420

2.568

Table 4.7(f) – UCS value for virgin soil +10%molasses

3.5

3

2.5

2

10% molasses

Stress
(Kg/cm2)

8% molasses
6% molasses
1.5

4% molasses
2% molasses
virgin soil

1

0.5

0
0

0.02

0.04

0.06

0.08

0.1

Strain

Figure 4.7(a) Stress –Strain Curve for Soil-Molasses mix for all proportions

3.5
3.011

3

2.801

UCS Value (Kg/cm2)

2.684

2.589

2.5
2.101

2
1.763
1.5
1
0.5
0
0

2

4

6

8

10

12

Molasses Percentage(%)
Figure 4.7(b) UCS value & %ages of molasses added to Black Soil

4.7.2 Discussion of UCS Test Results:
With increase in percentage of molasses maximum dry density decreased but UCS value
increased.It may be due to Molasses acts as a adhesive having net positive charge on its
constituting Hydroxyl group (OH) which helps form a better bond with negative charged clay
particles. Molasses also decreases thickness of double diffused layer which allows the clayey
particles to exchange ions and flocculate easily which is also the cause of increased UCS value
due to molasses addition.
Maximum value of UCS was observed at 6% molasses mix with soil specimen.molasses
increased the cohesion value of soil therby increasing UCS strength of soil.Up to 6% additon of

molasses specimen showed increase in strength which started decline there after.At 8 % soilmolasses mix a value slightly lesser than maximum UCS value was observed but after that
decline was considerable.
As clearly visible from the results of Unconfined Compressive test Results that molasses alone is
capable of reducing swell pressure and increasing strength up to 70%.While conducting the UCS
test no curing was done as molasses is soluble in water.UCS prepared sample for virgin as well as
molasses mix specimen were casted in mould and tested for UCS strength immediately. Molasses
reduces the pH of soil which is indication of cation exchange process started at the surface, pH
reduction is also indication that soil changed from neutral to slightly acidic..

4.8 OPTUM-G2 ANALYSIS: Unconsolidated undrained Triaxial test performed on virgin soil
at different confining pressures 1kg/cm2 ,2kg/cm2 and 3kg/cm2 for 3 samples helped in finding
out geotechnical engineering parameters(E,c, Ø, ų).These parameters when used in Optum G2
gave load settlement curve,point of max stress and value of max stress for black cotton soil.
In the analysis of footing on black cotton soil settlement assumed was along y axis maintaing the
case of standard fixities on x axis.No Water table was assumed below the ground level.The
analysis type used was multiplier elastoplastic where load is increased on soil mass until it fails.

Figure 4.8 (a)Mohr Circle for Black Cotton soil Obtained from Triaxial test

Figure 4.8 (b)Mohr Circle for Black Cotton + 6% molasses soil Obtained from Triaxial test

Soil:Molasses

E(MPa)

C(kn/m2) Ø(degree)

Ų(poisson’s

Dry density(Yd )

ratio)

Kn/m3

Ko

(100:0)%

4

10.3

12.52

0.33

15.6

0.8

(94:6)%

6

13.69

20.10

0.4

15.3

0.8

Table 4.8.1 Inputs used for Numerical Modelling

Numerical Modelling in Optum G2-Modelling is to stimulate a square foundation 2m x 2m
constructed on Black cotton soil of high compressibility.The foundation was subjected to
multiplying load in –ve y axis with initial value of 1kn/m2.The Load – Displacement analysis is
based on mohr-coloumb soil model and interface is assumed as Noassociated between Black
cotton soil and foundation.The non associated interface ensures whole stress has been transferred
from foundation to soil particles. Elemental mesh consists of triangular element each with 6
nodes.Water table has been assumed at 1.25m below the footing.
The analysis was based on mechanical and physical geoengineering parameters like
cohesion(c),Poission’s ratio(Ų),Friction angle(Ø),Young’s modulus(E) obtained from Triaxial
UU test to approach closely a actual state.It is assumed that soil base will have elastoplastic
behaviour under increament of loads with different values of stress for varying deformations.

Figure 4.8(c) Cross sectional view of Numerical Model

0.000
0.000

-0.050

-0.100

-0.150

-0.200

-0.250

-0.300

-0.350

-0.400

-100.000

Stress (Kn/m2)

-200.000

-300.000

-400.000

Virgin soil
Black Soil + 6% Molasses

-500.000

-600.000

-700.000

Displacement (m)

Figure 4.8 (d)Comparison of Stress-Displacemnt curve Obtained from Optum G2

4.8.1 Discussion of Optum G2 Test Results


From Stress Displacement curve figure4.8(d) it was observed that the load bearing
capacity increases from 256 Kpa to 570Kpa when Black

soil was mixed with

6%molasses as compared to virgin Black soil.


Incresed Failure stress value for the optimum mix(6% molasses) is due to increase in
friction & bonding between particles of stabilised soil.Particles increase in size due to
addition of molasses and it reduces overall voids in the soil.



With increase in percentage of molasses maximum dry density decreased but UCS value
increased.It may be due to Molasses acts as a adhesive having net positive charge on its
constituting Hydroxyl group (OH) which helps form a better bond with negative charged
clay particles. Molasses also decreases thickness of double diffused layer which allows
the clayey particles to exchange ions and flocculate easily which is also the cause of
increased UCS value due to molasses addition.

CHAPTER 5
CONCLUSION
5.1 Following conclusions are obtained from the study