International Journal of Science and Engineering Research ...Coconut Coir Sodium Chloride (NaCl)...
Transcript of International Journal of Science and Engineering Research ...Coconut Coir Sodium Chloride (NaCl)...
International Journal of Science and Engineering Research (IJ0SER),
Vol 2 Issue 7 july-2014
Shahabas banu. . . . (IJ0SER) July- 2014
Experimental Investigation Of Soil Stabilization
shahabas banu.s M.E structural engineering
J.C.T College Of Engineering And Technology
Coimbatore, Tamilnadu,India.
*
Abstract— Clays exhibit generally undesirable engineering properties. They tend to have low shear strengths and to lose shear
strength further upon wetting or other physical disturbances. They can be plastic and compressible and they expand when wetted and
shrink when dried. Some types expand and shrink greatly upon wetting and drying – a very undesirable feature. Cohesive soils can
creep over time under constant load, especially when the shear stress is approaching its shear strength, making them prone to sliding.
They develop large lateral pressures. They tend to have low resilient modulus values. For these reasons, clays are generally poor
materials for foundations. The annual cost of damage done to non-military engineering structures constructed on expansive soils is
estimated as many billions of dollars worldwide. Many admixtures are successfully used for stabilizing expansive clays. The strength
characteristics of stabilized clays are measured by means of unconfined compressive strength (UCS) or California Bearing Ratio
(CBR) values. Depending upon the soil type, the effective admixtures content for improving the engineering properties of the soil is
varied.
Keywords— California Bearing Ratio, Cohesive soils, Proctor Compaction Test, specific gravity.
I. INTRODUCTION
Soil stabilization refers to the procedure in which a special
soil, a cementing material, or other chemical material is added
to a natural soil to improve one or more of its properties. One
may achieve stabilization by mechanically mixing the natural
soil and stabilizing material together so as to achieve a
homogeneous mixture or by adding stabilizing material to an
undisturbed soil deposit and obtaining interaction by letting it
permeate through soil voids. Where the soil and stabilizing
agent are blended and worked together, the placement process
usually includes compaction. Soil stabilizing additives are
used to improve the properties of less–desirable rood soils. When used these stabilizing agents can improve and maintain
soil moisture content, increase soil particle cohesion and serve
as cementing and water proofing agents.
A difficult problem in civil engineering works exists when
the sub-grade is found to be clay soil. Soils having high clay
content have the tendency to swell when their moisture
content is allowed to increase. Many research have been done
on the subject of soil stabilization using various additives, the
most common methods of soil stabilization of clay soils in pavement work are cement and lime stabilization. The high
strengths obtained from cement and lime stabilization may not
always be required, however, and there is justification for
seeking cheaper additives which may be used to alter the soil
properties.
A. OBJECTIVE
Soils are highly susceptible to volume and strength changes
and hence can cause severe roughness and accelerate the
detoriation of the pavement structure in the form of increased
cracking and decreased ride quality, when combined with
truck traffic. In some cases, the sub grade soils can be treated
with various materials to improve the strength and stiffness
characteristics of the soil.
This thesis investigates the potential of using
vegetable fiber such as coir in ground engineering
applications. In order to better understand the role of
reinforcing material (coir) in improving the strength sub grade pavement, an attempt is made in this
present study with the following objectives.
To find the most efficient way of using coir fibers to
reinforce the available soil sample, since its
environmental and financial advantages are
considerable.
Effect of change of percentage fiber content on the
engineering properties of compacted soil
II. REQUIREMENTS OF SOIL STABILISATION
Every stabilization process will be satisfactory when
it provides required qualities and fulfills the
following criteria:
(1) Be compactable with soil material
(2) Be permanent
(3) Be easily handled and processed
(4) Cheap and safe
International Journal of Science and Engineering Research (IJ0SER),
Vol 2 Issue 7 july-2014
Shahabas banu. . . . (IJ0SER) July- 2014
A. MECHANICAL STABILISATION:
Mechanical stabilization involves two operations,
(a) Changing the composition of the soil by addition or
removal of certain constituents
(b) Densification or compaction
B. CEMENT STABILISATION:
The soil stabilized with Portland cement is known as soil
cement. The cementing action is believed to be result of
chemical reaction of cement with the silicous soil during
hydration. The binding action individual particles through
cement may be possible only in coarse – grained soils. In fine grained, cohesive soils, only some of the particles have
expected to have cement bonds, and rest will be bonded
through natural cohesion.
C. LIME STABILISATION
Hydrated (or slaked) lime is very effective
in treating heavy, plastic, clayey, soils. Lime may be used
alone or in combination with cement, bitumen, or fly ash.
Sandy soils can also be stabilized with these combinations.
Lime has been mainly used for stabilizing the road bases and sub- grades.
On addition of lime to soil, two main types
of chemical reactions occur:
(a) Alteration in the nature of the absorbed
layer through base exchange phenomenon
(b) Cementing or pozzolanic action.
III. STABILIZER
The admixtures that added to the soil to improve its
engineering performance are termed as stabilizers.
A. TYPES OF STABILIZERS
The types of stabilizers used are,
Coconut Coir
Sodium Chloride (NaCl)
Rice Husk Ash
B. COCONUT COIR
Coir is a natural fiber extracted from the husk of
coconut and used in products such as floor mats, doormats,
brushes, mattresses etc. Technically coir is the fibrous
material found between the hard, internal shell and the outer
coat of a coconut. Other uses of brown coir (made from ripe coconut) are in upholstery padding, sacking and horticulture.
White coir is harvested from unripe coconuts, and is used for
making finer brushes, string, rope and fishing nets.
Total world coir fiber production is 250,000 tonne (250,000
long tons; 280,000 short tons). The coir fiber industry is
particularly important in some areas of the developing world.
India, mainly in Pollachi 40% and the coastal region of Kerala
State, produces 20% of the total world supply of white coir
fiber. Sri Lanka produces annually throughout the world of
consumed in the countries of origin, mainly India. Together
India and Sri Lanka produce 90% of the 250,000 metric tons
of coir produced every year.
C PHYSICAL PROPERTIES OF COIR:
The physical appearance and quality of the fibers varies
widely. The color of the fiber is not influenced by the species
of the nut from which it is derived but also its maturity, time
lapse between dehusking and retting etc. However under identical conditions of these variables, the fibers extracted
from infant nuts exhibit a pale yellow color. The intensity of
color and thickness increase with age and the fibers are
remarkably stiff and posses good extensibility.
Morphologically, coir is a multi cellular fiber with 12 to 24
microns in diameter and the ratio of length to thickness is
observed to be 35.
D. SODIUM CHLORIDE
The stabilizing action of chloride is somewhat to that of calcium chloride, but it has not been so widely used. It attracts
and retains moisture and reduces the rate of evaporation.
Another beneficial phenomenon is the crystallization of the
salt in the soil pores near the surface, which retards further
evaporation and also reduces the formation of shrinkage
cracks.
E. RICE HUSK ASH
Rice Husk Ash (RHA) is obtained from the
burning of rice husk. The husk is a by-product of the rice milling industry. By weight, 10% of the rice grain is rice husk.
On burning the rice husk, about 20% becomes RHA
F. CHEMICAL COMPOSITION OF RICE HUSK ASH
Silica – SiO2 90.23%
Alumina – Al2O3 2.54%
Carbon 2.23%
Calcium Oxide – CaO 1.58%
Magnesium Oxide – MgO 0.53%
Potassium Oxide – KaO 0.39%
Ferric Oxide – Fe2O3 0.21%
G. SOIL SAMPLE
The soil sample is clay soil which is distributed in most of
the places around the coast of Bay of Bengal. A disturbed soil
sample is that in which a natural structure of soil get partly or
fully modified and is destroyed although with suitable
precautions for natural moisture content may be preserved.
Such a sample is called as representative soil sample. The representative soil sample for the thesis was collected
from a construction site near Pondicherry and it was analyzed
for its strength properties. An open pit was made up to a depth
of 1.5m below the ground surface where the representative
soil samples were taken.
International Journal of Science and Engineering Research (IJ0SER),
Vol 2 Issue 7 july-2014
Shahabas banu. . . . (IJ0SER) July- 2014
H. LABORATORY EXPERIMENTS
The following laboratory experiments are performed as per
IS Specifications.
Specific Gravity
Sieve analysis (particle size distribution)
Atterberg’s limits (liquid limit, plastic limit)
Standard proctor compaction test (maximum dry
density and optimum moisture content)
Unconfined Compression Strength test.
III. EXPERIMENTAL INVESTIGATION
A. PARTICLE SIZE DISTRIBUTION OF VIRGIN SOIL SAMPLE
The dried sample is taken in a tray, soaked in water and
mixed with either 2g of sodium hexametaphosphate or 1g of
sodium hydroxide and 1g of sodium carbonate per liter of
water, which is added as a dispersive agent. The soaking of
soil is continued for 10 to 12hrs. The sample is washed
through 4.75mm IS Sieve with water till substantially clean
water comes out. Retained sample on 4.75mm IS Sieve should
be oven-dried for 24hrs. This dried sample is sieved through
20mm and 10mm IS Sieves.
Weight of Soil taken, g = 2000g
IS
Sieve
Particle
Size D
(mm)
Mass
retained
(g)
%
retained
Cumulative %
retained
%
finer
(N)
4.75 mm
4.75 1416 70.8 70.8 29.2
2.36
mm
2.36 144 7.2 78 22
1.18 mm
1.18 183 9.15 87.15 12.85
600 µ 0.6 118 5.9 93.05 6.95
300 µ 0.3 81 4.05 97.1 2.9
90 µ 0.09 42 2.1 99.2 0.8
75 µ 0.075 4 0.2 99.4 0.6
Pan Pan 12 0.6 100 0
B. SPECIFIC GRAVITY OF VIRGIN SOIL SAMPLE
Specific gravity is the ratio of the weight in air of a given
volume of a material at a standard temperature to the weight
in air of an equal volume of distilled water at the same stated
temperature
Weight of Soil taken, g = 500g
C. LIQUID LIMIT OF VIRGIN SOIL SAMPLE
Air-dry the soil sample and break the clods. Remove the
organic matter like tree roots, pieces of bark, etc. About 100g
of the specimen passing through 4.75mm IS Sieve is mixed
thoroughly with distilled water in the evaporating dish and left for 24hrs for soaking.
Natural water content, wt = 0.76%
Determination Trails
1 2 3
No. of blows 33 27 21
Container No. I II III
Wt of container (w0) g 19.15 19.23 19.73
Wt of container + wet soil (w1) g
25.83 35.74 36.12
Wt of container + oven dried soil (w2) g
23.01 28.7 29.02
Water content = (w1-w2)/(w2-w0) x 100%
73.06% 74.34% 76.43%
Water content 74.61%
D. PLASTIC LIMIT OF VIRGIN SOIL SAMPLE
Take out 30g of air-dried soil from a thoroughly mixed
sample of the soil passing through 4.75mm IS Sieve. Mix the soil with distilled water in an evaporating dish and leave the
soil mass for maturing.
Natural water content, wt = 0.76%
E. STANDARD PROCTOR COMPACTION TEST
Soil not susceptible to crushing during compaction a 5kg
sample of air-dried soil passing through the 19mm IS Sieve
should be taken. The sample should be mixed thoroughly
with a suitable amount of water depending on the soil type (for sandy and gravelly soil - 3 to 5% and for cohesive
soil - 12 to 16% below the plastic limit).
Specific Gravity of soil 1.952
Amount of compaction Light
Determinations Trails
1 2 3 Mass of pycnometer (M1) g 667
Mass of pycnometer + Dry soil (M2) g
1167 1167 1167
Mass of pycnometer + Soil + Water (M3) g
1800 1789 1812
Mass of pycnometer + Water (M4) g
1551 1562 1558
Specific Gravity G=(M2-M1)/[(M2-M1)-(M3-M4)]
1.992 1.832 2.033
Average Specific Gravity 1.952
Determination Trails
1 2 3
Container No. IV V VI
Wt of container (w0) g 21.7 20.15 22.37
Wt of container + wet soil (w1) g
29.41 28.38 31.59
Wt of container + oven dried soil (w2) g
26.6 25.4 28.2
Water content = (w1-w2)/(w2-w0) x 100%
57.35% 56.76% 58.15%
Water content 57.42%
International Journal of Science and Engineering Research (IJ0SER),
Vol 2 Issue 7 july-2014
Shahabas banu. . . . (IJ0SER) July- 2014
Volume of the mould (V) cc 997.45 cc
Wt of the mould + Base plate (W1) 4.301 Kg
Fig. 1 optimum water content
Optimum moisture content by graph 20.49%
Maximum dry density by graph 1.713 g/cc
F. COMPACTION TEST OF SOIL AFTER ADDING COIR
The samples were prepared in dry condition by mixing
required quantity of coir fiber with soil. Coir fiber to be added
was worked out based on the dry weight of the soil.
1. COMPACTION TEST OF SOIL AFTER ADDING 0.5%
COIR
Fig. 2 optimum water content for adding 0.5% of coir
Optimum moisture content by graph 22.53%
Maximum dry density by graph 2.485g/cc
2. COMPACTION TEST OF SOIL AFTER ADDING 1%
COIR
Fig. 3 optimum water content for adding 1 % of coir
Optimum moisture content by graph 22%
Maximum dry density by graph 2.485 g/cc
Determination Trail
1 2 3 4 5 6
Wt of mould +
Compacted soil (W2) Kg
5.982 6.089 6.17 6.218 6.28 6.351
Wt of compacted soil W, Kg
1.681 1.788 1.869 1.917 1.979 2.05
Wet density γb
= (W/V) g/cc
1.685 1.793 1.874 1.922 1.984 2.055
Water content (w) %
10% 12% 14% 16% 18% 20%
Dry density γd = γb/(1+w)
1.532 1.601 1.644 1.657 1.681 1.713
Dry density at zero voids, γd
= Gγw/(1+wG)
1.633 1.582 1.533 1.487 1.444 1.404
Determinati
on
Trails
1 2 3 4 5 6
Container No.
I II III IV V VI
Wt of container (w0) g
15.98 16.1 15.68
15.72
15.63
15.92
Wt of container + wet soil (w1) g
24.62 25.43
24.3 24.21
24.27
24.27
Wt of container + oven dried soil (w2) g
23.81 24.42
23.23
23.01
22.93
22.85
Water content = (w1-w2)/(w2-w0) x 100%
10.34%
12.14%
14.17%
16.46%
18.36%
20.49%
International Journal of Science and Engineering Research (IJ0SER),
Vol 2 Issue 7 july-2014
Shahabas banu. . . . (IJ0SER) July- 2014
3. COMPACTION TEST OF SOIL AFTER ADDING 1.5%
COIR
Fig. 4 optimum water content for adding 1.5% of coir
Optimum moisture content by graph 22.29%
Maximum dry density by graph 2.485 g/cc
G. COMPACTION TEST OF SOIL AFTER ADDING NaCl
The samples were prepared in dry condition by mixing
required quantity of NaCl with soil. NaCl to be added was
worked out based on the dry weight of the soil.The
representative soil is mixed with 10%, 15% and 20% of NaCl
and tests were conducted in laboratory.
1.COMPACTION TEST OF SOIL AFTER ADDING 10% NaCl
Fig. 5 optimum water content for adding 10% of NACL
Optimum moisture content by graph 12.14%
Maximum dry density by graph 2.485 g/cc
2.COMPACTION TEST OF SOIL AFTER ADDING 15%
NaCl
Fig. 6 optimum water content for adding 15% of NACL
Optimum moisture content by graph 12.68%
Maximum dry density by graph 1.892g/cc
3.COMPACTION TEST OF SOIL AFTER ADDING 20%
NaCl
Fig. 7 optimum water content for adding 20 % of NACL
Optimum moisture content by graph 12.41%
Maximum dry density by graph 2.485 g/cc
H. COMPACTION TEST OF SOIL AFTER ADDING RICE
HUSK ASH
The samples were prepared in dry condition by mixing
required quantity of Rice husk ash with soil. Rice husk ash to
be added was worked out based on the dry weight of the soil.
The representative soil is mixed with 5%, 7.5% and 10% of
Rice husk ash and tests were conducted in laboratory.
International Journal of Science and Engineering Research (IJ0SER),
Vol 2 Issue 7 july-2014
Shahabas banu. . . . (IJ0SER) July- 2014
1.
COMP
ACTI
ON TEST OF SOIL AFTER ADDING 5% RICE HUSK ASH
Optimum moisture content by graph 18.36%
Maximum dry density by graph 2.485 g/cc
2. COMPACTION TEST OF SOIL AFTER ADDING 7.5%
RICE HUSK ASH
Fig. 9 optimum water content for adding7.5% of ricehusk
3. COMPACTION TEST OF SOIL AFTER ADDING 10% RICE HUSK ASH
Fig. 10 optimum water content for adding7.5% of rice husk
Optimum moisture content by graph 18.31%
Maximum dry density by graph 2.485 g/cc
I. UNCONFINED COMPRESSIVE STRENGTH
The initial length, diameter and weight of the specimen
shall be measured and the specimen placed on the bottom
plate of the loading device. The upper plate shall be adjusted
to make contact with the specimen. The deformation dial
gauge shall be adjusted to a suitable reading, preferably in multiples of 100.
Force shall be applied so as to produce axial strain at a rate
of 0.5 to 2 percent per minute causing failure with 5 to 10.
The force reading shall be taken at suitable intervals of the
deformation dial reading.
The angle between the failure surface and the horizontal
may be measured, if possible, and reported. The water content
of the specimen shall be determined in accordance with IS 2720 (Part 2): 1973 using samples taken from the failure zone
of the specimen.
TABLE I
FONT SIZES FOR PAPERS
Optimum moisture content by graph 22.29%
Maximum dry density by graph 2.485g/cc
Weight of sample 250g
Water content 20%
Diameter 38mm
Length 76mm
Area 1133.54 mm2
Deform
ation
dial
gauge
reading
1div=0.0
1mm
Defor
mation
ΔL
(mm)
Force
(F)
x103
N
Strain
∑=ΔL/
L
Area
A=A0/(
1-∑)
x103m
m2
Stress
(P/A)
N/mm2
50 0.2 1 0.0026 1.137 0.880
100 0.2 1 0.0026 1.137 0.880
150 0.3 1.5 0.0039 1.138 1.318
200 0.4 2 0.0053 1.140 1.755
250 0.5 2.5 0.0066 1.141 2.191
300 0.6 3 0.0079 1.143 2.626
350 0.7 3.5 0.0092 1.144 3.059
400 0.9 4.5 0.0118 1.147 3.923
450 1 5 0.0132 1.149 4.353
500 1.2 6 0.0158 1.152 5.210
550 1.3 6.5 0.0171 1.153 5.636
600 1.5 7.5 0.0197 1.156 6.486
650 1.6 8 0.0211 1.158 6.909
700 1.8 9 0.0237 1.161 7.752
750 2 10 0.0263 1.164 8.590
UCC strength of the sample 4.104 N/mm2
Unit Cohesion, c 4.295 N/mm2
International Journal of Science and Engineering Research (IJ0SER),
Vol 2 Issue 7 july-2014
Shahabas banu. . . . (IJ0SER) July- 2014
A. UCC STRENGTH OF SOIL AFTER ADDING COIR
The samples were prepared in dry condition by mixing
required quantity of coir fiber with soil. Coir fiber to be added
was worked out based on the dry weight of the soil. The
samples for unconfined compression test, consists of coir fiber mixed in dry soil and compacted at optimum moisture content
(OMC) found out by conducting Standard Proctor compaction
Test under varying percentages of coir. The representative soil
is mixed with 0.5%, 1% and 1.5% of coir fiber and tests were
conducted in laboratory.
1. UCC STRENGTH OF SOIL AFTER ADDING 0.5% COIR
Water content =22%
2. UCC STRENGTH OF SOIL AFTER ADDING 1% COIR
3. UCC STRENGTH OF SOIL AFTER ADDING 1.5% COIR
UCC strength of the sample 5.641 N/mm2
Unit Cohesion, c 4.712 N/mm2
B. UCC STRENGTH OF SOIL AFTER ADDING NaCl
The samples were prepared in dry condition by
mixing required quantity of NaCl with soil. NaCl to be added
was worked out based on the dry weight of the soil. The
representative soil is mixed with 10%, 15% and 20% of NaCl
and tests were conducted in laboratory.
1. UCC STRENGTH OF SOIL AFTER ADDING 10% NaCl
Water content =12%
UCC strength of the sample 5.499 N/mm2
Unit Cohesion, c 4.712 N/mm2
UCC strength of the sample 5.162 N/mm2
Unit Cohesion, c 4.086 N/mm2
UCC strength of the sample 5.611 N/mm2
Unit Cohesion, c 4.712 N/mm2
International Journal of Science and Engineering Research (IJ0SER),
Vol 2 Issue 7 july-2014
Shahabas banu. . . . (IJ0SER) July- 2014
2. UCC STRENGTH OF SOIL AFTER ADDING 15% NaCl
3. UCC STRENGTH OF SOIL AFTER ADDING 20% NaCl
UCC strength of the sample 6.006 N/mm2
Unit Cohesion, c 4.919N/mm2
C.UCC STRENGTH OF SOIL AFTER ADDING RICE HUSK
ASH
The samples were prepared in dry condition by
mixing required quantity of Rice husk ash with soil. Rice husk ash to be added was worked out based on the dry weight of
the soil. The samples for unconfined compression test,
consists of Rice husk ash mixed in dry soil and compacted at
optimum moisture content (OMC) found out by conducting
Standard Proctor compaction Test under varying percentages
of Rice husk ash. The representative soil is mixed with 5%,
7.5% and 10% of Rice husk ash and tests were conducted in
laboratory.
1. UCC STRENGTH OF SOIL AFTER ADDING 5% RICE
HUSK ASH
Water content =12%
UCC strength of the sample 4.818 N/mm2
Unit Cohesion, c 4.086 N/mm2
2. UCC STRENGTH OF SOIL AFTER ADDING 7.5% RICE HUSK ASH
3. UCC STRENGTH OF SOIL AFTER ADDING 10% RICE
HUSK ASH
UCC strength of the sample 5.613 N/mm2
Unit Cohesion, c 4.712 N/mm2
UCC strength of the sample 4.875 N/mm2
Unit Cohesion, c 4.086 N/mm2
International Journal of Science and Engineering Research (IJ0SER),
Vol 2 Issue 7 july-2014
Shahabas banu. . . . (IJ0SER) July- 2014
UCC strength of the sample 4.988 N/mm2
Unit Cohesion, c 4.295 N/mm2
IV. RESULT
TEST COMPARISONS
COMPACTION FACTOR TEST
G. COMPACTION TEST
The relation between dry density and moisture
content for different stabilizers (rice husk ash,
coconut coir, common salt) are plotted.
The addition of stabilizers to the soil increased the
dry density and optimum moisture content of soil.
H. UNCONFINED COMPRESSIVE STRENGTH
II. CONCLUSIONS
UNCONFINED COMPRESSION TEST
The unconfined compressive stress-strain
relationships of specimens, with different
stabilizers and different moisture percentages are
plotted. The unconfined compressive strength increase
with the increase in the compaction effort and
addition of stabilizers.
TEST REPORT
International Journal of Science and Engineering Research (IJ0SER),
Vol 2 Issue 7 july-2014
Shahabas banu. . . . (IJ0SER) July- 2014
By the addition of stabilizers alters the properties
of the sample.
The strength increases with increase in the
percentage of stabilizers.
The addition of coconut coir to the soil causes
hardening and more strength as compared to the
other additives.
REFERENCES
A. Books And Is-Codes
[1] B.C.Punmia &Ashok K. Jain, “Soil Mechanics and Foundation
Engineering” Laxmi Publications..
[2] “Ground Improvement Techniques” S.Purusothama Raj, Laxmi
Publications
[3] Indian Standards METHODS OF TEST FOR SOILS (Second
Revision) IS: 2720 (Part 1 to Part 41) - 1983, Indian Standards
Institution, April 1984, New Delhi.
[4] Indian Standards METHODS OF TEST FOR STABILIZED IS: 4332
(Part 2 to Part 10) - 1967, Indian Standards Institution, January 1968,
New Delhi.
[5] Indian Standards GLOSSARY OF TERMS AND SYMBOLS (First
Revision) IS: 2809 - 1972, Indian Standards Institution, September
1972, New Delhi.
[6] National Building Code.
shahabas banu She is percusing M.E structural engineering in J.C.T college of Engg. & Tech., Coimbatore. She completed her B.E.(civil) in Nehru institute of technology, Coimbatore