480 Mallika, B. Ganesh International Journal of Engineering Technology Science and Research IJETSR www.ijetsr.com ISSN 2394 – 3386 Volume 4, Issue 10 October 2017 Study On Effect Of Chemical Stabilizing Agents On Strength And Swelling Properties Of Soils Mallika 1 , B. Ganesh 2 1 M.Tech student (14961D87 ), Lenora Engineering college, Rampachodavaram, A.P, India 2 Assistant Professor, Department of Civil Engineering, Lenora Engineering College, Rampachodavaram, A.P, India ABSTRACT In India, expansive soils popularly known as black cotton soils are highly problematic, as they swell on absorption of water and shrink on evaporation thereof. Because of this alternate swell and shrinkage, distress is caused to the foundations of structures laid on such soils. Understanding the behavior of expansive soil and adopting the appropriate control measures have been great task for the geotechnical engineers. Proper characterization and selection of suitable foundation is essential in case of problematic soils. Extensive research is going on to find the solutions to black cotton soils. There have been many methods available to control the expansive nature of the soils. Treating the expansive soil with electrolytes are one of the technique to improve the behavior of the expansive ground. Hence, in the present work, experimentation is carried-out to investigate the influence of electrolytes like calcium chloride and ferric chloride on the properties of expansive soil. A methodical process, involving experimentation in the laboratory under controlled conditions is done. With addition of electrolytes to the expansive soil, improvement in its physical and engineering properties is observed. It is observed that the maximum improvement in properties of expansive soil is obtained for Ferric Chloride treatment compared to other electrolytes tried in this investigation Key words: Calcium chloride and ferric chloride Electrolytes, black cotton soil, Ferric Chloride. 1. INTRODUCTION Expansive soil is one among the problematic soils that has a high potential for shrinking or swelling due to change of moisture content. Expansive soils can be found on almost all the continents on the Earth. Destructive results caused by these soils have been reported in many countries. In India, large tracts are covered by expansive soils known as black cotton soils. The major area of their occurrence is the south Vindhyachal range covering almost the entire Deccan Plateau. These soils cover an area of about 200,000 square miles and thus form about 20% of the total area of India. To a large extent they are found in regions having low to medium slope and poor drainage conditions. The primary bed rock is basalt or trap and in some locations quartizites, schists and sedimentary rocks are found. It is expensive in nature due to the presence of montmorillonite and illite clay minerals. Some of these black cotton soils are also found to contain high amount of carbonates. The depth of black cotton soils can be as high as 20m. The primary problem that arises with regard to expansive soils is that deformations are significantly greater than the elastic deformations and they cannot be predicted by the classical elastic or plastic theory. Movement is usually in an uneven pattern and of such a magnitude to cause extensive damage to the structures resting on them. Proper remedial measures are to be adopted to modify the soil or to reduce its detrimental effects if expansive soils are indentified in a project. The remedial measures can be different for planning and designing stages and post construction stages. Many stabilization techniques are in practice for improving the expansive soils in which the characteristics of the soils are altered or the problematic soils are removed and replaced which can be used alone or in conjunction with specific design alternatives. Additives such as lime, cement, calcium chloride, rice husk, fly ahs etc. are also used to alter the characteristics of the expansive soils. The effect of the additives and the optimum amount of additives to be used are dependent mainly on the mineralogical
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480 Mallika, B. Ganesh
International Journal of Engineering Technology Science and Research
IJETSR
www.ijetsr.com
ISSN 2394 – 3386
Volume 4, Issue 10
October 2017
Study On Effect Of Chemical Stabilizing Agents On Strength
And Swelling Properties Of Soils
Mallika1, B. Ganesh2 1M.Tech student (14961D87 ), Lenora Engineering college, Rampachodavaram, A.P, India
2Assistant Professor, Department of Civil Engineering,
Lenora Engineering College, Rampachodavaram, A.P, India
ABSTRACT
In India, expansive soils popularly known as black cotton soils are highly problematic, as they swell on absorption of
water and shrink on evaporation thereof. Because of this alternate swell and shrinkage, distress is caused to the
foundations of structures laid on such soils. Understanding the behavior of expansive soil and adopting the appropriate
control measures have been great task for the geotechnical engineers. Proper characterization and selection of suitable
foundation is essential in case of problematic soils. Extensive research is going on to find the solutions to black cotton
soils. There have been many methods available to control the expansive nature of the soils. Treating the expansive soil
with electrolytes are one of the technique to improve the behavior of the expansive ground. Hence, in the present work,
experimentation is carried-out to investigate the influence of electrolytes like calcium chloride and ferric chloride on the
properties of expansive soil. A methodical process, involving experimentation in the laboratory under controlled
conditions is done. With addition of electrolytes to the expansive soil, improvement in its physical and engineering
properties is observed. It is observed that the maximum improvement in properties of expansive soil is obtained for
Ferric Chloride treatment compared to other electrolytes tried in this investigation
Key words: Calcium chloride and ferric chloride Electrolytes, black cotton soil, Ferric Chloride.
1. INTRODUCTION
Expansive soil is one among the problematic soils that has a high potential for shrinking or swelling due to
change of moisture content. Expansive soils can be found on almost all the continents on the Earth.
Destructive results caused by these soils have been reported in many countries. In India, large tracts are
covered by expansive soils known as black cotton soils. The major area of their occurrence is the south
Vindhyachal range covering almost the entire Deccan Plateau. These soils cover an area of about 200,000
square miles and thus form about 20% of the total area of India. To a large extent they are found in regions
having low to medium slope and poor drainage conditions. The primary bed rock is basalt or trap and in some
locations quartizites, schists and sedimentary rocks are found. It is expensive in nature due to the presence of
montmorillonite and illite clay minerals. Some of these black cotton soils are also found to contain high
amount of carbonates. The depth of black cotton soils can be as high as 20m.
The primary problem that arises with regard to expansive soils is that deformations are significantly greater
than the elastic deformations and they cannot be predicted by the classical elastic or plastic theory. Movement
is usually in an uneven pattern and of such a magnitude to cause extensive damage to the structures resting on
them.
Proper remedial measures are to be adopted to modify the soil or to reduce its detrimental effects if expansive
soils are indentified in a project. The remedial measures can be different for planning and designing stages
and post construction stages. Many stabilization techniques are in practice for improving the expansive soils
in which the characteristics of the soils are altered or the problematic soils are removed and replaced which
can be used alone or in conjunction with specific design alternatives. Additives such as lime, cement, calcium
chloride, rice husk, fly ahs etc. are also used to alter the characteristics of the expansive soils. The effect of the
additives and the optimum amount of additives to be used are dependent mainly on the mineralogical
481 Mallika, B. Ganesh
International Journal of Engineering Technology Science and Research
IJETSR
www.ijetsr.com
ISSN 2394 – 3386
Volume 4, Issue 10
October 2017
composition of the soils. The project focuses about the various stabilization techniques that are in practice for
improving the expansive soil for reducing its swelling potential and the limitations of the method of
stabilization there on. Modification of BC soil by chemical admixture is a common method for stabilizing the
swell-shrink tendency of expansive soil.
2. LITERATURE REVIEW
Expansive soils pose the greatest hazards that many geotechnical engineers face. Such soils may cause heavy
damages in light loaded structures such as water canals, reservoirs, highways, railways and airport runways
etc., unless appropriate measures are taken. Various stabilization techniques are in practice for improving
expansive soils by reducing its swelling potential and increasing its strength characteristics. Modification of
expansive soil by chemical admixture is a common practice for stabilizing the swell shrink tendency of
expansive soil, Advantages of chemical stabilization are that they reduce the swell-shrink tendency of
expansive soils and also render the soils less plastic.
In this section, the experiences of various investigators concerning chemical stabilization using
calcium chloride have been reviewed. Numerous investigators have studied the influence of lime, cement,
lime-cement, lime-fly ash, and cement–fly ash mixes on soil properties, mostly focusing on the strength and
swelling aspects. Among the chemical stabilization methods for expansive soils, lime stabilization is mostly
adopted for improving the swell-shrink characteristics of expansive soils. As lime and cement are binding
materials, the strength of soil-additive mixtures increases provided the soil is reactive with them. However, for
large-scale field use, the problems of soil pulverization and mixing of additives with soil have been reported
by several investigators.
Calcium chloride is an inorganic salt, which is a by-product of sodium carbonates. The use of
calcium chloride in place of lime, as calcium chloride is more easily made into calcium charged supernatant
than lime. Recent study indicated that CaCl2 could be an effective alternative to conventional lime used due to
its ready dissolvability in water and to supply adequate calcium ions for exchange reactions.
Petry and Armstrong (1989) stated that the calcium ions are the most effective and abundantly available in
calcareous fly ash, lime and calcium chloride, further the authors mentioned that the reasons why calcium
chloride has not been widely used are not clear. It is believed that the main one is economics, but perhaps it is
also because little definitive research has been done to define or support its use. Calcium chloride is known to
be more easily made into calcium charged supernatant than lime an helps in ready cation exchange reactions.
(Ramana Murthy, 1998). Mitchell and Radd (1973) also felt that CaCl2 might be effective in soils with
expanding lattice clays. Though, it is claimed that the magnitude of leaching in highly expansive clays
(KuulaVaisanen et al, 1995) over cycles of wetting and drying could be controlled by using Na2SiO3 along
with CaCl2. Though several works have been reported covering various aspects of chemical stabilization of
expansive soils, the understanding on cyclic swell-shrink behavior of stabilized and unstabilized soils was not
clear.
Chen and Ma (1987) felt that shrinkage cannot be treated as an image reflection of swelling and over a great
portion of the world shrinkage problems pose more of a threat to structural damage than swelling problems
especially in expansive clays of illite mineralogy.
Driscoll (1983) reported that in Britain, problems associated with swelling clays are largely related to the
shrinkage caused by extraction of moisture through tree roots. It is more useful if the complete cyclic swelling
and shrinkage behavior is understood.
Abouleid (1985) observed that there is nearly no volume change for remoulded clay specimens after three or
four wetting and drying cycles. From this discussion, it is evident that one group of researchers felt that the
swelling ability of clay decrease after few cycles of drying and wetting and yet another group recorded
increase in volume change after cyclic wetting and drying.
Reddy et al (1981) reported that, the test tracks with Murom sub-base and lime-pozzalana sub-base are rated
as the best among the ten test tracks constructed on expansive soil sub-grade with different sub-base courses.
482 Mallika, B. Ganesh
International Journal of Engineering Technology Science and Research
IJETSR
www.ijetsr.com
ISSN 2394 – 3386
Volume 4, Issue 10
October 2017
Deshpande et al (1990) concluded that lime stabilized sub base has shown better performance compared to
untreated section in the test track laid on expansive soil subgrade. Many researchers attempted to stabilize the
expansive soils by using different electrolytes. Here we discuss some of the projects carried out on expansive
soils using different electrolytes all around the world.
P. Venkata Muthyalu, K. Ramu and G.V.R. Prasada Raju (JNTUK) studied the “The Performance of
Chemically Stabilized Expansive Soil.”In this project they stabilized the expansive soil using electrolytes like
Potassium Chloride (KCL), Calcium Chloride (CaCl2) and Ferric Chloride (FeCl3). Ahmed T. M. Farid and
Mohamed I. Wahdan (Saudi Arabia) studied the “Behavior of Expansive Soil Treated by using Different
Electrolyte Substances.” In this project they stabilized the expansive soil by using electrolytes like Potassium