Claims:I CLAIM:
1. A process for stabilizing expansive soil, the process comprising:
characterizing the soil;
mixing the characterized soil with 0.1% - 2% calcium chloride (CaCl2); and mixing 1-15% of a mixture of Silicon dioxide (SiO2), Aluminium oxide (Al2O3), Ferric oxide (Fe2O3), Calcium oxide (CaO), Sulphur tri oxide (SO3), and Magnesium oxide (MgO).

2. The process as claimed in claim 1, wherein the soil is black cotton (BC) soil.

3. The process as claimed in claim 1, wherein CaCl2 is used in the range of 0.25% - 1%.

4. The process as claimed in claim 1, wherein the mixture of SiO2, Al2O3, Fe2O3, CaO, SO3, and MgO is used in the range of 2.5% to 10%.

5. The stabilized expansive soil as derived from the process as claimed in claim 1, wherein the composition in terms of atomic weight of the constituents is 14.6-20.9% of carbon (C), 45.97-48.7% of oxygen (O), 1.37-1.48% of magnesium (Mg), 8.21%-9.04% of aluminium (Al), 17.45-19.28% silicon (Si), and 6.1-6.9% of calcium (Ca).

6. The stabilized expansive soil as claimed in claim 5, wherein the specific gravity ranges from 2.71-2.85, sand 10.15-14.15%, clay 50.57-54.76%, natural water content 31-43%, liquid limit is 47-62.15%, plastic limit 21.53-34.5%, plasticity index 13-46.27%, shrinkage limit 10.38-25.6%, maximum dry density 15.1-15.88%, optimum moisture content 20.05-25.7%, swell potential 0.34-24.99 and swell pressure 15-204.

7. The stabilized expansive soil as claimed in claim 5, wherein free swell index is 0-77.27%, free swell ratio is 1-1.77, activity 0.25-0.72, water absorption 42.77 – 61.69%, sensitivity 1.16-3.53, void ratio 0.7-0.85, porosity 0.41-0.46, cation exchange capacity 43.63-79.82 meq/ 100g, cation exchange capacity activity 0.85-1.468, specific surface area 50.6-77.6 m2/g and specific area activity 0.98-1.44.
, Description:FORM 2
THE PATENTS ACT 1970
39 of 1970
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See sections 10 & rule 13)
1. TITLE OF THE INVENTION

COHESIVE HARD SOIL AS SUPPLEMENT BENEATH LIGHT AND HEAVY WEIGHT STRUCTURES FOR HIGH SWELLING SOILS
2. APPLICANTS (S)
(a) NAME (b) NATIONALITY (c) ADDRESS

R. SURESH
INDIAN
H.NO: 30-225/A/3/2 DWARAKAMAY COLONY, VINAYAK NAGAR, OLD
SAFILGUDA, SECUNDERABAD, PIN CODE: 500056, TELANAGANA, INDIA.

3. PREAMBLE TO THE DESCRIPTION

COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION:
[0001] The present invention relates to a facile method of reducing the swelling properties and improves the shear strength of the expansive soil through chemical action.

BACKGROUND OF THE INVENTION
[0002] Expansive soil deposits occur in the arid and semi-arid regions in the world. They cover a major portion on the geographical area in the world and about one fifth the area of India (approximately 3,00,000 sq. km), such soils are popularly perceived as black cotton soils and found extensively in Andhra Pradesh, Gujarat, Karnataka, Madhya Pradesh, Maharashtra and Tamil Nadu.
[0003] These soils are problematic to engineering structures because of their tendency to heave during wet season and shrink during dry season. They lie in top about 4.0-meter depth in most places and exhibit swell-shrink behavior owing to fluctuating water content. To deals with the problems of soils in deposits underlying the light weight structures characterized by swelling potential and swelling pressure, it was considered necessary to secure field strength parameters and to obtained soil sample to evaluate various Engineering, physical, chemical, mineralogical microstructural and morphological properties in the laboratory.
[0004] Many techniques and methods have been developed to improve engineering properties of such soils. These include soil stabilization using cement, lime, CNS layers and other admixtures like GGBS etc. The cohesive non-swelling soil [CNS] layers technology developed by R.K. KATTI 1967. The use of [CNS] cushions below the lightweight structures is well accepted, especially when the structures cover large area such as flooring, pavements, and canal lining. CNS layer is effective in counteracting the swelling potential and swelling pressure characteristic of underlying expansive soils but it was found that due to the punching shear failure that takes place in the CNS materials and its bearing capacity is much less compared to underlying black cotton soil under saturated and no swelling condition.
[0005] In this invention based on experimental results it is superior than CNS layers, alternative cohesive material is proposed to be prepared using the native black cotton soil by admixing with it alccofine-1203 and CaCl2 by dry weight of soil designating the mix as Cohesive Hard Soil [CHS] cushions. The maneuver of [CHS] cushion is found to be superior to conventional CNS cushion, which could be attributed to its non-swelling and high shear strength appeared as a [CHS] cushion interface stabilization in the presence of alccofine-1203 and CaCl2.
[0006] Expansive soils are known worldwide for their volume change behaviour due to moisture fluctuation because of their intrinsic mineralogical behaviour [Ramana murty, V., Hari Krishna, P., 2006]. These types of soils are found mainly in the arid and semi-arid region [Mishra, A.K., Dhawan, S., Rao, S.M., 2008] in the world, such as Australia, Canada, China, India, South Africa, and the United states. In India has extensive track of expansive soils known as black cotton soil covers about twenty percentage of the total land area [Ramana murty, V., Praveen, G.V., 2007]. Due to its black colour which is a result of high iron and magnesium minerals acquire from basalt [Lal, R., 2007].
[0007] Expansive soils are clayey soils are extensive specific surface area and high cation exchange capacity [Nalbantoglu, Z., 2004, Nalbantoglu, Z., Gucbilmes, E., 2001]. Expansive soil contains clayey minerals such as montmorillonite, which increases in volume during wetting. They exhibit low shear strength as well as high swell and shrink characteristics. Clay soils are found on everywhere in the continuant on the Earth. In the under-developed nations, much of the expansive soil problems may not have been recognized. It is to be expected that more expansive soil problems may not have be recognized. It is to be expected that more expansive soil regions will be discovered each year as the amount of construction increases.
[0008] This type of soil has been always presented problems for pavements, sidewalk, driveways, basement floors, pipelines, light loaded structures, by merging under load and by changing volumetrically alongside regular dampness variety. Pernicious results caused by this type of soils have been reported in many countries.
[0009] The expansive soil areas are generally stiff and it will affect the change of lightly loaded structural cracking due to settlements is rather remote. At the same time, there are a large number of instances where heave cracks have appeared in the basement walls that were not caused by foundation heaving, but the earth pressure exerted on the walls, generally compounded by seepage pressure. In most cases where vertical or horizontal cracks developed in the basement wall, earth pressure problems are suspects.
[00010] Diagonal cracks that develop below windows and above doors are a strong indication of swelling movement. Since the expansive soils are found worldwide, the challenges to the civil engineers in one felt around the globe. If not adequately treated, expansive soils may act as a natural hazard resulting in several damages to structures [Al Rawas, A.A., 2002, Al Rawas, A.A., Taha, R., Nelson, J.D., Al-shab, T.B., Al-siyabi, H., 2002].
[00011] The annual cost of damages to the civil engineering structures is estimated as 150 million in the U.S and many billions of dollars worldwide [Gourly, C. S., Newill, D., and Schreiner, H.J. 1993]. Under the moisture ingress and digress, a building founded on expansive soil undergo differential movements caused by alternate swell/shrink behaviour of soil causing several structural damages.
[00012] Many reported data are available on the heave profile of soil at the surface, at various depths from the ground surface, and on covered areas [Puppala, A., J., et.al. 2005, Mishra, A.K., Dhawan, S., Rao, S.M., 2008, Rao, K.S., et.al. 1994] it is generally observed that the amplitude of soil movement decreases with depth and there is an increase in time lag with movement at depth compared with that at the surface. To date, distress problems related to this type of soils is quite immense have ensue in the loss of billions of dollars in repairs and rehabilitation [Nelson, J.D., Miller. D., J., 1992]. The clay minerals are basically hydrated aluminium silicates in a crystalline form. The electrical forces acting on the surface of the smaller size particles are much greater than the gravitational forces. Absorption of water by clays leads to expansion, the mineralogical standpoint, a magnitude of expansion depends upon the kind and amount of clay minerals present, their exchangeable ions, electrolyte content of aqueous phase and the internal structure.
[00013] In the soil classification system, clays are defined as the particles of size less than 2 micron. Particle size alone does not determine clay mineral. The type of the clay mineral plays a dominant role in controlling the physical and engineering properties of fine-grained soils (Peck,R., Hanson,W. and Thornburn,T., 1974). For smaller size particles, the electrical forces acting on the surface of the particles are much greater than the gravitational force. These soil particles are said to be in the colloidal state.
[00014] The colloidal particles consist primarily of clay minerals that were derived from parent rock by weathering. Three most important groups of clay minerals are montmorillonite, illite and kaolinite which are crystalline hydrous aluminosilicates. Montmorillonite is the clay mineral that presents most of the expansive soil. Absorption of water by clays leads to expansion. From the mineralogical standpoint, the magnitude of expansion depends up on the kind and amount of clay minerals present, there exchangeable ions, electrolyte content of aqueous phase, and the internal structure. Clay mineral has the property of sorbing certain anions and cations and retaining them in an exchangeable state.
[00015] The exchangeable ions are held around the outside of the silica alumina clay mineral structural unit, and the exchange reaction does not affect the structure of the silica-alumina pocket. In clay minerals, most common exchangeable cations are C++, Mg++, H+, K+, NH4+, Na+, frequently in about that order of general relative abundance. The existences of such charges are indicted by the ability of clay to absorb ion from the solution. Cations (positive ions) are more readily absorbed than anions (negative ions).
[00016] A cation such as Na+ is readily attracted from a salt solution and attracts to a clay surface. However, the adsorbed Na+ ion are not permanently attached; it can be replaced by K+ ions if the clay is placed in a solution of potassium chloride (KCL). The process of replacement by excess cation is called cation exchange by Grim, R.E., 1968. Cation exchange phenomenon takes place in everyday life. The basic principal involved in the chemical stabilization of expansive soil is the increases in the ion concentration in the free water and Base Exchange phenomenon.
[00017] Various innovative techniques such as special foundations that include belled piers, drilled piers, Granular pile-anchor (GPA), friction piles and moisture barriers have been developed to mitigate the problem posed by the expansive soils. Apart from this techniques, stabilization of expansive soils with various additive including fly ash, lime, cement, calcium chloride, have also met with considerable success [Desai I .D. and Oza B. N. 1977, Phani kumar, B., R., Sana Suri, 2013, Satyanarayana, B 1966].
[00018] Stabilization of expansive soils with admixture controls the potential of soils for a change in volume. Lime and cement are well known additive to improve pozzolanic reactivity and for the stabilization of expansive soils are associated with the emission of greenhouse gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O). Physic-chemical mechanism of the lime treatment of soil are well established [Mitchell, J., 1993], four mechanisms [cation exchange, flocculation, carbonation, pozzolanic reactions] are generally associated with the modification and stabilization of lime treated soils.
[00019] Further, there has been an increased in the awareness of environmental and ecosystem degradation due to huge production and storage of waste materials is also initiated to stabilize problematic soil, alone or in combination with lime, effectively and economically [Maher, et. al. 1993, Smith, R. L., 1993, Jalali, S et.al.1997, Consoli, et.al. 1998, Kalidas, N., Bhanumathidas,N., 2005, Higgins, D.D., 2005, Muntohar, A.S., 2009, Pal, S.K., Ghosh, A., 2013].
[00020] It has been felt by researchers that strong electrolytes such as potassium chloride, magnesium chloride, zinc chloride, sodium hydroxide, ferric chloride and calcium chloride could be tried instead of lime [Desai I .D. and Oza B. N. 1977, Frydman S., et.al., 1977, Yousry M. and Mowafy M. 1985, Rao S. M. and Subba Rao K. S. 1994, Chandra Sekhar B. P., et.al. 2001] strong electrolytes are readily soluble in water and hence could supply adequate cations for exchange reactions. Industrial by-product material such as flyash [Cokca, E., 2001, Ferguson, G., 1993, Phani kumar, B., Sharma, R.S., 2004], GGBS [Cokca, E., et.al. 2009, Higging, D., 2005], cement kiln dust [Miller, G. A., Azad, S., 2000, Zaman, M., Laguros, J., A., 1992], limestone dust [Brooks, R., et.al. 2010] as additive are becoming more popular due to their relatively low cost additionally CO2, emission can be reduced significantly by the increased use of such supplementary cementing materials currently wasted in lagoons and landfill sites.
[00021] The most important feature in the stabilization of clay soils is the ability to stabilizer to provide enough calcium [Wang, L., 2002]. Industrial waste such as fly ash and blast furnace slag can be used as stabilizing agent because they are siliceous and calcareous materials. Granular pile- anchor (GPA) technique has been a recent innovation over the conventional granular pile, modified into anchors by Phani kumar, et.al. 2018.
[00022] Stabilization of expansive soil with admixtures controls the potential of soils for a change in volume. In recent years a number a stabilizer from various industries have been developed for the purpose of soil stabilization. Stabilizers can be amended with activators like lime or cement to enhance their cementitious and pozzolanic properties. The technique of cohesive non-swelling (CNS) soil layers have most popular and the concept has successfully been applied to reduce swell and swelling pressure in black cotton soils. In the last 40 years, thousands of swell tests were conducted by the authors on various kinds of expansive soils.
[00023] When CNS soil is put as a cushion between the foundation and the ground or between the canal lining and the ground, it absorbs most of the movements of the ground, thus subjecting the foundations or the canal linings only to small and acceptable movements. More the cushion thickness more will be the effectiveness. Cushion thickness ratio is defined as the ratio of CNS soil cushion to the thickness of active zone. Active zone is the depth of expansive soil which produces volume changes as a consequence of changes in moisture content. Prof. Katti (1979) developed the specifications for CNS soil and the same have been accepted by the Bureau of Indian Standards (IS 9451; 1994).
[00024] Among other things, the constituents of the soil are required to be within certain ranges to make the soil CNS. The standard procedure used to conduct these tests is to place the undisturbed sample in a consolidometer under a surcharge load of 0.05 kg/cm2 for 24 hours. Saturate the sample, measure and record the amount of volume change.
[00025] After the sample had swelled to its maximum extent, the specimen was loaded until it returned to its initial volume and the required to do this was designated as a swelling pressure by F.H. chen-1983. R.K.Katti, Moza and D.R. Katti proposed the following expressions to evaluate the thickness of the CNS layer is effective in counteracting the swelling potential and swelling pressure characteristic of underlying expansive soils but it was found that due to the punching shear failure that takes place in CNS materials, its bearing capacity is much less compared to underlying black cotton soil under saturated and no swelling condition.
[00026] To improve the bearing capacity of CNS materials, it was also proposed that a layer of mechanically stabilised mix (MSM) be over laid on the CNS materials by R.K.Katti - 1983. Ramana Murty, V., [2008] studied on the modification of black cotton soil using CaCl2 and rice-husk-ash (RHA), which resulted in combinations of soil + 1% CaCl2 + 6% RHA with non-swelling properties, while retaining up to 350kPa unconfined compressive strength value for 28 days of curing period.
[00027] Although there are several techniques known in the art of expansive soil stabilization, they are prone to problems as discussed above. Therefore, there is a still need and scope for improving expansive soil with no swelling and high shear strength cushion techniques.

OBJECTS OF THE INVENTION
[00028] It is an object of the present invention to provide a provide stabilization of expansive soils.
[00029] It is an object of the present invention to provide a device a process for the stabilization of the expansive soil.
[00030] It is an object of the present invention to provide a system and method for an improved Soil testing system.
[00031] It is an object of the present invention to provide an avenue for improving expansive soil with no swelling.
[00032] It is an object of the present invention to provide a system and method for an improved sensor device system.

SUMMARY OF THE INVENTION
[00033] In one embodiment, the present invention discloses and claims a process for stabilizing expansive soil, included but not limited to black cotton (BC) soil, the process comprising characterizing the soil; mixing the characterized soil with 0.1% - 2%, preferably in the range of 0.25% - 1% of calcium chloride (CaCl2); and mixing 1-15%, preferably 2.5-10% of a mixture of Silicon dioxide (SiO2), Aluminium oxide (Al2O3), Ferric oxide (Fe2O3), Calcium oxide (CaO), Sulphur tri oxide (SO3), and Magnesium oxide (MgO).
[00034] In practical embodiment of the invention, the stabilized expansive soil is disclosed as derived from the process wherein the composition in terms of atomic weight of the constituents is 14.6-20.9% of carbon (C), 45.97-48.7% of oxygen (O), 1.37-1.48% of magnesium (Mg), 8.21%-9.04% of aluminium (Al), 17.45-19.28% of silicon (Si), and 6.1-6.9% of calcium (Ca).
[00035] The properties of stabilized expansive soil of specific gravity ranges from 2.71-2.85, sand 10.15-14.15%, clay 50.57-54.76%, natural water content 31-43%, liquid limit is 47-62.15%, plastic limit 21.53-34.5%, plasticity index 13-46.27, shrinkage limit 10.38-25.6%, maximum dry density 15.1-15.88 kN/m3, optimum moisture content 20.05-25.7%, swell potential 0-24.99% and swell pressure 0-204 kPa.
[00036] The free swell index of the stabilized expansive soil is 0-77.27%, free swell ratio is 1-1.77, activity 0.25-0.72, water absorption 42.77 – 61.69%, sensitivity 1.16-3.53, void ratio 0.7-0.85, porosity 41 – 46%, cation exchange capacity 43.63-79.82 meq/ 100g, cation exchange capacity activity 0.85-1.468, specific surface area 50.6-77.6 m2/g and specific area activity 0.98-1.44.
[00037] To endorse its suitability to be used as construction materials as a cushion layer below the light loaded building structures, vehicle parking sheds, sidewalks, floorings, canal lining and light and heavier loaded pavements. The physical, chemical, mineralogical, microstructural and morphological properties of the expansive soil were studied by performing Engineering properties, atterberg’s limits, specific gravity, hydrometer analysis, free swell index, optimum moisture content, maximum dry density, unconfined compressive strength, consolidation, cation exchange capacity (CEC), specific surface area (SSA), SEM with EDX and XRD analysis. Based on the results, it can be concluded that the expansive soil with 7.5% of alccofine-1203 and 1% of CaCl2 can be considered as an effective cohesive hard soil (CHS) cushions layer for various Civil Engineering constructions.

BRIEF DESCRIPTION OF THE DRAWINGS
[00038] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:
Figure 1: X-ray diffraction patterns of the soil stabilization
a) Natural soil – 0-day, b) Soil + 5% Alccofine-1203 0-day, c) Soil + 1% CaCl2 + 7.5% Alccofine-1203 28-day, d) Soil + 1% CaCl2 + 10% Alccofine-1203 28 –day [CH=Calcium hydroxide; Q=Quartz; CSH=Calcium Silicate Hydrate; CC=Calcite; CR= Cristobalite]

Figure 2: SEM and EDAX Analysis of:
a) and b) Soil; and c) and d) Soil + 5% Alccofine-1203, 0-day,
Figure 2A: SEM and EDAX Analysis of:
e) and f) Soil + 1% CaCl2 + 7.5% Alccofine-1203 28-day; and g) and h) Soil + 1% CaCl2 + 10% Alccofine-1203 28 – day
Although specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.

DETAILED DESCRIPTION
[00039] At the very outset of the detailed description, it may be understood that the ensuing description only illustrates a form of this invention. However, such a form is only exemplary embodiment, and without intending to imply any limitation on the scope of this invention. Accordingly, the description is to be understood as an exemplary embodiment and teaching of invention and not intended to be taken restrictively.
[00040] Throughout the description and claims of this specification, the phrases “comprise” and “contain” and variations of them mean “including but not limited to”, and are not intended to exclude other moieties, additives, components, integers or steps. Thus, the singular encompasses the plural unless the context otherwise requires. Wherever there is an indefinite article used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
[00041] Thus, the terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a device, system, assembly that comprises a list of components does not include- only those components but may include other components not expressly listed or inherent to such system, or assembly, or device.
[00042] In other words, one or more elements in a system or device proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system, apparatus or device.
[00043] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with an aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.
[00044] All the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification including any accompanying claims, abstract and drawings or any parts thereof, or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
[00045] The reader's attention is directed to all papers and documents which are filed concurrently with or before this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. Post filing patents, original peer reviewed research paper shall be published.
[00046] The following descriptions of embodiments and examples are offered by way of illustration and not by way of limitation. Unless contraindicated or noted otherwise, throughout this specification, the terms “a” and “an” mean one or more, and the term “or” means and/or. As used in the description herein and throughout the claims that follow, the meaning of “a.” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[00047] The swelling of expansive soil depends on various factors such as the degree of saturation, dry density, type of clay mineral equilibrium moisture content etc. The invention was carried a cohesive Hard Soil (CHS) cushion layers for stabilization of expansive soils. The maneuver of [CHS] cushions which could be attributed to its no swelling and high shear strength of soil. CHS material helps to bring about a higher rate of cohesive bond formation around the particles at a faster rate than that of ingress of the water molecules in the interlayer of expanding montmorillonite clay mineral lattice present in black cotton soil.
[00048] The CHS layer is to be quite helpful in increasing the bearing capacity of the whole system. The consolidation characteristics are as described for CHS is no volume change. So, when a CHS layer comes in to contact with black cotton soil prior to saturation, it develops an electrical environment at the interface and below. The environment and the weight of the CHS together help in developing absorbed water bonds during saturation in soil system. CNS (cohesive non- swelling) soil layers appear that the shear strength is bilinear compared to intrinsic soil by R.K.Katti. The maneuver of [CHS] cushion is found to be superior to conventional CNS cushion, which could be attributed to its no swelling and high shear strength appeared in [CHS] cushion interface stabilization in the presence of Alccofine-1203 and CaCl2.
[00049] The purpose of this study is to investigate the influence of inclusion of alccofine in conjunction with Calcium chloride (CaCl2) in the stabilization of expansive soils. In India, an industrial product alccofine material is manufactured by ambuja cement private limited. The majority of alccofine material is utilized in the high-performance concrete structures either as a cement replacement or as an additive to improve concrete properties in both fresh and hardened states and soil stabilization purpose [Rajesh Prasad shukla, et.al. 2015, Ramana murty, V., Praveen, G.V., 2007], while CaCl2 is mainly used to reduce the swelling and increase the shear strength of expansive soil for soil stabilization.
[00050] These alccofine and CaCl2 have also great potential to be used as stabilizing agents. The main reason for their underutilization is the lack of pozzolanic reactivity [Akshay Nadiger and Madhavan, K. 2019]. Alccofine is ultrafine ground granulated blast furnace slag (UFGGBS), performs a superior than all other mineral admixtures used in India. It is a fine material of particles size (Range 0-17microns) much finer than other hydraulic materials like cement, lime, fly ash [Akshay Nadiger and Madhavan, K. 2019].
[00051] Hence chemical activators such as lime or cement are added to improve its pozzolanic reactivity. On the other hand, CaCl2 is the hygroscopic material and hence is pre-eminently suited for stabilization of expansive soils, because it absorbs water from the atmosphere and prevents shrinkage cracks occurring in expansive soils during summer season [Mishra, A.K., Dhawan, S., Rao, S.M., 2008]. There is a variation in the chemical properties of Alccofine-1203 and CaCl2. Alccofine is having 33.6% calcium oxide and 35.6% silica content while CaCl2 is relatively high in calcium oxide.
[00052] The combination of the two materials can be more beneficial when used as a stabilizing agent then using them individual. However, no studies on the joint activation of alccofine-1203 and CaCl2 as stabilizing agents for expansive soils have been published to date.
[00053] The use of cohesive non-swelling soil (CNS) cushions below the lightweight structures is well accepted, especially when the structure covers a large area such as canal lining, floorings and pavements. CNS cushions is effective in counteracting the swelling and swelling pressure characteristic of underlying expansive soils but it was found that due to the punching shear failure that takes place in CNS materials, its bearing capacity is much less compared to underlying black cotton soil under saturated and non-swelling condition.
[00054] To improve the strength of intrinsic soil under saturated and no swelling condition, this investigation proposed that the Cohesive Hard Soil (CHS) cushions be over laid on the expansive soil under saturated and no swelling condition. In view of severe scarcity for suitable CNS materials at several project sites, an alternative cushion material is proposed to be prepared at the site using intrinsic black cotton soil (expansive soil) by admixing with it 7.5% Alccofine-1203 and 1% CaCl2 by dry weight of soil designating as the mix as cohesive hard soil (CHS).
[00055] The studies were also focused to bring out the relative performance of the proposed CHS cushion and the conventional CNS cushion based on the laboratory investigation. The performances of CHS cushion is found to be superior to conventional CNS cushions which could be attributed to its higher unconfined shear strength value while being non-swelling and possible clay-CHS cushion interface stabilization in presence of alccofine-1203 and CaCl2. The CHS cushion is carry appear a higher load is found; it is to be quite helpful in increasing the bearing capacity of soil. Based on the favorable results obtained, it can be concluded that the expansive soil with alccofine-1203 and CaCl2 can be considered as an effective cohesive hard soils (CHS) cushions for light load structures, sidewalks, floorings, canal lining, light load and heavier loaded pavements.
[00056] An attempt has been made in this study to utilize mixture of alccofine-1203 and CaCl2 as binder to stabilize expansive soil. The influence of the binder on index properties, swelling potential, swell pressure, FSI, compaction, unconfined compressive strength, SEM, XRD, Cation exchange capacity (CEC), specific surface area (SSA) characteristics of expansive soil have been considered for evaluating performance
[00057] EXPANSIVE SOIL: The expansive clay soil is collected from nasal in Villupuram district is in Tamil Nadu, India. The soil is collected in a dry condition at a depth of 1 meter below the ground level and preserved in the laboratory. Identified the index and engineering properties of expansive soils as shown in Table 1.
[00058] ALCCOFINE: Alccofine is ultrafine ground granulated blast furnace slag (UFGGBS), performs a superior than all other mineral admixtures used in India. It is a micro fine material of particles size much finer than other hydraulic materials like cement, lime, fly ash etc. manufactured by Ambuja cement private limited in India. Alccofine-1203 and Alccofine- 1101 are two types with low calcium silicate and high calcium silicate respectively. Alccofine-1203 has the average particle size 4 microns (Range 0-17microns). Alccofine has almost same binding characteristics as silica fume. It controls high reactivity because of controlled granulation and it also improves workability by reducing the water demand. Chemical composition and physical properties are tested by alccofine micro materials, pissurlem, Goa, India. Alccofine-1203 properties are given in table 2.
[00059] CALCIUM CHLORIDE: The chemical formula of calcium chloride is CaCl2. It is a hygroscopic material it also absorbs water from the air and releases heat when it is dissolved in water.
Table 1. Properties of Expansive soil:

Properties of soil Results
Sand (%) 14.86
Silt (%) 29.79
Clay (%) 55.35
Specific gravity 2.68
Liquid limit (WL) 70%
Plastic limit (WP) 18%
Shrinkage limit (WS) 8.34%
Free swell index (FSI) 81.82%
Water absorption (WA) 63.70%
Cation exchange capacity (CEC) meq/100g 83.65
Specific Surface area (m2/g) 92
Unified soil classification (USCS) CH
OMC (%) 22.95
MDD (kN/m3) 15.39
UCS (kPa) 103.96
Swell potential (%) 33.22
Swell pressure (kPa) 230

Table 2. Physical and chemical properties of Alccofine-1203

Physical properties
Particle size Distribution
D10 1.5
D50 4.3
D90 9.0
Specific gravity (g/cc) 2.88
Bulk density (kg/m3) 680
Chemical properties
SiO2 35.6%
Al2O3 21.4%
Fe2O3 1.3%
CaO 33.6%
SO3 0.12%
MgO 7.98%

[00060] Different tests can be used to characterize the Physical, Index, Engineering, Microstructural properties of stabilized soils. Some of the basic and important properties embrace plasticity, compaction, consolidation, and unconfined compressive strength. These properties lead to a routine laboratory soil testing procedure for stabilized soils and are related to other engineering properties including strength and stiffness. The present study focuses on evaluating the physical, chemical, mineralogical and microstructural behavior of soils in the laboratory. Experimental investigations have been carried out on expansive soil with the addition of varying percentages of alccofine-1203 (1-15 %) and calcium chloride of (0.1-2.0 %). The materials used in the investigation consist of 20 soils having different swelling behavior.
[00061] The physical properties of the above soils are determined by conducting the following tests as per IS codes. The specific gravity of clay soil sample was determined according to the Indian Standards, IS: 2720 (part 3) (1980). The grain size analysis of the soil was determined in accordance with IS: 2720(Part-4) (1985). Atterberg’s limit determined according to Indian Standard methods. The liquid limit of the soil was determined by the cone penetration method and the plastic limit by the conventional procedure described in IS: 2720(Part-5) (1985). The shrinkage limit of the soil sample was determined according to IS: 2720(Part-6) (1972). To determine the compaction characteristics of the soil mixed with both Alccofine-1203 and CaCl2 were added independently and blended to the expansive soil was carried out. Compaction test were conducted to determine optimum moisture content (OMC) and maximum dry density (MDD) as per IS: 2720 (Part 15)-1980. Unconfined compressive strength (UCS) testing have been carried out on the soil mixed with both Alccofine and CaCl2 were added independently and blended to the expansive soil in accordance with IS:4332(Part-5) (1970).
[00062] The UCS specimen size was 38mm in diameter and 76mm in length. The specimen was prepared by soil-admixtures blended with a respective optimum condition. A wet mix sample was then fed into a cylindrical mould and statically compacted. After extruding the sample, tests were conducted. The soils are classified as per (IS: 1498-1970). S1 to S18 samples are fall in CH (Unified soil classification system)and S19, S20 samples fall in CI (Unified soil classification system) therefore S1-S18 samples have clay percentage is more and high plasticity and S19 and S20 samples have clay percentage is less and low plasticity.
[00063] The swelling pressure is also depended on the method of testing. Two methods namely constant volume method and consolidometer are suggested in IS 2720 (Part 15) - 1977. Both the methods are consolidometer tests. Further, the field swelling pressure may significantly be different than that obtained from laboratory test IS 2720-1977 (Part-15). The soil amended with varying percentage of alccofine-1203 and CaCl2 carried out as per respected IS coda IS: 2720 (Part 15) -1977. The sample specimen compacted in 60 mm in diameter and 20 mm in height consolidated ring consistent with optimum moisture content (OMC) and maximum dry density.
[00064] Estimation of Swelling and Swelling Pressure of Soil: Empirical models for estimating swelling and swelling pressure of soils are developed by many researches. They are compiled and presented in Table 3.
Table 3 Empirical models for estimating swelling and swelling pressure of soils (after Erzin and Gunes 2013)

Relationships References
S = 2.16x103PI2.44 Seed et.al. (1962)
S = 60K(PI)2.44 F.H. Chen (1975)
Log Sp = -2.132 + 0.0208LL + 0.000565?d - 0.0269w Komomik and David (1969)
S = 2.29 x 10-2 PI1.45 (C/w) + 6.38 Nayak and Christensen (1971)
Log S = 0.0562 ?d+0.033LL -6.8 Vijayvergia and Sulvian (1973)
Log S = (1/19.5) (6.242 ?d+0.65LL -130.5) Vijayvergia and Ghazzaly (1973)
Log Sp = 0.9 (PI/w) – 1.19 Schneider and Poor (1974)
S = 2.77 + 0.121LL – 0.27w O’Neil and Ghazzaly (1977)
Log S = 0.036LL – 0.0833w + 0.458 Johnson and Snethen (1978)
Sp = 0.0446LL – 1.572
Sp = 0.057LL – 0.0566 Nayak (1979)
S = 0.000195LL4.17 w2.33 Weston (1980)
S = 0.2558e0.0838 PI Chen (1988)
Log Sp = - 4.812 +0.01405PI + 2.394 ?d – 0.0163w
Log Sp = - 5.917 +0.01405PI + 2.408 ?d – 0.819LI
Log Sp = - 5.020 +0.01383PI + 2.356 ?d Erzin and Erol (2004)
Sp = 63.78e0.1528 S
Sp = 48.32S Sridharan and Gurtug (2004)
S = 1+0.06(C+ PI –w )
Sp = 135 +2(C+PI –w ) Sabtan (2005)
S=- 432.06 +7.73 C +0.12CEC +0.46PI +4.31 ?d– 1.18w
Sp=-1346.2+257.1C+43.13CEC-18.18PI+33.43?d–
25.21w – 3.41S Erzin and Gunes (2011)
Sp = 93.3 FS- 53.4 Kayabali and Demir (2011)
Sp= 1.9319S1.2897 Erzin and Gunes (2013)

[00065] Abbreviations: S= Swelling, Sp= Swelling Pressure, LL= Liquid Limit, PI= Plasticity Index, ?d= dry density of soil, w= water/moisture content, K= 3.6x 10-5 constant CEC=Cation Exchange Capacity, C= clay percent, LI = liquidity index, FS= Free Swell.
[00066] The water absorption (WA) of the soil mixed with both Alccofine and CaCl2 were added independently and blended to the expansive soil. A water absorption (WA) equation is developed and recommended by [Sridharan, A and Nagaraj, H., B., 2009]. Water absorption equation is
WA = 0.91WL
Where: WA = Water absorption, WL = liquid limit.
The degree of expansivity of a fine-grained soil can be known by a term Free Swell Index (FSI) defined by
FSI = ((Vd - Vk)/ Vk) x 100)
Where Vd is the equilibrium sediment volume of 10g of oven dry soil passing 425 µm sieves placed in a 100ml graduated measuring jar containing distilled water and Vk is the equilibrium sediment volume of 10g of oven dry soil passing 425 µm sieves placed in a 100ml graduated measuring jar containing kerosene.
[00067] However, this method gives negative free-swell indices for kaolinite-rich soils and may underestimate the expansivity of montmorillonite soils if the soils contain a significant amount of kaolinite clay materials. To overcome this difficulty, Sridharan and Prakash (2000) under another term, free Swell Ratio (FSR), which is the ratio of equilibrium sediment volume of 10g oven- dried soil passing through a 425-micron sieve in distilled water to that in carbon tetrachloride. Table 5 shows the classification of expansive soils based on various Index properties as per IS: 1498-1970 and based on free swell ratio of Sridharan and Prakash (2000).
FSR = Vd/Vk

Table 4 shows the classification of expansive soil based on Index properties:

LL (%)
PI (%) Frees well Index (%) Free Swell Ratio Swell Potential (%) Degree of Expansion Degree of Severity
20-35 <12 <50 1-1.5 1-5 Low Non-critical
35-50 12-23 50-100 1.5-2 5-15 Medium Marginal
50-70 23-32 100-200 2-4 15-25 High Critical
70-90 >32 >200 >4 >25 Very High Severe

[00068] To determine the Specific Surface Area (SSA) of the soil-binder mixtures, a Specific Surface Area is developed and recommended by (Amy cerato, 2002). The measurement of total surface area was conducted using the Ethylene Glycol Monoethyl Ether (EGME) method. Table.6. shows the SSA for different clay minerals. Calculate specific surface area (SSA) as
SSA = Wa/0.000286Ws
Where
SSA: Specific Surface area in m2/g; Wa = Weight of Ethylene Glycol Monoethyl Ether (EGME) retained by the sample in grams; Ws = Weight of soil added initially.
[00069] To determine the Activity of soil is developed by Skempton (1953). It is the ratio of plasticity index to clay fraction. The cation exchange capacity (CEC) of the soil soil-admixtures blended samples is determined. The Cation Exchange Capacity (CEC) is developed and recommended by (Mokeagus, J.A). Table.6. shows the different cation exchange capacity for different clay minerals. Sensitivity (St): It is defined as the ratio of the unconfined compressive strength of an undisturbed specimen of the soil to the unconfined compressive strength of a specimen of the same soil after remolding at unaltered eater content.
Table 5. Ranges of Cation Exchange Capacities and specific surface of various clay minerals: (After Woodward- Clyde and Associates 1967)

Description Kaolinite Illite Montmorillonite
Particle thickness 0.2-2 (microns) 0.003-0.1 (microns) Less than 9.5A
Particle diameter 0.5-4 (microns) 0.5- 10 (microns) 0.05-10 (microns)
Specific surface(m2/g) 10-20 65-180 50-840
Cation exchange capacity
(milliequivalents per 100g) 3-15 10-40 70-80

MINERALOGICAL AND MICROSTRUCTURAL ANALYSIS:

The analysis (SEM with EDAX and XRD) are carried out on sample collected from fractured portion of UCS specimens after completion of test. It has been carried out to elucidate the mechanism of strength variation through change in mineralogy and microstructure, respectively.
[00070] The present formulation is further clarified by giving the following exhibits. It must, however, be understood that these exhibits are only illustrative in nature and should not be taken as limitations to the capacity of the invention. Several amendments and improvements to the disclosed segments will be obvious to those skilled in the art. Thus, these amendments and improvements may be made without deviating from the scope of the invention.
Example 1:
SOIL TESTING METHODOLOGY
Different tests can be used to characterize the Physical, Index, Engineering, Microstructural properties of stabilized soils. Some of the basic and important properties embrace plasticity, compaction, consolidation, and unconfined compressive strength. These properties lead to a routine laboratory soil testing procedure for stabilized soils and are related to other engineering properties including strength and stiffness. The present study focuses on evaluating the physical, chemical, mineralogical and microstructural behavior of soils in the laboratory. Experimental investigations have been carried out on expansive soil with the addition of varying percentages of alccofine-1203 (2.5%, 5%, 7.5% and 10%) and calcium chloride (0.25%, 0.50% and 1.0%). The materials used in the investigation consist of 20 soils having different swelling behavior. One natural soil and nineteen prepared soils have been taken for experimentation as shown in table 6.
[00071] Physical properties of the soils are determined by conducting the following tests as per IS codes. The specific gravity of clay soil sample was determined according to the Indian Standards, IS: 2720 (part-3) (1980). The grain size analysis of the soil was determined in accordance with IS: 2720(Part-4) (1985). Atterberg’s limit determined according to Indian Standard methods. The liquid limit of the soil was determined by the cone penetration method and the plastic limit by the conventional procedure described in IS: 2720 (Part-5) (1985). The shrinkage limit of the soil sample was determined according to IS: 2720 (Part-6) (1972). To determine the compaction characteristics of the compaction characteristics of the soil mixed with both Alccofin-1203 and CaCl2 were added independently and blended to the expansive soil was carried out. Compaction test were conducted to determine optimum moisture content (OMC) and maximum dry density (MDD) as per IS: 2720 (Part 15)-1980. Unconfined compressive strength (UCS) testing has been carried out on the soil mixed with both Alccofine-1203 and CaCl2 were added independently and blended to the expansive soil in accordance with IS:4332(Part-5) (1970).
[00072] The UCS specimen size was 38mm in diameter and 76mm in length. The specimen was prepared by soil-admixtures blended with a respective optimum condition. A wet mix sample was then fed into a cylindrical mould and statically compacted. After extruding the sample, tests were conducted. The soils are classified as per (IS: 1498-1970). S1 to S18 samples are fall in CH (Unified soil classification system) and S19, S20 samples fall in CI (Unified soil classification system) therefore S1-S18 samples have clay percentage is more and high plasticity but S19 and S20 samples have clay percentage is less and low plasticity.
[00073] The swelling pressure is also depended on the method of testing. Two methods namely constant volume method and consolidometer are suggested in IS 2720 (Part 15) - 1977. Both the methods are consolidometer tests. Further, the field swelling pressure may significantly be different than that obtained from laboratory test IS 2720-1977
[00074] (Part-15). The soil amended with varying percentage of alccofine-1203 and CaCl2 carried out as per respected IS coda IS: 2720 (Part 15) -1977. The sample specimen compacted in 60 mm in diameter and 20 mm in height consolidated ring consistent with optimum moisture content (OMC) and maximum dry density.
Table 6. Expansive soils used in the present work

Si. No. Designation of soil Combinations Types of soil
1 S1 Black cotton (BC) soil Natural
2 S2 BC soil + 2.5% Alccofine-1203 Prepared
3 S3 BC soil + 5% Alccofine-1203 Prepared
4 S4 BC soil + 7.5% Alccofine-1203 Prepared
5 S5 BC soil + 10% Alccofine-1203 Prepared
6 S6 BC soil + 0.25% CaCl2 Prepared
7 S7 BC soil + 0.25% CaCl2+ 2.5% Alccofine-1203 Prepared
8 S8 BC soil + 0.25% CaCl2+ 5% Alccofine-1203 Prepared
9 S9 BC soil + 0.25% CaCl2+ 7.5% Alccofine-1203 Prepared
10 S10 BC soil + 0.25% CaCl2+ 10% Alccofine-1203 Prepared
11 S11 BC soil + 0.5% CaCl2 Prepared
12 S12 BC soil + 0.5% CaCl2+ 2.5% Alccofine-1203 Prepared
13 S13 BC soil + 0.5% CaCl2+ 5% Alccofine-1203 Prepared
14 S14 BC soil + 0.5% CaCl2+ 7.5% Alccofine-1203 Prepared
15 S15 BC soil + 0.5% CaCl2+ 10% Alccofine-1203 Prepared
16 S16 BC soil + 1.0% CaCl2 Prepared
17 S17 BC soil + 1.0% CaCl2+ 2.5% Alccofine-1203 Prepared
18 S18 BC soil + 1.0% CaCl2+ 5% Alccofine-1203 Prepared
19 S19 BC soil + 1.0% CaCl2+ 7.5% Alccofine-1203 Prepared
20 S20 BC soil + 1.0% CaCl2+ 10% Alccofine-1203 Prepared
Example 2:
INDEX PROPERTIES:
The influence of alccofine and CaCl2 on Atterberg limits (liquid limit, plastic limit, and shrinkage limit) of expansive soil is shown in Table. 7. Results show that liquid limit was decreased, and plastic limit increased with addition of Alccofine and CaCl2; hence the difference between liquid limit and plastic limit is the plasticity index. The plasticity is decrease with increase of alccofine-1203. The Plasticity index is reduced by about 75% when the soil is blended with 7.5% alccofine + CaCl2 1%. Mitchell (1993) suggested that plasticity is a good indicator of swell potential; that is, that a lower plasticity index reflects a lower swell potential. It is observed that the variation in Atterberg’s limits is marginal beyond addition of 7.5% of alccofine-1203. So, 7.5% alccofine-1203 can be called as fixation point, at which a considerable increase in soil workability. Changes in plasticity, with addition of Alccofine and CaCl2 are pozzolanic materials can be explained based on the double diffuse layer developed, and changes in the fabric of soil particles. With the addition of alccofine-1203 and calcium chloride to expansive soil, the following changes occurred: i) increase in the concentration of calcium ions and increase in the electrolyte concentration, and ii) exchangeable soils are replaced by calcium, leading to reduction in thickness of double diffuse layer (DDL) and cause flocculation of the clay particles. Both factors contribute to reduce in the liquid limit. Cation exchange and when soil is mixed with pozzolanic materials and cause improvement of soil plasticity (Locat et al., 1990). The negatively charged clay particles are balanced by the cations present in the double layer. Repulsive forces act on the particles when they come in to contact with each other and depend on the size of double layer. Any reduction in thickness of the double layer will reduce these repulsive forces. The addition of stabilizers to clay soils produces cation exchange reaction (substitution of the monovalent ions like Na+ by the Ca2+ ions), resulting in the depression on the double layer (Lambe and Whitman 2008). The fabric of the soil changes from relatively dispersed to flocculated arrangement which increases the liquid limit. Reduction in the liquid limit shows that the effect of reducing in the liquid limits dominants over the effects to change in the fabric. However, these two effects are known to increase the plastic limit of soil with addition of alccofine-1203 and calcium chloride. It is also well known that the plastic limit is the minimum water content when soil approaches certain shear resistance in the remolded positions. Addition of calcium chloride to soil increases the charge concentration (Ramana murthy, V., 2009). It is also observed that the shrinkage limit of soil– binder mixtures shows increases with increases of addition of stabilizers. This increase in the shrinkage limit with binder content is an indication of resistance to volume change due to the cementation of the clay particles.
Example 3:
COMPACTION CHARACTERISTICS:
The compaction characteristics of intrinsic soil and chemically blended soils are shown in table 7. The results of compaction shows that the maximum dry density is increases from 15.39 kN/m3 to 15.78 kN/m3 and optimum moisture content is reduced from 22.95% to 22% with increase of 7.5% alccofine-1203 and 1%CaCl2 binder; that is, for sample which shows maximum strength. Similar behavior of OMC and MDD was observed GGBS or industrial waste were used as stabilizing agents (Phani kumar., 2007 and sivapullaiah., 2015). Increase in dry density for a given compaction effect is desirable for use as construction materials as it indicates soil improvement (Basha et al., 2005). However some researches have noted different trends in the MDD and OMC for GGBS, fly ash and other types of ashes, like practical like rice husk ash (Ramana murthy V and Praveen G., V., (2007) observed a decrease in MDD and increase in OMC for some typical soils stabilized with CaCl2. Phanikumar B., R. and Nagaraju T., V., (2018) found both cement and GGBS resulted in a reduction of OMC and increased MDD. Rajesh Prasad Shukla and Niraj Singh Parihar (2016) also reported a decrease in the OMC and increase in the MDD with increasing micro fine slag.
[00075] Soil contains a higher percentage of clay exhibits lower resistance to compact efforts by Phani kumar and Sharma - 2007. The binder consists of a mixture of alccofine-1203 and calcium chloride, with more than 35% silt size particles. When non- plastic silt size particles are added, resistance is reduced for the same compacting effort. The flocculation of the soil particles indicates that the soil-binder mixtures can compacted at lower water content, resulting in a reduction in the optimum moisture content. At the same time, the particles come closer due to decreases in repulsion between the clay particles, resulting in the higher density even at lower water content. Furthermore, the addition of percentage of binder content by volume to the soil makes the mixture well graded, resulting in an increase in the maximum dry density.

[00076] Example 4:
UNCONFINED COMPRESSIVE STRENGTH:
The Unconfined compressive strength of soil mixed and compacted to their respective optimum moisture content and maximum dry density with alccofine-1203 and CaCl2 are presented in Table 7.
[00077] Unconfined compressive strength (UCS) tests were conducted with alccofine-1203 and CaCl2 were added independently and blended to the expansive soil samples. The UCS value for intrinsic soil is very sensitive clay soil was 103.96 kPa. The percentage of alccofine-1203 (2.5%, 5%, 7.5%and 10%) and CaCl2 (0.25, 0.5 and 1.0%) were added by dry weight of the soil. It is also observed that from table 7 that there is an increase in UCS values of mixes immediately after the addition of admixtures to the soil, but a reduction in strength after getting optimum unconfined compressive strength of 1572 kPa at 28 days with the 1% CaCl2 and 7.5% alccofine-1203 to soil under saturated and no swelling condition. The curing period of samples taken as 0, 14, 28 days. The process of curing period, aluminum cover file is wrapped to the soil samples and kept in desiccation chamber for required number of days. It was noticed that the reduction of plasticity could be attributed to the cation exchange reaction by alccofine-1203 and CaCl2. The optimum increase was noticed at 7.5% of alccofine-1203 and 1% of CaCl2. It is evident from the table 7 both the swell potential and swell pressure is nullified while retaining high unconfined compressive strength value. The UCS was increase from 103.96 kPa to 1572.05 kPa at 28 days curing for a combination 7.5% alccofine-1203 with 1% of CaCl2 at 28 days of curing. Beyond 7.5% of alccofine-1203 and 1% of CaCl2 with soil, the UCS value was slightly decreased.
[00078] This trend is similar for all the curing period. The pozzolanic reaction is a time dependent process which occurs between calcium and silica, and the results in the formation of cementitious compounds such as calcium-silicate-hydrates (C-S-H), calcium- aluminate-hydrates (C-A-H), and calcium-aluminium-silicate-hydrate. The formation of these cementitious compounds in the soil-binders mix is responsible for the increase in the unconfined compressive strength of stabilized soil.
[00079] Contrary to earlier researches, the addition of binder beyond 7% of alccofine-1203 gave a reduction in strength. The reduction in the compressive strength of soil once the binder/stabilizer content has exceeded a certain level has been reported by Rajesh Prasad Shukla, 2016. Therefore, based on the unconfined compressive strength behavior with addition of 1% CaCl2 and 7.5% alccofine-1203 binder is recommended as an optimum content of effectively stabilize to this expansive soil.
[00080] Example 5:
SWELLING BEHAVIOR:
The swell behavior of soil and mixed with different percentages of alccofine-1203 and CaCl2 is presented in Table. 7. The swell potential of intrinsic soil is 33.22% and swell pressure is 230 kPa. The swell of intrinsic soil is mainly due to presence of montmorillonite mineral. With addition of various percentages of alccofine-1203 and CaCl2, swell of soil decreases gradually and completely brings to zero with addition of alccofine 7.5% with 1% of CaCl2. In artificial soil with 7.5% alccofine with 1% of CaCl2, complete elimination of swell is due to availability of adequate calcium, cation exchange reaction and for the formation of pozzolanic reaction compounds. Pozzolanic reaction binds the flocculated soil particles, and thereby, formation of strong flocculated fabric, leading to the reduction in swell of soil. The swell potential of soil in water is measured in terms of expansivity and related with diffused double later (DDL), and changes in fabric (Holtz and Gibbs, 1956).
[00081] FSI decrease significantly with increases in the alccofine-1203 content. This is due to the reduction in diffused double layer (DDL). The free swell index is reduced from 81.82 % to zero with addition of admixtures 7.5 % of alccofine-1203 and 1% of CaCl2, the swelling of soil is moderately decreased, and it bring it to no swelling condition. Beyond 7.5 % alccofine-1203 the free swell index is slightly increased.
[00082] Example 6:
Other Parameters:
SPECIFIC SURFACE AREA:
Specific Surface Area is developed and recommended by Amy cerato - 2002. To determine SSA was conducted on oven-dried soil. All soil samples were first air-dried and pulverized. Place approximately one gram of oven dried soil passing a #40 sieve in the bottom of a clean, dry aluminum or glass tare having dimensions of approximately 76 mm in diameter by 20 mm in height. The mass of the soil was determined using an electronic balance with 0.001 gm accuracy. Approximately 3 ml of laboratory grade Ethylene Glycol Monomethyl Ether (EGME) was added to the soil with a pipette and gently mixed by hand with a swirling motion to create slurry. Place the tare into a vacuum desiccator and place a small Plexiglas lid over the tare, leaving a gap of 2-3 mm between the lid and the tare. Attach the lid of the desiccator to a vacuum pump and being evacuating using a vacuum of at least 635mm Hg. After 8-10 h, remove the tare and determine the mass of the soil/ EGME mixture. Repeat same procedure after a period of between 18 and 24 hours. This method was considered sufficiently accurate since the mass did not vary more than 0.001 grams. The specific Surface Area of the kaolinite, ranges of 35 to 70 m2/g have been reported. The Specific Surface Area of illite, ranges of 65 to 100 m2/g have been reported.
[00083] A montmorillonite mineral external Specific Surface Area of 50 to 120 m2/g and internal Specific Surface Area of 700 to 850 m2/g by Mitchell - 1993. The Specific Surface Area of the intrinsic soil is 92m2/g. The Specific Surface Area was reduced from 92m2/g to 51.5m2/g when the soil is blended with 7.5% of alccofine-1203 + CaCl2 of 1%. The specific surface area values for intrinsic soil and chemical blended soils are presented in table.8.
[00084] SURFACE AREA ACTIVITY:
Surface Area Activity is defined as:
SAA = SSA/CF
Where:
SAA = Surface Area Activity (m2/%g), SSA = Specific Surface Area (m2/g), CF = Clay fraction (%)
[00085] The Surface Area Activity is presented in Table 8 shows a SAA, total two groups are present based on specific surface area and clay fraction. First group is SAA is greater or equal to 8.0, which would, indicates that these soils are montmorillonitic, second group of SAA of 1.0 and 0.5, which would indicate the soils have mineralogy similar to that of kaolinite is reported by Amy Cerato, b., 2001. Therefore, based on the Surface area activity the addition of 7.5% alccofine-1203 and 1% of CaCl2 binder is presented in kaolinite group and recommended as of effectively stabilize to this expansive soil.
[00086] CATION EXCHANGE CAPACITY:
The Cation Exchange Capacity (CEC) is developed and recommended by Mokeagus, J.A. Exchangeable cations (i.e.Ca, Mg. Na, and K) determined displacing these from soil colloids with NH4. This is done by shaking the soil with 1N NH4OAc adjusted to pH 7.0. The CEC of intrinsic soil is 83.65 milliequivalents per 100g. The CEC was reduced from 48.165meq/100g to 43.63 meq/ 100g. The base exchange of cohesive non-swelling (CNS) materials was 37meq/100g of soil for 2-micron clay fraction by Katti, 1975. The cation exchange capacity of the kaolinite, values of 3 to 15 meq/100g has been reported. The cation exchange capacity of illite, values of 10 to 40 meq/100g has been measured. The mineral of the montmorillonite has the octahedral sheet sandwiched between two silica sheets. The bonds are weak and easily separated by cleavage or adsorption of water or other polar liquids. There is extensive substitution for aluminium and silicon within the lattice by other cations. Because of large amount of unbalanced substitution in the minerals, that exhibit high cation exchange capacity, generally in the range of 80 to 150 meq/100g (Sridharan, A., 1990). The cation exchange capacity values for intrinsic soil and chemical blended soils are presented in table.8. Therefore, based on the CEC value with addition of 1% CaCl2 and 7.5% alccofine-1203 binder is recommended as a cohesive hard soil (CHS) effectively stabilize to this expansive soil.
[00087] CATION EXCHANGE CAPACITY ACTIVITY:
Cation Exchange Capacity Activity is defined as:
CECA = CEC/CF
Where CECA = Cation Exchange Capacity Activity (meq/%*100 gms), CEC = Cation Exchange Capacity (meq/100 gms) and CF = Clay fraction (%)
It can be seen from table 8 that all samples have CECA less than 1.0. For a constant mineralogy, it would be expected that as CF increases, CEC would also increase and therefore CECA would be a constant (Davidson and Sheerer 1952).
ACTIVITY:
Atterberg’s limits for a soil are related to the amount of the water that is attracted to the surface of the soil particles (Lambe and Whitman 1969). The activity values for intrinsic soil and chemical blended soils are presented in table.8. It may be expected an amount of attracted water will be largely influenced by the amount of clay that is present in the soil and therefore surface area should be influenced as well. Based on this reasoning, skempton (1953) defined a quantity termed Activity:
Activity = PI/CF
Where: PI= Plasticity Index; CF = Clay Fraction.
Sensitivity (St): Clays who are having been heavily over-consolidated during their geological history (e.g. London clay) are insensitive. Also, are most boulder clays. There seem to be few examples of clay of low sensitive, but sensitivities of 2 to 4 are very common among normally consolidated clays and sensitivities of 4 to 8 are quite frequently encountered. A special category of extra sensitive clays, and found typically in the same localities, is the group of the so-called “quick-clays” which become so extremely soft on remolding as to appear practically fluid. The most extreme case which has been investigated relates to clay from St. Thuribe, near Quebec (Peck et. al. 1951), with a sensitivity of about 150.

Table7. Index and Engineering properties of Expansive soil
Samples Gs Sand (%) Silt (%) Clay (%)
Wn (%) LL (%) PL (%) SL (%) PI (%) MDD
(kN/m3) OMC (%) UCS (kPa) S (%) Sp (kPa)
0d 14d 28d
S1 2.68 14.86 29.79 55.35 46.0 70.00 18.00 8.34 52.00 15.39 22.95 103.96 73.69 65.14 33.22 230
S2 2.71 13.07 32.17 54.76 43.0 62.15 22.35 10.38 39.80 15.45 22.20 140.96 306.56 415.10 17.14 204
S3 2.77 12.65 33.33 54.02 39.0 56.80 22.36 14.32 34.44 15.58 21.00 171.95 1438.25 1156.94 12.15 170
S4 2.82 11.86 34.49 53.65 38.0 56.00 24.99 20.94 31.01 15.56 22.01 117.99 934.45 1828.31 9.41 150
S5 2.85 10.32 36.67 53.01 37.5 55.50 24.37 21.5 31.13 15.52 22.60 117.73 921.25 1008.90 9.50 125
S6 2.72 14.31 31.33 54.36 40.0 67.80 21.53 10.84 46.27 15.51 22.30 109.25 250.98 354.20 24.99 160
S7 2.71 12.87 33.35 53.78 35.0 62.17 22.00 19.54 40.17 15.53 22.50 125.06 425.75 568.20 17.51 140
S8 2.89 12.07 34.95 52.98 32.5 58.10 25.25 21.70 32.85 15.57 22.01 143.06 771.00 1157.15 10.75 110
S9 2.82 11.76 35.63 52.61 32.0 56.23 27.15 23.00 29.08 15.68 21.30 144.83 786.41 1619.12 7.89 075
S10 2.71 10.75 37.15 52.1 31.6 53.25 28.68 25.60 24.57 15.88 20.05 134.45 721.05 1601.87 5.30 045
S11 2.73 14.15 32.5 53.35 43.0 59.10 23.70 15.20 35.40 15.49 21.60 183.40 380.68 398.13 13.00 110
S12 2.83 13.18 34.48 52.34 36.0 57.10 23.90 15.25 33.20 15.38 25.70 186.62 572.50 701.20 11.03 095
S13 2.73 12.54 35.57 51.89 34.4 55.75 25.85 15.81 29.90 15.10 25.30 197.52 986.74 958.70 8.61 076
S14 2.75 11.89 36.79 51.32 31.0 53.15 23.29 18.49 29.86 15.35 24.20 208.26 1147.97 1112.05 8.58 034
S15 2.81 10.55 38.88 50.57 29.0 52.32 26.94 17.70 25.38 15.57 23.55 143.69 812.72 595.05 5.77 022
S16 2.77 14.1 32.66 53.24 41.0 58.80 30.51 16.50 28.29 15.31 24.70 187.06 398.16 412.20 7.52 065
S17 2.86 13.05 34.17 52.78 38.6 54.15 31.75 11.79 22.40 15.44 23.85 202.33 453.56 451.30 2.53 038
S18 2.76 12.35 35.55 52.10 36.0 51.10 32.50 16.47 18.60 15.51 23.15 247.93 852.58 892.40 0.34 015
S19 2.83 11.34 36.56 52.10 33.0 47.50 34.50 22.25 13.00 15.78 22.03 302.64 1117.17 1572.05 0 0
S20 2.85 10.15 38.5 51.35 32.0 47.00 33.00 22.76 14.00 15.71 21.40 212.93 1110.71 1443.65 0 0

Abbreviations: Gs = Sp. Gravity, Wn= Natural water content, LL = Liquid limit, PL = Plastic limit, SL = Shrinkage limit, PI = Plasticity index, MDD = Maximum dry density, OMC = Optimum moisture content, UCS = Unconfined compressive strength, S = Swell potential, Sp= Swell pressure.
Table 8. Properties of Expansive soil
Samples FSI (%) FSR Activity WA (%) Sensitivity USCS Void Ratio (e) Porosity (n) CEC
meq/100g CECA SSA
m2/g SAA
S1 81.82 1.80 0.93 63.70 3.48 CH 0.74 0.42 83.65 1.511 92.00 1.66
S2 72.00 1.72 0.72 56.42 3.38 CH 0.75 0.42 69.99 1.278 77.60 1.41
S3 54.00 1.54 0.63 51.68 3.18 CH 0.77 0.43 60.68 1.123 68.24 1.26
S4 77.27 1.77 0.57 50.96 2.86 CH 0.81 0.44 59.29 1.105 66.80 1.24
S5 52.17 1.52 0.58 50.50 2.87 CH 0.83 0.45 58.42 1.102 65.90 1.24
S6 55.00 1.55 0.85 61.69 2.76 CH 0.75 0.43 79.82 1.468 88.04 1.62
S7 69.56 1.69 0.74 56.42 2.43 CH 0.74 0.42 70.02 1.302 77.60 1.44
S8 50.00 1.50 0.62 52.78 2.04 CH 0.85 0.46 62.94 1.188 70.40 1.32
S9 40.01 1.40 0.55 50.96 1.87 CH 0.79 0.44 59.69 1.135 66.80 1.27
S10 45.02 1.45 0.47 48.41 1.72 CH 0.70 0.41 54.50 1.046 61.76 1.18
S11 55.01 1.55 0.66 53.78 3.53 CH 0.76 0.43 64.68 1.212 72.38 1.35
S12 44.44 1.44 0.63 51.87 2.60 CH 0.84 0.45 61.20 1.169 68.60 1.31
S13 44.44 1.44 0.57 50.73 2.28 CH 0.80 0.44 58.85 1.134 66.35 1.27
S14 38.88 1.38 0.58 48.36 2.17 CH 0.79 0.44 54.33 1.059 61.67 1.20
S15 40.00 1.40 0.50 47.61 1.61 CH 0.80 0.44 52.88 1.046 60.17 1.19
S16 45.00 1.45 0.53 53.50 2.63 CH 0.81 0.44 64.16 1.205 71.84 1.34
S17 38.88 1.38 0.42 49.14 2.36 CH 0.85 0.46 56.07 1.062 63.2 1.19
S18 25.01 1.25 0.35 46.41 1.93 CH 0.77 0.43 50.76 0.974 57.80 1.10
S19 0 1.0 0.25 43.22 1.16 CI 0.79 0.44 44.50 0.854 51.50 0.98
S20 15.00 1.15 0.27 42.77 1.25 CI 0.81 0.45 43.63 0.85 50.60 0.98
Abbreviations: FSI =Free swell index, FSR = Free swell ratio, WA = Water absorption, USCS = Unified soil classification system, CEC = Cation Exchange capacity, CECA = Cation Exchange Capacity Activity, SAA = Specific Surface Area, SAA = Specific Area Activity.
Table.9. Index Properties of Expansive soil

Samples IC IS IF IT IL Cc
SR
PSC Degree of Plasticity
S1 0.46 61.70 22.50 2.31 0.53 0.42 1.53 High Highly plastic
S2 0.48 51.80 18.0 2.21 0.51 0.36 1.54 High Highly plastic
S3 0.51 42.50 17.30 1.99 0.48 0.32 1.55 Marginal Highly plastic
S4 0.58 35.10 17.0 1.82 0.42 0.32 1.55 Marginal Highly plastic
S5 0.57 34.0 16.50 1.88 0.42 0.31 1.55 Marginal Highly plastic
S6 0.60 57.0 21.50 2.15 0.39 0.40 1.55 Marginal Highly plastic
S7 0.67 42.60 20.20 1.98 0.32 0.36 1.55 Marginal Highly plastic
S8 0.77 36.40 18.50 1.77 0.22 0.33 1.55 Marginal Highly plastic
S9 0.83 33.20 16.30 1.78 0.16 0.32 1.56 Marginal Highly plastic
S10 0.88 27.70 16.0 1.53 0.11 0.30 1.58 Marginal Highly plastic
S11 0.45 43.90 17.80 1.98 0.54 0.34 1.54 Marginal Highly plastic
S12 0.63 41.90 17.40 1.90 0.36 0.32 1.53 Marginal Highly plastic
S13 0.71 39.90 16.70 1.79 0.28 0.32 1.51 Marginal Highly plastic
S14 0.74 34.70 15.80 1.89 0.25 0.30 1.53 Marginal Highly plastic
S15 0.91 34.60 15.30 1.65 0.08 0.29 1.55 Marginal Highly plastic
S16 0.62 42.30 17.50 1.61 0.37 0.34 1.53 Marginal Highly plastic
S17 0.69 42.40 16.20 1.38 0.30 0.30 1.54 Marginal Highly plastic
S18 0.81 34.60 15.10 1.23 0.18 0.28 1.55 Low Highly plastic
S19 1.11 25.30 14.50 0.89 -0.11 0.26 1.57 Low Medium plastic
S20 1.07 24.20 14.40 0.97 -0.07 0.25 1.57 Low Medium plastic
Abbreviations: IC = Consistency index, IS = Shrinkage index, IF = Flow index, IT = Toughness index, IL = Liquidity index, CC= Compression index, SR = Shrinkage ratio, PSC = Potential swell classification.
[00088] Example 6:
MICRO-ANALYSIS:
Mineralogical analysis:
XRD (Fig 1) analysis has been carried out to confirm the formation of new minerals which can play a significant role in the addition of calcium chloride and alccofine-1203 in the treated soil with curing period. The hydration products as results of pozzolanic reactions primarily consist of C-S-H gel and calcium hydroxide (CH) (Diamond, 2004). The most important peak traced were related to CH which were identified at 2?=26° to 36° (Sayed hessam bahmani et al, 2016). As shown in figure 1 (a, b, c and d), diffraction peaks of C-S-H gel, Q and CH was found to vary noticeably. The sharp peaks in the XRD analysis indicates the represents of quartz (Q) which is crystalline in structure. The diffraction peak for calcium silica hydrates is observed at diffraction angle, 2?, equalling to 23° and 50° for natural soil in figure 1a. The XRD analysis also shows the additional peaks of calcium hydroxide (CH), Quartz (Q), are formed due to cementations reaction (Solanki and Zaman, 2012). It can be seen from figure 1c, the addition of alccofine-1203 of 7.5% and calcium chloride of 1% in the soil causes Q and CH related peaks are appeared at 2?. However, peaks corresponding to a cementation compounds are enhanced with an increase in curing period. Alteration and formation of minerals in the presence of calcium presents in treated soil with addition of alccofine-1203 and calcium chloride at 28 days of curing period as shown in figure 1c. Similar observation was made by (Anil kumar sharma and Sivapullaiah, P., V., 2015) for stabilization of clay with GGBS and fly ash. The intensity has increased for calcium chloride and alccofine-1203 treated when compared with the clay soil, which is all evident from X-ray diffraction data.
[00089] Example 7:
Microstructural studies:
Scanning Electron Microscopy (SEM) images have been captured to scrutinize the significant role of microstructural changes on the swell and compressibility of alccofine-1203 and calcium chloride treated with different proportions to soil at different curing period. In the presence of alccofine-1203 and calcium chloride, the sample reveals clearly visible aggregations (Fig 2c.e, g). The formation of aggregation or flocs is mainly responsible for the reduction of the swelling in expansive soil (Al-Rawas, 2002). Cement hydration materials such as C-S-H gel is mixed with calcium hydroxide, aggregation can be observed in the SEM-micrograph. The hydration products are usually intermixed with pore spaces that are not empty but occupied by hardened epoxy resin (Dimond, 2004). Alccofine- 1203 of 7.5% and calcium chloride of 1% treatment to the soil leads to the formation of compacted and strong soil matrix with curing period of 28 days (Fig 2e). However, the presence of calcium and magnesium causes an alternation in the microstructure with formation of portlandite can be observed in the micrograph (Fig 2e). Further, chemical composition analysis confirms the formation of cementitious compounds showing increase in percentage of calcium content (Table.10). As shown in table 10, formation of calcium carbonate is more evident in the soil binder mixtures in the presence of alccofine-1203 of 7.5% and CaCl2 of 1% in the soil.
Table10. Chemical compositions in terms of atomic weight percentage of expansive soil and chemical treated soil at different curing period.

Combinations
days
C %
O % Mg
%
Al %
Si % Ca
% Au
% Fe
% K
%
soil 0 --- 43.66 1.25 10.75 28.64 -- 9.8 4.6 1.3
Soil + 5%
alccofine 0 8.09 53.6 1.36 8.40 20.85 2.9 4.8 -- --
Soil + 1% CaCl2
+7.5% alccofine 28 20.9 45.97 1.37 8.21 17.45 6.1 -- -- --
Soil + 1% CaCl2
+10% alccofine 28 14.6 48.7 1.48 9.04 19.28 6.9 -- -- --

Abbreviations: C=CaCo3, O=SiO2, Mg=MgO, Al= Al2O3, Si= SiO2, Ca= Wollastonite.
[00090] Now, the crux of the invention is claimed implicitly and explicitly through the following claims.
[00091] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the “invention” may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the “invention” will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[00092] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to a claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in or deleted from, a group for reasons of convenience and/ or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
[00093] While embodiments of the present invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the invention, as described in the claim.