Use of Bio-enzymes and Natural Adhesives for Improvement of Geotechnical Properties of Black Cotton Soils

Use of Bio-enzymes and Natural Adhesives for Improvement of Geotechnical Properties of Black Cotton Soils | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Use of Bio-enzymes and Natural Adhesives for Improvement of Geotechnical Properties of Black Cotton Soils Guruprasad Ajay Chavan, Purnanand P Savoikar This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7142521/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Black cotton soil, are expansive in nature, posing challenges for construction activities. Structures resting on these soils may crack and sink as a result of the soils' seasonal expansion during the monsoon and contraction during the summer. Special techniques such as soil stabilization, the use of deep foundations, and proper drainage systems are employed to mitigate the effects of swelling and prevent damage to buildings. In the present study, the extensive literature survey is conducted on different type of stabilizers such as various fibres, agricultural by-products, industrial by-products, chemical stabilizers, natural adhesives, and bio-enzymes used for improvement in geotechnical properties of black cotton soils. The natural adhesives Xanthan gum and bio-enzyme Terrazyme are used for this research study to enhance the black cotton soil collected in Kolhapur, Maharashtra, India. Both compounds were found to increase the qualities of black cotton soil, including plasticity, California bearing ratio, and unconfined compression strength. When compared to Terrazyme, Xanthan gum increases unconfined strength at a dose of 1% of soil mass. Terrazyme dose of 1.5 ml per 100 ml of water enhanced the California bearing ratio by 76.32%. Terrazyme and Xanthan gum are effective in increasing soil adhesion and forming dense masses, but Xanthan gum may pose challenges in the field due to its potential for difficulties in mixing. black cotton soil characterization improvement stabilization Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 1. Introduction Expansive soil, such as black cotton soil, behaves differently depending on the proportion of different minerals present. Black cotton soil's high clay content causes it to shrink and swell in response to moisture changes, resulting in cracks and damage to structures built on it. To address this issue, various techniques such as soil stabilization and proper drainage systems are used during construction. Globally, expansive soils are present; in certain countries, the proportion of land covered by these soils is displayed in Fig. 1 . Expansive soils, also known as black cotton soils, expand when moisture levels rise, owing primarily to the clay mineral montmorillonite. These soils, predominantly black and abundant in cotton cultivation, are found in states like Maharashtra, Gujarat, Uttar Pradesh, Rajasthan, Madhya Pradesh, Andhra Pradesh, and Chennai. They cover over 0.8 x \(\:{10}^{6}\text{s}\text{q}.\text{k}\text{m}\) , or over one-fifth of the nation [ 2 ]. The colour of black cotton soil ranges from reddish brown to black. They are found at depths of 0.50 to 10 meters and have a high compressibility. The typical characteristics of the soil are listed in Table 1 . Table 1 Typical characteristics of Black cotton soil (Nayak, 2015 [ 3 ]) Sr. No. Property Value 1 Grain size distribution Gravel 0 to 10% Sand 15 to 25% Silt 15 to 30% Clay 25 to 70% 2 Consistency limits Liquid limit 50 to 120% Plastic limit 30 to 60% Plasticity index 20 to 60% Shrinkage limit 8 to 18% 3 Soil Classification CI or CH or MH 4 Specific gravity 2.60–2.75 5 pH value 8 to 10 6 Organic content 0.4 to 2.4% 7 Differential free swell (DFS) 40–180% 8 Swelling pressure 50–800 kN/m² As per IS:2911 (Part III)-1980 [ 4 ] Annexure - A and Holtz and Gibbs [ 5 ], black cotton soils are classified as having low degree of expansiveness (DFS less than 20), moderate expansiveness (DFS between 20 to 35), high expansiveness expansiveness (DFS between 35 to 50) and very high expansiveness (DFS greater than 50). This indicates that as per Table 1 , these soils can be classified as soils with moderate to very high expansiveness. Black cotton soil is considered critical soil from the point of view of construction on it. Hence, analysis and improvement of soil are necessary and also requirements of the construction field. Many researchers have studied black cotton soil in the past and evaluated it with different stabilization techniques. Lime stabilization, cement stabilization, and chemical stabilization are examples of these techniques. The process of adding lime to soil to improve its properties such as increasing strength and reducing plasticity is known as lime stabilization. Cement stabilization, is mixing cement with soil to increase compressive strength while decreasing expansiveness. Finally, chemical stabilization entails the application of different chemicals to change the qualities of the soil and make it appropriate for building. These stabilizing procedures have been shown to be helpful in reducing the probable damages caused by black cotton soil and assuring the stability and durability of various civil engineering structures erected on it. 2. Literature Review In the present study, a detailed review of literature on stabilization of black cotton soils using conventional stabilizers, fibres, agricultural and industrial waste, chemical stabilizers, natural adhesives and bioenzymes is undertaken. 2.1 Black cotton soil Stabilization by Conventional Stabilizers, Fibres, Agricultural and Industrial Waste Kumar et al. [ 2 ] found that increasing lime content reduces the maximum dry density of soil-lime mixes while increasing moisture content increases. When fly ash is added to soil-lime mixtures, the maximum dry density decreases while moisture content increases. The strength of fly ash-soil-lime-fibre mixtures increases with the percentage of fly ash while the lime content remains constant. The recommended lime content and fly ash content are 8 and 15%, respectively. Fibres increase both unconfined compressive strength and split tensile strength. Babu et al. [ 6 ] a study in Davangere district, Karnataka, used tri-axial shear tests, swelling tests, and consolidation tests to evaluate the strength, swelling, and compressibility of black cotton soil reinforced with coir fibres. The results showed that using coir as a random reinforcing material can improve engineering behavior and coir fibres reduced the swell potential of black cotton soil and reduced the compression index due to fibre inclusion. In Xinxiang, China, Tang et al. [ 7 ] investigated the behavior of expansive soil reinforced with synthetic polypropylene monofilament fibres. It was reported that the increased fibre concentration causes the stress-strain curve to shift from a strain-softening to a strain-hardening type, and soil reinforced with fibres has an undrained strength that is sensitive to water content, increasing by 105% when the water content is lowered. Elayaraja and Arumairaj [ 8 ] analyzed black cotton soil from Coimbatore, India, using two methodologies to evaluate the strength behavior geosynthetics reinforced soil. It was observed that the introduction of non-woven geotextiles increased the shear strength of black cotton soil, making it suitable for drainage, filtration, fine particle separation, embankment geomembrane, and the structures like flyovers. Clayey soil specimens reinforced with discrete coir fibres were investigated by Babu and Chouksey [ 9 ], who also carried out numerical simulations of triaxial compression tests on clay specimens reinforced with fibres. It was shown that adding fibres to the soil strengthens its ability to respond to stress and strain in clayey soils. Srivastava et al. [ 10 ] found that adding 30–50% shredded tire waste to black cotton soil reduced its volume change potential and shear strength, suggesting it can be used as a backfill material in mixing, walls to lower backfill pressure and minimize swelling and shrinking. Expansive soil from the Banda district in Uttar Pradesh, India was examined by Ashango et al. [ 11 ] and stabilized with steel slag, rice husk ash, and quick lime. The optimum mix of these elements was found to be expansive soil, steel slag, rice husk ash, and quick lime at 65, 20, 5, and 10%, respectively. The soil plasticity decreased to 66.2%, while its strength increased to 96%. The mixture was shown to be as durable as the sub-grade material, with its dynamic characteristics increasing soil stiffness by 58–78%. Gobinath et al. [ 12 ] explored the use of precipitated silica (PS) from rice husk to enhance the geotechnical engineering properties of black cotton soil. The optimal PS content of 50% is recommended for improving the sub-grade characteristics of the soil for pavement layer use. Dalal et al. [ 13 ] used agricultural and industrial waste to stabilize black cotton soil using a combination of bagasse ash, ground granulated blast furnace slag (GGBS), and wood powder. Wood powder effectively controlled swelling in the soil, up to 58%. Bagasse ash and GGBS improved the strength of the soil sample, with GGBS and bagasse ash contributing more to strength and wood powder for swelling control. Etim et al. [ 14 ] investigated the stabilization of black cotton soil in Gombe State, Nigeria, utilizing up to 8% lime with up to 10% iron ore tailing (IOT). The study also examined the leaching potential of iron from the soil-lime-IOT mixes, indicating its usefulness as a sub-base material for light trafficked roads. 2.2 Chemical Stabilization of Black Cotton Soil Uppal and Chadda [ 15 ] examined the chemical and physical alterations that occur when lime is used to stabilize Indian black cotton soils. It was discovered that clay particles smaller than 0.002 mm aggregate into larger particles (0.02–0.05 mm). With low lime concentration, this behavior is closely related to the aggregation of calcium hydroxide and other alkaline earth metals. Raychaudhuri et al. [ 16 ] presented generalized characteristics, and chemical analysis results of black cotton soils in India, as illustrated in Table 2 . Table 2 Characteristics with chemical analysis of Indian black cotton soil ( Raychaudhuri et al. 1963 [ 16 ] ) Sr. No. Properties Range of values 1 Clay and silt fraction 70–80% 2 Course sand 4–8% 3 pH 7.2–8.5% 4 Total solids 0.05–1.5% 5 Salt concentration depth 5–7 ft. 6 Acid solubles 1–10% 7 Cation exchange capacity (CEC) 40–60 meq /100 g 8 Exchange calcium 15–42% 9 Exchange magnesium 6–20% 10 Exchange K₂O 0.1–0.6% 11 Exchange sodium 3–13% 12 Fe₂O₃ 9–13% 13 A1₂O₃ 16–23% 14 R₂O₃ 25–36% 15 CaO 2.5-7% 16 MgO 3–4% 17 SiO₂ 50–55% Wild et al. [ 17 ] reported that Kaolinite clay with gypsum and lime exhibits high expansion when cured, but adding (GGBS) reduces this expansion and increases compressive strength. Adjusting the lime-GGBS ratio can modify both properties. The reduction in expansion is due to a balance between competing hydration reactions, which inhibits ettringite nucleation. Further research is needed to confirm this hypothesis using a wider range of compositions and micro-analytical methods. Asmaa et al. [ 18 ] examined the impact of lime stabilization on expansive clay in Victoria, Australia. The soil was treated with an optimum lime content (OLC) that reduced swell potential, and the soil-water characteristic curve (SWCC) was used to analyze the soil behavior. The soil specimens were tested under various stress levels and moisture ratios. The results showed that the soil was highly collapsible under higher suction pressures and less compaction stress. Additionally, significant swelling occurred under higher suction pressures and higher compaction stress. The study concluded that although the soil was treated with lime at the OLC, it was not highly collapsible under different stress levels. Oza and Gundaliya [ 19 ] improved the behavior of Rajkot region BC soil using three additives, with cement dust providing substantial and durable benefits as a stabilizing agent. The summary of the optimum dosage of three additives and their effect on plasticity and increment in compressive strength is presented as per Table 3 [ 19 ]. Table 3 Black cotton soil with identified optimum dosage of additive ( Oza and Gundaliya [ 19 ]) Sr. No. Type of Stabilizing agent Optimum Percentage used in BC Soil Plasticity Index Curing period for Compressive Strength (Days) Compressive Strength (N/ \(\:{\mathbf{m}\mathbf{m}}^{2}\) ) 1 Cement Dust 7% 11.15 28 17.47 2 Cement Dust + Lime 9% 9.25 28 14.46 3 Lime 8% 8.35 28 10.91 Das and Soni [ 20 ] investigated the effects of GGBS and lime on the hydraulic conductivity of expansive clay minerals such as kaolinite, montmorillonite, and illite clay. A study revealed that adding lime and GGBS reduces kaolinite's permeability, increasing hydraulic conductivity as time elapses. However, kaolinite's conductivity decreases due to GGBS and lime, possibly due to calcium silicate hydrate gel formation or decreased inter-aggregate pore size. Yi et al. [ 21 ] investigated the usage of carbide slag (CS) and ground granulated blast furnace slag (GGBS) to stabilize soft clay and compared it to Portland cement (PC). Scanning electron microscopy (SEM) micrographs (Fig. 2 ) of 30% GGBS stabilized clays with carbide slag/ground granulated blast furnace slag (C/G) ratios of 0.15 and 0.40 at 7 and 90 days revealed limited hydration and irregularly shaped calcium silicate hydrates (CSH) and cubical shaped calcium aluminate hydrates (CAH). Saride and Dutta [ 22 ] investigated the stabilization of expansive soils using class C fly ash to improve swelling, stiffness, and damping properties. It was reported that the normalized modulus degradation decreased with increased confining pressure and fly ash content, and the Poisson's ratio decreased with increased confining pressure and fly content. Verma et al. [ 23 ] chemical stabilization methods were categorized into four main subgroups as biochemical, electrochemical, inorganic pozzolanic/cementitious material, and organic polymeric binders, based on nature and chemical composition. Different methods were discussed by many researches for improvement of black cotton soil also assessed with various laboratory tests with changes in microstructure. These analyses are helpful for field applications as well as for further research. 2.3 Improvement of Black Cotton Soil by Natural Adhesives and Bio-Enzymes Chang et al. [ 24 ] found that Xanthan gum, a polysaccharide used as a food additive and rheology modifier, can significantly increase soil compressive strength when used with fine-grained soil. Xanthan gum bridges between distant particles, enhancing particle alignment and strength improvement, as shown in Fig. 3 . The most economical and efficient concentration for soil treatment is approximately 1–1.5%. Xanthan gum is recommended for soil improvement, especially for dry soil, with minimal adverse effects. Soldo and Miletic [ 25 ] investigated the impact of Xanthan gum on soil engineering properties using three mechanical tests as unconfined compression, unconsolidated undrained triaxial, and direct shear. Results showed that Xanthan gum improved the strength of all soil types, with the highest strength achieved for silty sand. The study also found that Xanthan gum increased cohesion in cohesionless soils but not friction angles. Begum et al. [ 26 ] discussed the use of Terrazyme, a universally available bioenzyme, for soil augmentation and stabilization. Laboratory tests showed that Terrazyme reduces clay content, increases coarser particles, decreases liquid and plastic limits, and increases maximum dry density. It also reduces the compressive index and coefficient of compressibility, making it a cost-effective solution for expansive soil intensification. 2.4 Critical appraisal of the literature The above used industrial waste, agricultural waste recovered materials, and other cementation materials using readily available stabilizing agents. Ground improvement alters soil properties, allowing for a variety of building processes. Shear strength, swelling and shrinkage properties, and bearing capacity are examples of these qualities. These strategies are increasingly being used in the building business where the soils have poor subsurface characteristics. The use of different fibres and agricultural by-products as soil amendments can enhance its strength and stability. Furthermore, the incorporation of natural adhesives, chemical stabilizers, and bio-enzymes can help alleviate issues such as shrinkage and swelling, ultimately making the soil more suitable for construction purposes. By examining the changes in microstructure through laboratory assays, this research provides valuable insights into the mechanisms behind soil improvement, which can inform future studies and guide the development of more efficient techniques and machinery for soil stabilization. Very less research work on improvement of black cotton soils using bioenzymes or biopolymers using curing is available. In the present study, a detailed experimental programme is undertaken to investigate effect of natural adhesive and bio-enzymes such as Xanthan gum and Terrazyme on geotechnical properties of black cotton soils in Kolhapur region. 3. Experimental programme Soil stabilization strategies are mostly determined by the nature of the stratum and the goal of development. Additives including lime, bitumen, fly ash, cement, and others are used on the site to enhance the characteristics of the soil. The study aims to improve black cotton soil in Kolhapur, Maharashtra, India, using natural adhesives Xanthan gum and bio-enzyme Terrazyme. Samples were collected from various regions of the city, and properties were analyzed at different depths. The study aims to address the expansion of the city limits and improve the soil's quality for future use. Figure 4 shows the location of the study area and all sampling locations [ 27 ]. 3.1 Geotechnical properties of Kolhapur black cotton soils Sampling was done at twenty eight different locations. Samples were collected from different depths below ground level as 0.5m, 1m, 1.5m, 2m, 2.5m 3.0m, 3.5m and at 4.0m.Various tests were conducted on samples collected as per the relevant Indian Standards and results were analyzed, soil Characteristics are listed in Table 4 (Chavan and Savoikar [ 27 ]). Classification of soil was done on the basis of plasticity chart with the help of soil test results. Table 4 Characteristics of black cotton soil in study area (Chavan and Savoikar [ 27 ]) Sr. No. Soil property Range of values 1 Mechanical analysis Sand 15 to 30% Silt and Clay 60 to 95% 2 Consistency limits Liquid limit (LL) 38.46–65.40% Plastic limit (PL) 22.0–51.71% Plasticity index(PI) 11.89-30% Shrinkage limit (SL) 9.15–16% 3 Soil classification CH-MH-CI 4 Specific gravity(G) 2.08–2.73 5 Field density 13.8-19.8kN/m³ 6 Dry density 10.45–14.80 kN/m³ 7 Proctor density 13.5–17.2 kN/m³ 8 Optimum moisture content (OMC) 13.50–20.90% 9 Differential Free swell (DFS) 20–60% 10 California bearing ratio (CBR unsoaked) 2.4–4.60% 11 Cohesion (c) 19.61–37.27 kN/m² 12 Angle of internal friction (φ) 8.75–24.32° 13 Unconfined compression strength 62.22–68.95 kN/m² 14 Compression index (C c ) 0.454–0.499 15 Recompression index (C r ) 0.030–0.033 The above soil samples were collected from 28 locations at three different sites. Table 5 shows the variation in differential free swell and expansiveness classification at these locations. Table 5 Differential free swell and expansiveness classification of soils in Kolhapur Sr. No. Location Differential Free Swell Expansiveness 1. Rankala 30 to 60 Moderate to very high 2. Line Bazar 40 to 60 High to very high 3. Ramnagar 40 to 50 High 4. Karande Mala, Tarabai Park 18 to 20 Low 5. Sugar Mill, Bawada 20 to 40 Moderate to high 6. Biranje Panand, Bawada 30 to 50 Moderate to high 7. Chambukhadi, Phulewadi 50 High 8. Ramnagar, near Dasara Chowk 50 High 9. Kandalgaon 40 High 10. Rankala 30 Moderate 11. Kaneriwadi 40 High 12. Shiroli 30 Moderate 13. Vathar 30 Moderate 3.2 Improvement using bio-enzymes Terrazyme is a non-toxic, natural liquid bio-enzyme mixture that changes the physical and chemical properties of soil. When Terrazyme is introduced in to the soil, it catalyzes the decomposition of organic molecules and enhances the soil particles' wetting and bonding ability. It enables soil materials to be wetter and more tightly compacted. Furthermore, better chemical bonding aids in the fusion of soil particles, resulting in a more permanent structure that is more resistant to weathering, abrasion, and water penetration. Some Terrazyme characteristics are mentioned in Table 6 below, as provided by the supplier. Table 6 Characteristics of Terrazyme (supplied by manufacturer) Sr. No. Identity Terrazyme 1 Hazardous Components None 2 Boiling point 212F 3 Specific Gravity 1.05 4 Melting point Liquid 5 Evaporation rate Same as water 6 Solubility in water Complete 7 Appearance/Odor Brown liquid, non-obnoxious 8 Conditions to avoid > 45°C ; pH below 3.5, above 9.5 9 Incompatibility Caustics, strong bases 10 Storing temperature below 45°C 4. Results and discussions The improvement in geotechnical properties of black cotton soil such as consistency limits, maximum dry density and optimum moisture content, unconfined compression strength and California bearing ratio has been evaluated by varying the dosage of Terrazyme and Xanthan gum is evaluated. The results are presented below: 4.2. Terrazyme as bio-enzyme type stabilizer The tests conducted were specific gravity, plastic limit, liquid limit, standard proctor test, California bearing ratio value (CBR), and unconfined compression test. Sampling was done up to a depth of 4.0 m in 4 different layers; hence, soil from 4.0m below ground level was mixed with Terrazyme. Soil was treated with different dosages i.e. 0.5 ml per 100 ml of water, 1.0 ml per 100 ml of water, 1.5 ml per 100 ml of water, 2.0 ml per 100 ml of water and 2.5 ml per 100 ml of water, and subjected to various tests. Curing is helpful in UCS and CBR testing as regards the strength development, simulating the field conditions and for obtaining consistent and reliable data. Proper curing allows for the full development of the soil's strength, particularly in stabilized soils where chemical reactions contribute to strength gain. Before curing, the soil sample is typically compacted to the desired density using a mould and compaction tool. The moisture content is adjusted to achieve the optimal compaction, often based on the Proctor test results. After compaction, the sample is carefully extracted from the mould and trimmed to the standard dimensions required for the UCS test, typically maintaining a height-to-diameter ratio of 2:1. For the UCS test on a saturated or near-saturated soil sample, the curing process involves maintaining the sample in a moist environment. This can be done by wrapping the sample in plastic film or placing it in a sealed container to prevent moisture loss. When soil samples are treated with stabilizers curing can last from 7 days to several months. This longer curing period allows chemical reactions to occur, significantly increasing the strength of the sample. 4.1.1 Influence of Terrazyme on consistency limits of black cotton soil Effect of Terrazyme on consistency of soil was analyzed and results were tabulated in Table 7 . Also, Figs. 5 and 6 show variation of consistency limits with different dosages of Terrazyme. It was observed that consistency limits decreased with addition of Terrazyme. Liquid limit decreased by 22.51%, plastic limit by 19.62% and the plasticity index by 39.35%. Table 7 Effect of Terrazyme on consistency limits of black cotton soil Sr. No. Dosage (ml)/100 ml of water Liquid Limit (LL) % Plastic Limit (PL) % Plasticity Index (PI) % 1 Untreated 62.20 45.20 17 2 0.5 54.37 40.12 14.25 3 1.0 50.51 36.33 14.18 4 1.5 48.53 38.22 10.31 5 2.0 48.32 37.57 10.75 6 2.5 48.20 37.43 10.77 4.1.2 Influence of Terrazyme on maximum dry density and optimum moisture content Effect of Terrazyme on maximum dry density and optimum moisture content is presented in Table 8 and Figs. 7 and 8 . It is observed that about 11.83% increase in maximum dry density and marginal decrease in OMC was observed. This is due to increased adhesion between particles and resulting densification of soil after addition of Terrazyme. Table 8 Effect of Terrazyme on maximum dry density Sr. No. Dosage(ml)/ 100 ml of water Maximum Dry Density (MDD ) kN/ m 3 Optimum Moisture Content (OMC) % 1 Untreated 16.90 13.00 2 0.5 17.20 12.50 3 1.0 17.30 12.00 4 1.5 18.90 12.00 5 2.0 18.50 12.50 6 2.5 18.20 12.50 4.1.3 Influence of Terrazyme on California bearing ratio value of black cotton soil Effect of Terrazyme on California bearing ratio value (CBR) was analyzed and results were tabulated in Table 9 . Also, Fig. 9 shows variation of California bearing ratio value with different dosage of Terrazyme with curing period. After seven days of curing with Terrazyme dosage of 1.5 ml per 100 ml of water, the California bearing ratio value increased by 76.32%. Table 9 Effect of Terrazyme on CBR value Sr. No. Dosage(ml)/ 100 ml of water California bearing ratio value (CBR) % Curing period (days) 0 07 1 Untreated 3.55 3.80 2 0.5 4.20 4.59 3 1.0 4.44 5.10 4 1.5 4.80 6.70 5 2.0 4.62 6.10 6 2.5 4.28 5.60 4.1.4 Influence of Terrazyme on Unconfined compression strength (UCS) of black cotton soil The effect of Terrazyme on the unconfined compression strength value was investigated, and the findings are shown in Table 10 . Figure 10 also depicts the fluctuation of unconfined compression strength with different Terrazyme dosages. It is observed that the unconfined compression strength increased by 57.89% with Terrazyme dosage of 1.5 ml per 100 ml of water after 7 days of curing. It was found that the optimum Terrazyme dose for stabilizing black cotton soil is 1.5 ml per 100 ml of water. It is observed that addition of Terrazyme results in increase of soil strength, more prominently after 7 days of curing. Table 10 Effect of Terrazyme on unconfined compression strength on curing Sr. No. Dosage(ml)/ 100 ml of water Unconfined compression strength (UCS) kN/m² Curing period (days) 0 07 1 Untreated 64.45 71.12 2 0.5 82.30 86.30 3 1.0 86.20 90.71 4 1.5 89.30 112.22 5 2.0 87.13 110.18 6 2.5 80.65 104.30 4.2 Xanthan gum as natural adhesives Xanthan gum is a polysaccharide produced by the xanthomonas campestris bacterium and used as a food additive and rheology modifier. It is composed of D-uronic acid, D-mannose, pyruvylated mannose, 6-O-acetyl D-mannose, and 1,4-linked glucan. Its pseudo-plasticity and high stability under various temperatures and pH make it a popular choice in food. Xanthan gum is also used in the oil industry as a drilling mud thickener and in concrete to increase viscosity and prevent washouts [ 24 ]. Xanthan gum, a hydrophilic polymer with a high molecular weight, is produced by the fermentation of carbohydrates in xanthomonas campestris . Black cotton soil was treated with different dosages of Xanthan gum i.e. 0.2%, 0.4%, 0.6%, 1.0%, 1.5% and 2.0% of soil. The soil which was treated with Terrazyme, the same soil is used for Xanthan gum treatment also. Effect of Xanthan gum on soil was analyzed on the basis of different laboratory tests such as standard proctor test, California bearing ratio value (CBR), and unconfined compression test (UCS). 4.2.1 Influence of Xanthan gum on maximum dry density and optimum moisture content of black cotton soil Standard Proctor tests were conducted on black cotton soil. Effect of Xanthan gum on maximum density of soil is tabulated in Table 11 . Also, Fig. 11 shows variation of maximum density with different dosage of Xanthan gum and Fig. 12 shows variation of moisture content. There is about 13.61% increase in maximum dry density after 1.5% dosage of Xanthan gum with marginal reduction in OMC values. Table 11 Effect of Xanthan gum on maximum dry density and optimum moisture content Sr. No. Dosage (%) of weight of soil sample Maximum Dry Density (MDD ) kN/ m 3 Optimum Moisture Content (OMC) % 1 Untreated 16.90 13.00 2 0.2 16.92 12.50 3 0.4 17.20 12.50 4 0.6 18.02 12.00 5 1.0 18.33 12.00 6 1.5 19.20 12.00 7 2.0 18.56 12.00 4.2.2 California bearing ratio value (CBR) of black cotton soil with Xanthan gum Effect of Xanthan gum on CBR value of soil is tabulated in Table 12 . Also, Fig. 13 shows variation of CBR value with different dosage of Xanthan gum. It can be seen that there is 89.47% increase in CBR value after 7 days of curing as compared to untreated black cotton soil. Table 12 Effect of Xanthan gum on California bearing ratio (CBR) value Sr. No. Dosage (%) of weight of soil sample California bearing ratio value (CBR) % Curing period (days) 0 07 1 Untreated 3.55 3.80 2 0.2 3.68 3.90 3 0.4 3.88 4.30 4 0.6 4.5 5.89 5 1.0 5.65 7.20 6 1.5 5.38 6.56 7 2.0 4.96 6.23 4.2.3. Unconfined compression strength (UCS) of black cotton soil with Xanthan gum The effect of Xanthan gum on the unconfined compression strength value was investigated, and the findings are shown in Table 13 . Also, shown in Fig. 14 is the fluctuation of unconfined compression strength with different dosages of Xanthan gum, which enhances soil strength and is more predominant with curing. It is observed that the unconfined compression strength of black cotton soil increases by 149.30% when mixed with 1% dosage of Xanthan gum. This occurs because there is direct interaction between fine particles and Xanthan gum strands due to electrically charged clay particles and Xanthan gum bridges the gap between distant particles, enhancing particle alignment and strength improvement. Similar results were reported by Chang et al. [ 24 ]. Table 13 Effect of Xanthan gum on cured unconfined compression strength Sr. No. Dosage (%) of weight of soil sample Unconfined compression strength (UCS) kN/m² Curing period (days) 0 07 1 Untreated 64.45 71.12 2 0.2 78.55 90.42 3 0.4 90.50 98.52 4 0.6 98.30 120.40 5 1 110.00 177.30 6 1.5 108.20 156.43 7 2 106.33 152.89 From the above discussions, it is observed that the strength of the soil (CBR and UCS) initially increases with the addition of Terrazyme up to 1.5 ml/100 ml and also for Xanthan gum, but then decreases beyond a certain point. This can be explained by the following factors: Optimal concentration effect Both Terrazyme and Xanthan gum have an optimal concentration range within which they are most effective in improving soil properties. In the initial phase (up to 1.5 ml/100 ml), the addition of Terrazyme enhances the bonding between soil particles and reduces voids, leading to an increase in soil strength. Similarly, Xanthan gum enhances soil cohesion and improves the strength by forming a gel-like matrix that binds the soil particles together. Over-stabilization or excessive additive content Beyond the optimal concentration, the addition of more Terrazyme or Xanthan gum can lead to over-stabilization, where the excess enzyme or biopolymer content starts to interfere with the natural bonding process. In the case of Terrazyme, excessive enzyme content might lead to an imbalance in the particle arrangement, creating more voids or disrupting the soil's natural structure, thus reducing its strength. For Xanthan gum, adding too much can lead to a situation where the soil becomes too flexible or overly lubricated, reducing its overall stiffness and strength. Saturation and dilution effects As the concentration of Terrazyme or Xanthan gum increases beyond a certain point, the soil may reach a saturation threshold where it can no longer effectively absorb or interact with the additives. This can dilute the stabilizing effect and reduce the efficiency of the additives in binding the soil particles, leading to a decrease in strength. Mechanical behaviour changes The mechanical behaviour of the soil can also change with higher concentrations of additives. For instance, Terrazyme may lead to excessive compaction or increased brittleness at higher concentrations, which can negatively affect the soil's CBR and UCS values. Similarly, excessive Xanthan gum can lead to a reduction in friction between particles, thereby decreasing the overall strength. 4 Conclusions The natural adhesives Xanthan gum and bio-enzyme Terrazyme were utilized to enhance the black cotton soil collected in Kolhapur, Maharashtra, India. The influence of the curing period was also considered, and samples were cured for 7 days. Both compounds were found to enhance the geotechnical properties of black cotton soil, including maximum dry density, plasticity index, California bearing ratio value and unconfined compression strength. This impact is particularly apparent after curing. Consistency limits decreased with addition of Terrazyme. Plasticity index was also decreased by 39.35%. A 12% increase in maximum dry unit weight was observed. After seven days of curing with a dosage of 1.5 ml per 100 ml of water, the California bearing ratio value increased by 76.31%. Unconfined compression strength increased by 57.79% with 1.5 ml per 100 ml of water dose, after 7 days of curing. It was found that the optimum Terrazyme dose for stabilizing black cotton soil is 1.5 ml per 100 ml of water. Xanthan gum increased the maximum dry unit weight by 13.61% when added 1.5% of soil mass. A seven-day period of 1.0% dosage curing resulted in an 89.47% increase in the California bearing ratio value. Additionally, after 7 days of cure with a 1.0% dosage, unconfined compression strength increased by 149.30%. It can be concluded that both Terrazyme and Xanthan gum can be used as stabilizer for black cotton soils to improve the geotechnical properties with optimum dosage of Terrazyme of 1.5 ml per 100 ml of water and Xanthan gum of dosage 1% by weight of soil treated. Though addition of Terrazyme improved the plasticity index, it was not possible to evaluate consistency limits after addition of Xanthan gum. Mixing of Terrazyme with soil was much easier as it was used along with water, mixing of Xanthan gum may be difficult at the site. Terrazyme and Xanthan gum are effective in increasing soil adhesion and forming dense masses, but Xanthan gum may pose challenges in the field due to its potential for difficulties in mixing. Limitation of the present study was restricting the sample collection from depths up to 4m. Based on the outputs obtained from the laboratory studies, field applications and practical difficulties can be studies and cost analysis can be done. The present study can be extended to greater depths by collecting samples from boreholes and studying effect of seasonal variation in moisture content on the geotechnical properties. Also, more detailed studies on consolidation and swelling behavior can be undertaken. Notations The following symbols are used in this paper: CBR = California bearing ratio (%) c = Cohesion (kN/m 2 ) C c = Compression index C r = Recompression index DFS = Differential Free swell G = Specific gravity LL = Liquid limit (%) OMC = Optimum moisture content (%) PL = Plastic limit (%) PI = Plasticity index (%) SL = Shrinkage limit (%) f = Angle of internal friction ( o ) Declarations Conflicts of interest/Competing interests The authors have no conflicts of interest to declare that are relevant to the content of this article. Funding The authors declare they have no financial interests. No funding was received to assist with the preparation of this manuscript. Author Contribution Guruprasad Chavan collected samples, performed testing, prepared figures and tables. Chavan and Savoikar wrote the manuscript and was reviewed by Savoikar. Availability of data and material Not applicable Code availability Not applicable References Pashabavandpouri, M.A., Goodarzi, A.R. and Lajevardi, S.H.: Enhancing the Mechanical and Microstructural Properties of Expansive Soils using Industrial Waste, Nano-material and Polypropylene Fibres: A Comparative Study. International Journal of Geosynthetics and Ground Engineering. 9, 54 https://doi.org/10.1007/s40891-023-00467-6. (2023). Kumar, A., Walia, B. S., and Bajaj, A.: Influence of fly ash, lime, and polyester fibres on compaction and strength properties of expansive soil”, Journal of Materials in Civil Engineering, ASCE, Vol. 19, No.3. doi:10.1061/(asce)0899-1561(2007)19:3(242) (2007). Nayak N. V.: Foundation design manual. Dhanpat Rai Publications, seventh edition, ISBN: 978-93-83182-90-9 (2015). IS 2911-3: Code of practice for design and construction of pile foundations, Part 3: Under-reamed piles (1980). Holtz, W. and Gibbs, H.: Triaxial Shear Tests on Pervious Gravelly Soils. J. Soil Mech. and Found. Div.. 82. 1-22. 10.1061/JSFEAQ.0000004 (1956).. Sivakumar Babu, G. L., Vasudevan, A. K., and Sayida, M. K.: Use of Coir Fibres for Improving the Engineering Properties of Expansive Soils. Journal of Natural Fibres, 5(1), 61–75. doi:10.1080/15440470801901522 (2008). Tang, Y. H., Bao, C. G., Wang, M. Y., and Ding, J. H.: Experimental Study on the Strength Characteristics of Expansive Soil Reinforced With Synthetic Fibres. Geosynthetics in Civil and Environmental Engineering, 369–373. doi:10.1007/978-3-540-69313-0_71 (2008). Elayaraja, S. and Arumairaj, P. D.: Study on the shear strength of black cotton soil reinforced with geosynthetics, National Conference on Advances in Steel Concrete and Composite Structures, Department of Civil Engineering, Government College of Technology, Coimbatore-13, Vol.1 (2009). Babu, G. L. S., and Chouksey, S. K.: Model for analysis of fibre-reinforced clayey soil. Geomechanics and Geoengineering, 5(4), 277–285. doi:10.1080/17486021003706804 (2010). . Srivastava, A., Pandey, S., and Rana, J.: Use of shredded tyre waste in improving the geotechnical properties of expansive black cotton soil. Geomechanics and Geoengineering, 9(4), 303–311. doi:10.1080/17486025.2014.902121 (2014). Ashango, A. A., and Patra, N. R.: Behaviour of Expansive Soil Treated with Steel Slag, Rice Husk Ash, and Lime. Journal of Materials in Civil Engineering, 28(7), 06016008. doi:10.1061/(asce)mt.1943-5533.0001547 (2016). Gobinath, R., Ganapathy, G. P., Akinwumi, I. I., Kovendiran, S., Hema, S., and Thangaraj, M.: Plasticity, strength, permeability and compressibility characteristics of black cotton soil stabilized with precipitated silica. Journal of Central South University, 23(10), 2688–2694. doi:10.1007/s11771-016-3330-7 (2016). . Dalal, S. P., Patel, R., and Dalal, P. D.: Effect on Engineering Properties of Black Cotton Soil treated with Agricultural and Industrial Waste. Materials Today: Proceedings, 4(9), 9640–9644. doi:10.1016/j.matpr.2017.06.240 (2017). Etim, R. K., Eberemu, A. O., and Osinubi, K. J.: Stabilization of black cotton soil with lime and iron ore tailings admixture. Transportation Geotechnics, 10, 85–95. doi:10.1016/j.trgeo.2017.01.002 (2017). Uppal, H. L., and Chadda, L. R.: Physico-chemical changes in the lime stabilization of black cotton soil (India). Engineering Geology, 2(3), 179–189. doi:10.1016/0013-7952(67) 90017-8 (1967). Raychaudhuri, S. P., Roy, B. B., Gupta, S. P. and Dewan, M. L.: Black soils of India. Nat. Inst. Sci. India, 47 (1963). Wild, S., Kinuthia, J. M., Robinson, R. B., and Humphreys, I.: Effects of ground granulated blast furnace slag (GGBS) on the strength and swelling properties of lime-stabilized kaolinite in the presence of sulphates. Clay Minerals, 31(03), 423–433. doi:10.1180/claymin.1996.031.3.12 (1996). Al-Taie, A., Disfani, M., Evans, R., Arulrajah, A., and Horpibulsuk, S.: Volumetric Behavior and Soil Water Characteristic Curve of Untreated and Lime-Stabilized Reactive Clay. International Journal of Geomechanics, 19(2), 04018192. doi:10.1061/(asce)gm.1943-5622.0001336 (2019). Oza, J. B., and Gundaliya, P. J.: Study of Black Cotton Soil Characteristics with Cement Waste Dust and Lime. Proceedia Engineering, 51, 110–118. doi:10.1016/j.proeng.2013.01.017 (2013). Das, A. and Soni, D. K.: Effect of the ground granulated blast furnace slag (GGBS) and lime mix on the hydraulic conductivity of expansive clay. International Conference on Recent Trends and Challenges in Civil Engineering December 12-14, MNNIT Allahabad, India (2014). Yi, Y., Gu, L., Liu, S., and Puppala, A. J.: Carbide slag–activated ground granulated blastfurnace slag for soft clay stabilization. Canadian Geotechnical Journal, 52(5), 656–663. doi:10.1139/cgj-2014-0007 (2015). Saride, S., and Dutta, T. T.: Effect of Fly-Ash Stabilization on Stiffness Modulus Degradation of Expansive Clays. Journal of Materials in Civil Engineering, 28(12), 04016166. doi:10.1061/(asce)mt.1943-5533.0001678 (2016). Verma, H., Ray, A., Rai, R., Gupta, T., and Mehta, N.: Ground improvement using chemical methods: A review. Heliyon, 7(7), e07678. doi:10.1016/j.heliyon.2021.e07678 (2021). Chang, I., Im, J., Prasidhi, A. K., and Cho, G. C.: Effects of Xanthan gum biopolymer on soil strengthening. Construction and Building Materials, 74, 65–72. doi:10.1016/j.conbuildmat.2014.1 (2015). Soldo, A., and Miletić, M.: Study on Shear Strength of Xanthan Gum-Amended Soil. Sustainability, 11(21), 6142. doi:10.3390/su11216142 (2019). Begum, A. S., Prasada Raju, G. V. R., Prasad, D. S. V., and Anjan Kumar, M.: Influence of Terrazyme on compaction and consolidation properties of expansive soil. In Problematic Soils and Geoenvironmental Concerns: Proceedings of IGC 2018 (pp. 525-535). Singapore: Springer Singapore (2020). Chavan, G.A. and Savoikar, P.: Characterization of Black Cotton Soil in Kolhapur Region. Indian Geotechnical Journal. 53, 1454–1467. https://doi.org/10.1007/s40098-023-00766-9 (2023). Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7142521","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":502005822,"identity":"b1c4857f-34d0-47a0-87dd-e05171ea76d1","order_by":0,"name":"Guruprasad Ajay Chavan","email":"","orcid":"","institution":"Goa Engineering College (affiliated to Goa University)","correspondingAuthor":false,"prefix":"","firstName":"Guruprasad","middleName":"Ajay","lastName":"Chavan","suffix":""},{"id":502005824,"identity":"59fb2c87-784d-4f27-adfe-4ed2d8945b3d","order_by":1,"name":"Purnanand P Savoikar","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAApklEQVRIiWNgGAWjYHACxgcw1gFitTAbkKyFTYJYlRBgLt3+rPJLhR0Df/sBxsMFxGixnHPG7LbMmWQGiTMJDIdnEKPF4EYO223JtgMMDDcYGA7zEKcl/Vmx5L8DDPIkaEkwY/zYcADIIFYL0C/G0gzHknkMzyQ2EKcFGGIPP/6osZOTO3748GfiHAaMFGagSiBibCBGA0QL4w/i1I6CUTAKRsFIBQBZPDD9fylDhQAAAABJRU5ErkJggg==","orcid":"","institution":"Goa Engineering College (affiliated to Goa University)","correspondingAuthor":true,"prefix":"","firstName":"Purnanand","middleName":"P","lastName":"Savoikar","suffix":""}],"badges":[],"createdAt":"2025-07-16 17:53:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7142521/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7142521/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":89412197,"identity":"b0b47aa5-84b1-4d31-8280-2ec906008314","added_by":"auto","created_at":"2025-08-19 16:28:53","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":81577,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe percentage of expansive soils on land covered in some countries [1].\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/93fef63f4e68ff0073dcd4a1.png"},{"id":89412668,"identity":"925e67c5-8b05-4bc7-b885-495bce7b22d6","added_by":"auto","created_at":"2025-08-19 16:36:53","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":431568,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(a) SEM images of 30% GGBS stabilized clay at high magnification (×5000) after 7 days, and (b) SEM images of the same clay at high magnification (×5000) after 90 days, showing a C/G ratio of 0.40. \u003c/strong\u003e(Yi et al. [21])\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/00e0bcc8122a9e12453cd322.png"},{"id":89412190,"identity":"9548cb18-59ba-4c4c-9d01-3e2dfc707d58","added_by":"auto","created_at":"2025-08-19 16:28:53","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":334184,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSEM images of Xanthan gum biopolymer treated clay (\u003c/strong\u003eChang et al. [24])\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/fd35a1cdc1de8e5bce226d6b.png"},{"id":89412192,"identity":"56925cdb-4451-4b9c-a2c6-491b81c8f6f4","added_by":"auto","created_at":"2025-08-19 16:28:53","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":277187,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSampling locations in study area\u003c/strong\u003e (adapted from https://www.diva-gis.org)\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/cf487904812fd10b18d5e85e.png"},{"id":89412195,"identity":"30cee0f8-aaba-4d84-8e2d-ac5aa6d54440","added_by":"auto","created_at":"2025-08-19 16:28:53","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":22300,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eConsistency of BC soil with Terrazyme\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/9a9c4ce0475652dc4eeea820.png"},{"id":89413469,"identity":"a6851036-085b-4d52-b126-22a47dfcb643","added_by":"auto","created_at":"2025-08-19 16:44:53","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":19216,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePlasticity index of BC soil with Terrazyme\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/011fa5189564a2c3f96cc813.png"},{"id":89413471,"identity":"8ab99170-c225-4787-99b3-732481f2f3b4","added_by":"auto","created_at":"2025-08-19 16:44:53","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":23129,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMaximum dry density with Terrazyme\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/7a3f5314f08d9138ff1970e0.png"},{"id":89412671,"identity":"44331047-b4f6-486e-91c2-954f26e3a3a9","added_by":"auto","created_at":"2025-08-19 16:36:53","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":20272,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eOptimum moisture content with Terrazyme\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/e34308401baca562fe54745f.png"},{"id":89412676,"identity":"92ad8094-5930-41cd-ab55-462d90f0ddad","added_by":"auto","created_at":"2025-08-19 16:36:53","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":22637,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eCalifornia bearing ratio value with Terrazyme\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/43b21d77084d2ea7633fdfef.png"},{"id":89412680,"identity":"3212e2ad-ff61-4130-a250-f09fc518311e","added_by":"auto","created_at":"2025-08-19 16:36:53","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":23394,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eUnconfined compression strength with Terrazyme\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/4b714e2016810740eefb1c07.png"},{"id":89412204,"identity":"13c4d38d-66b0-4b97-b0df-cb38c8f503d6","added_by":"auto","created_at":"2025-08-19 16:28:53","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":23950,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMaximum dry density with Xanthan gum\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/c41a221e778431dcb633e6b8.png"},{"id":89412210,"identity":"ce9624b9-9070-40b9-906c-623b294a0711","added_by":"auto","created_at":"2025-08-19 16:28:53","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":16703,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eOptimum moisture content with Xanthan gum\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/633687605d994a06a0f2a162.png"},{"id":89412206,"identity":"4e965a49-4d59-4de3-a029-ed78b733f5e2","added_by":"auto","created_at":"2025-08-19 16:28:53","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":19852,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eCalifornia bearing ratio value with Xanthan gum\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"13.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/02a418dd670fbf33bb5c22ba.png"},{"id":89412208,"identity":"4a6aa4ff-300f-4f90-9272-dd7391796ccd","added_by":"auto","created_at":"2025-08-19 16:28:53","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":22394,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eUnconfined compression strength with Xanthan gum\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"14.png","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/8999927d998f72db5ee99c8e.png"},{"id":91329104,"identity":"6f1c520b-a498-498a-b437-51d5bde20906","added_by":"auto","created_at":"2025-09-15 10:32:23","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3368620,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7142521/v1/b2ab1822-424b-4a01-954b-71decb9b4cbb.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Use of Bio-enzymes and Natural Adhesives for Improvement of Geotechnical Properties of Black Cotton Soils","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eExpansive soil, such as black cotton soil, behaves differently depending on the proportion of different minerals present. Black cotton soil's high clay content causes it to shrink and swell in response to moisture changes, resulting in cracks and damage to structures built on it. To address this issue, various techniques such as soil stabilization and proper drainage systems are used during construction. Globally, expansive soils are present; in certain countries, the proportion of land covered by these soils is displayed in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eExpansive soils, also known as black cotton soils, expand when moisture levels rise, owing primarily to the clay mineral montmorillonite. These soils, predominantly black and abundant in cotton cultivation, are found in states like Maharashtra, Gujarat, Uttar Pradesh, Rajasthan, Madhya Pradesh, Andhra Pradesh, and Chennai. They cover over 0.8 x \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{10}^{6}\\text{s}\\text{q}.\\text{k}\\text{m}\\)\u003c/span\u003e\u003c/span\u003e, or over one-fifth of the nation [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The colour of black cotton soil ranges from reddish brown to black. They are found at depths of 0.50 to 10 meters and have a high compressibility. The typical characteristics of the soil are listed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eTypical characteristics of Black cotton soil (Nayak, 2015 [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e])\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eProperty\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eValue\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eGrain size distribution\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eGravel\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0 to 10%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSand\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15 to 25%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSilt\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15 to 30%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eClay\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e25 to 70%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eConsistency limits\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLiquid limit\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50 to 120%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePlastic limit\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30 to 60%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePlasticity index\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e20 to 60%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eShrinkage limit\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8 to 18%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSoil Classification\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCI or CH or MH\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSpecific gravity\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2.60\u0026ndash;2.75\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003epH value\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8 to 10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eOrganic content\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.4 to 2.4%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDifferential free swell (DFS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e40\u0026ndash;180%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSwelling pressure\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50\u0026ndash;800 kN/m\u0026sup2;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eAs per IS:2911 (Part III)-1980 [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] Annexure - A and Holtz and Gibbs [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], black cotton soils are classified as having low degree of expansiveness (DFS less than 20), moderate expansiveness (DFS between 20 to 35), high expansiveness expansiveness (DFS between 35 to 50) and very high expansiveness (DFS greater than 50). This indicates that as per Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, these soils can be classified as soils with moderate to very high expansiveness.\u003c/p\u003e\u003cp\u003eBlack cotton soil is considered critical soil from the point of view of construction on it. Hence, analysis and improvement of soil are necessary and also requirements of the construction field. Many researchers have studied black cotton soil in the past and evaluated it with different stabilization techniques. Lime stabilization, cement stabilization, and chemical stabilization are examples of these techniques. The process of adding lime to soil to improve its properties such as increasing strength and reducing plasticity is known as lime stabilization. Cement stabilization, is mixing cement with soil to increase compressive strength while decreasing expansiveness. Finally, chemical stabilization entails the application of different chemicals to change the qualities of the soil and make it appropriate for building. These stabilizing procedures have been shown to be helpful in reducing the probable damages caused by black cotton soil and assuring the stability and durability of various civil engineering structures erected on it.\u003c/p\u003e"},{"header":"2. Literature Review","content":"\u003cp\u003eIn the present study, a detailed review of literature on stabilization of black cotton soils using conventional stabilizers, fibres, agricultural and industrial waste, chemical stabilizers, natural adhesives and bioenzymes is undertaken.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Black cotton soil Stabilization by Conventional Stabilizers, Fibres, Agricultural and Industrial Waste\u003c/h2\u003e\u003cp\u003eKumar et al. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] found that increasing lime content reduces the maximum dry density of soil-lime mixes while increasing moisture content increases. When fly ash is added to soil-lime mixtures, the maximum dry density decreases while moisture content increases. The strength of fly ash-soil-lime-fibre mixtures increases with the percentage of fly ash while the lime content remains constant. The recommended lime content and fly ash content are 8 and 15%, respectively. Fibres increase both unconfined compressive strength and split tensile strength. Babu et al. [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] a study in Davangere district, Karnataka, used tri-axial shear tests, swelling tests, and consolidation tests to evaluate the strength, swelling, and compressibility of black cotton soil reinforced with coir fibres. The results showed that using coir as a random reinforcing material can improve engineering behavior and coir fibres reduced the swell potential of black cotton soil and reduced the compression index due to fibre inclusion. In Xinxiang, China, Tang et al. [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] investigated the behavior of expansive soil reinforced with synthetic polypropylene monofilament fibres. It was reported that the increased fibre concentration causes the stress-strain curve to shift from a strain-softening to a strain-hardening type, and soil reinforced with fibres has an undrained strength that is sensitive to water content, increasing by 105% when the water content is lowered. Elayaraja and Arumairaj [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] analyzed black cotton soil from Coimbatore, India, using two methodologies to evaluate the strength behavior geosynthetics reinforced soil. It was observed that the introduction of non-woven geotextiles increased the shear strength of black cotton soil, making it suitable for drainage, filtration, fine particle separation, embankment geomembrane, and the structures like flyovers. Clayey soil specimens reinforced with discrete coir fibres were investigated by Babu and Chouksey [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], who also carried out numerical simulations of triaxial compression tests on clay specimens reinforced with fibres. It was shown that adding fibres to the soil strengthens its ability to respond to stress and strain in clayey soils. Srivastava et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] found that adding 30\u0026ndash;50% shredded tire waste to black cotton soil reduced its volume change potential and shear strength, suggesting it can be used as a backfill material in mixing, walls to lower backfill pressure and minimize swelling and shrinking.\u003c/p\u003e\u003cp\u003eExpansive soil from the Banda district in Uttar Pradesh, India was examined by Ashango et al. [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] and stabilized with steel slag, rice husk ash, and quick lime. The optimum mix of these elements was found to be expansive soil, steel slag, rice husk ash, and quick lime at 65, 20, 5, and 10%, respectively. The soil plasticity decreased to 66.2%, while its strength increased to 96%. The mixture was shown to be as durable as the sub-grade material, with its dynamic characteristics increasing soil stiffness by 58\u0026ndash;78%. Gobinath et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] explored the use of precipitated silica (PS) from rice husk to enhance the geotechnical engineering properties of black cotton soil. The optimal PS content of 50% is recommended for improving the sub-grade characteristics of the soil for pavement layer use. Dalal et al. [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] used agricultural and industrial waste to stabilize black cotton soil using a combination of bagasse ash, ground granulated blast furnace slag (GGBS), and wood powder. Wood powder effectively controlled swelling in the soil, up to 58%. Bagasse ash and GGBS improved the strength of the soil sample, with GGBS and bagasse ash contributing more to strength and wood powder for swelling control. Etim et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] investigated the stabilization of black cotton soil in Gombe State, Nigeria, utilizing up to 8% lime with up to 10% iron ore tailing (IOT). The study also examined the leaching potential of iron from the soil-lime-IOT mixes, indicating its usefulness as a sub-base material for light trafficked roads.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Chemical Stabilization of Black Cotton Soil\u003c/h2\u003e\u003cp\u003eUppal and Chadda [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] examined the chemical and physical alterations that occur when lime is used to stabilize Indian black cotton soils. It was discovered that clay particles smaller than 0.002 mm aggregate into larger particles (0.02\u0026ndash;0.05 mm). With low lime concentration, this behavior is closely related to the aggregation of calcium hydroxide and other alkaline earth metals. Raychaudhuri et al. [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] presented generalized characteristics, and chemical analysis results of black cotton soils in India, as illustrated in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e\u003cb\u003eCharacteristics with chemical analysis of Indian black cotton soil (\u003c/b\u003eRaychaudhuri et al. 1963 [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eProperties\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eRange of values\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eClay and silt fraction\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e70\u0026ndash;80%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCourse sand\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4\u0026ndash;8%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003epH\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7.2\u0026ndash;8.5%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTotal solids\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.05\u0026ndash;1.5%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSalt concentration depth\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5\u0026ndash;7 ft.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAcid solubles\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1\u0026ndash;10%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCation exchange capacity (CEC)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e40\u0026ndash;60 meq /100 g\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eExchange calcium\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15\u0026ndash;42%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eExchange magnesium\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6\u0026ndash;20%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eExchange K₂O\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.1\u0026ndash;0.6%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eExchange sodium\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3\u0026ndash;13%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFe₂O₃\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9\u0026ndash;13%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eA1₂O₃\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16\u0026ndash;23%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eR₂O₃\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e25\u0026ndash;36%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCaO\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2.5-7%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMgO\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3\u0026ndash;4%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSiO₂\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50\u0026ndash;55%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eWild et al. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] reported that Kaolinite clay with gypsum and lime exhibits high expansion when cured, but adding (GGBS) reduces this expansion and increases compressive strength. Adjusting the lime-GGBS ratio can modify both properties. The reduction in expansion is due to a balance between competing hydration reactions, which inhibits ettringite nucleation. Further research is needed to confirm this hypothesis using a wider range of compositions and micro-analytical methods. Asmaa et al. [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] examined the impact of lime stabilization on expansive clay in Victoria, Australia. The soil was treated with an optimum lime content (OLC) that reduced swell potential, and the soil-water characteristic curve (SWCC) was used to analyze the soil behavior. The soil specimens were tested under various stress levels and moisture ratios. The results showed that the soil was highly collapsible under higher suction pressures and less compaction stress. Additionally, significant swelling occurred under higher suction pressures and higher compaction stress. The study concluded that although the soil was treated with lime at the OLC, it was not highly collapsible under different stress levels. Oza and Gundaliya [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] improved the behavior of Rajkot region BC soil using three additives, with cement dust providing substantial and durable benefits as a stabilizing agent. The summary of the optimum dosage of three additives and their effect on plasticity and increment in compressive strength is presented as per Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e\u003cb\u003eBlack cotton soil with identified optimum dosage of additive (\u003c/b\u003eOza and Gundaliya [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e])\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eType of Stabilizing agent\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eOptimum Percentage used in BC Soil\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePlasticity Index\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCuring period for Compressive Strength (Days)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eCompressive Strength (N/\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\mathbf{m}\\mathbf{m}}^{2}\\)\u003c/span\u003e\u003c/span\u003e )\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCement Dust\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e11.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e17.47\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCement Dust\u0026thinsp;+\u0026thinsp;Lime\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e9.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e14.46\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLime\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e8.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e10.91\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eDas and Soni [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] investigated the effects of GGBS and lime on the hydraulic conductivity of expansive clay minerals such as kaolinite, montmorillonite, and illite clay. A study revealed that adding lime and GGBS reduces kaolinite's permeability, increasing hydraulic conductivity as time elapses. However, kaolinite's conductivity decreases due to GGBS and lime, possibly due to calcium silicate hydrate gel formation or decreased inter-aggregate pore size. Yi et al. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] investigated the usage of carbide slag (CS) and ground granulated blast furnace slag (GGBS) to stabilize soft clay and compared it to Portland cement (PC). Scanning electron microscopy (SEM) micrographs (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) of 30% GGBS stabilized clays with carbide slag/ground granulated blast furnace slag (C/G) ratios of 0.15 and 0.40 at 7 and 90 days revealed limited hydration and irregularly shaped calcium silicate hydrates (CSH) and cubical shaped calcium aluminate hydrates (CAH).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eSaride and Dutta [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] investigated the stabilization of expansive soils using class C fly ash to improve swelling, stiffness, and damping properties. It was reported that the normalized modulus degradation decreased with increased confining pressure and fly ash content, and the Poisson's ratio decreased with increased confining pressure and fly content. Verma et al. [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] chemical stabilization methods were categorized into four main subgroups as biochemical, electrochemical, inorganic pozzolanic/cementitious material, and organic polymeric binders, based on nature and chemical composition. Different methods were discussed by many researches for improvement of black cotton soil also assessed with various laboratory tests with changes in microstructure. These analyses are helpful for field applications as well as for further research.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Improvement of Black Cotton Soil by Natural Adhesives and Bio-Enzymes\u003c/h2\u003e\u003cp\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eChang et al. [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] found that Xanthan gum, a polysaccharide used as a food additive and rheology modifier, can significantly increase soil compressive strength when used with fine-grained soil. Xanthan gum bridges between distant particles, enhancing particle alignment and strength improvement, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The most economical and efficient concentration for soil treatment is approximately 1\u0026ndash;1.5%. Xanthan gum is recommended for soil improvement, especially for dry soil, with minimal adverse effects.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eSoldo and Miletic [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] investigated the impact of Xanthan gum on soil engineering properties using three mechanical tests as unconfined compression, unconsolidated undrained triaxial, and direct shear. Results showed that Xanthan gum improved the strength of all soil types, with the highest strength achieved for silty sand. The study also found that Xanthan gum increased cohesion in cohesionless soils but not friction angles. Begum et al. [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] discussed the use of Terrazyme, a universally available bioenzyme, for soil augmentation and stabilization. Laboratory tests showed that Terrazyme reduces clay content, increases coarser particles, decreases liquid and plastic limits, and increases maximum dry density. It also reduces the compressive index and coefficient of compressibility, making it a cost-effective solution for expansive soil intensification.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Critical appraisal of the literature\u003c/h2\u003e\u003cp\u003eThe above used industrial waste, agricultural waste recovered materials, and other cementation materials using readily available stabilizing agents. Ground improvement alters soil properties, allowing for a variety of building processes. Shear strength, swelling and shrinkage properties, and bearing capacity are examples of these qualities. These strategies are increasingly being used in the building business where the soils have poor subsurface characteristics. The use of different fibres and agricultural by-products as soil amendments can enhance its strength and stability. Furthermore, the incorporation of natural adhesives, chemical stabilizers, and bio-enzymes can help alleviate issues such as shrinkage and swelling, ultimately making the soil more suitable for construction purposes. By examining the changes in microstructure through laboratory assays, this research provides valuable insights into the mechanisms behind soil improvement, which can inform future studies and guide the development of more efficient techniques and machinery for soil stabilization. Very less research work on improvement of black cotton soils using bioenzymes or biopolymers using curing is available.\u003c/p\u003e\u003cp\u003eIn the present study, a detailed experimental programme is undertaken to investigate effect of natural adhesive and bio-enzymes such as Xanthan gum and Terrazyme on geotechnical properties of black cotton soils in Kolhapur region.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Experimental programme","content":"\u003cp\u003eSoil stabilization strategies are mostly determined by the nature of the stratum and the goal of development. Additives including lime, bitumen, fly ash, cement, and others are used on the site to enhance the characteristics of the soil. The study aims to improve black cotton soil in Kolhapur, Maharashtra, India, using natural adhesives Xanthan gum and bio-enzyme Terrazyme. Samples were collected from various regions of the city, and properties were analyzed at different depths. The study aims to address the expansion of the city limits and improve the soil's quality for future use. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows the location of the study area and all sampling locations [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Geotechnical properties of Kolhapur black cotton soils\u003c/h2\u003e\u003cp\u003eSampling was done at twenty eight different locations. Samples were collected from different depths below ground level as 0.5m, 1m, 1.5m, 2m, 2.5m 3.0m, 3.5m and at 4.0m.Various tests were conducted on samples collected as per the relevant Indian Standards and results were analyzed, soil Characteristics are listed in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e (Chavan and Savoikar [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]). Classification of soil was done on the basis of plasticity chart with the help of soil test results.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e\u003cb\u003eCharacteristics of black cotton soil in study area\u003c/b\u003e (Chavan and Savoikar [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e])\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSoil property\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eRange of values\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003e\u003cb\u003eMechanical analysis\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSand\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15 to 30%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSilt and Clay\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e60 to 95%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003e\u003cb\u003eConsistency limits\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLiquid limit (LL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e38.46\u0026ndash;65.40%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePlastic limit (PL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e22.0\u0026ndash;51.71%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePlasticity index(PI)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11.89-30%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eShrinkage limit (SL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9.15\u0026ndash;16%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSoil classification\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCH-MH-CI\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSpecific gravity(G)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2.08\u0026ndash;2.73\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eField density\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13.8-19.8kN/m\u0026sup3;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDry density\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10.45\u0026ndash;14.80 kN/m\u0026sup3;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eProctor density\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13.5\u0026ndash;17.2 kN/m\u0026sup3;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eOptimum moisture content (OMC)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13.50\u0026ndash;20.90%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDifferential Free swell (DFS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e20\u0026ndash;60%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCalifornia bearing ratio (CBR unsoaked)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2.4\u0026ndash;4.60%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCohesion (c)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e19.61\u0026ndash;37.27 kN/m\u0026sup2;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAngle of internal friction (φ)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8.75\u0026ndash;24.32\u0026deg;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUnconfined compression strength\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e62.22\u0026ndash;68.95 kN/m\u0026sup2;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCompression index (C\u003csub\u003ec\u003c/sub\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.454\u0026ndash;0.499\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRecompression index (C\u003csub\u003er\u003c/sub\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.030\u0026ndash;0.033\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe above soil samples were collected from 28 locations at three different sites. Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e shows the variation in differential free swell and expansiveness classification at these locations.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDifferential free swell and expansiveness classification of soils in Kolhapur\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLocation\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eDifferential Free Swell\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003eExpansiveness\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRankala\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30 to 60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eModerate to very high\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLine Bazar\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e40 to 60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHigh to very high\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRamnagar\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e40 to 50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHigh\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eKarande Mala, Tarabai Park\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e18 to 20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLow\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSugar Mill, Bawada\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e20 to 40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eModerate to high\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBiranje Panand, Bawada\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30 to 50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eModerate to high\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eChambukhadi, Phulewadi\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHigh\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRamnagar, near Dasara Chowk\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHigh\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e9.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eKandalgaon\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHigh\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e10.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRankala\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e11.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eKaneriwadi\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHigh\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e12.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eShiroli\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e13.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eVathar\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c5\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Improvement using bio-enzymes\u003c/h2\u003e\u003cp\u003eTerrazyme is a non-toxic, natural liquid bio-enzyme mixture that changes the physical and chemical properties of soil. When Terrazyme is introduced in to the soil, it catalyzes the decomposition of organic molecules and enhances the soil particles' wetting and bonding ability. It enables soil materials to be wetter and more tightly compacted. Furthermore, better chemical bonding aids in the fusion of soil particles, resulting in a more permanent structure that is more resistant to weathering, abrasion, and water penetration. Some Terrazyme characteristics are mentioned in Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e below, as provided by the supplier.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e\u003cb\u003eCharacteristics of Terrazyme\u003c/b\u003e (supplied by manufacturer)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eIdentity\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTerrazyme\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHazardous Components\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNone\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBoiling point\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e212F\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSpecific Gravity\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.05\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMelting point\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eLiquid\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eEvaporation rate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSame as water\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSolubility in water\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eComplete\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAppearance/Odor\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eBrown liquid, non-obnoxious\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eConditions to avoid\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;45\u0026deg;C ; pH below 3.5, above 9.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eIncompatibility\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCaustics, strong bases\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eStoring\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003etemperature below 45\u0026deg;C\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Results and discussions","content":"\u003cp\u003eThe improvement in geotechnical properties of black cotton soil such as consistency limits, maximum dry density and optimum moisture content, unconfined compression strength and California bearing ratio has been evaluated by varying the dosage of Terrazyme and Xanthan gum is evaluated. The results are presented below:\u003c/p\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e4.2. Terrazyme as bio-enzyme type stabilizer\u003c/h2\u003e\u003cp\u003eThe tests conducted were specific gravity, plastic limit, liquid limit, standard proctor test, California bearing ratio value (CBR), and unconfined compression test. Sampling was done up to a depth of 4.0 m in 4 different layers; hence, soil from 4.0m below ground level was mixed with Terrazyme. Soil was treated with different dosages i.e. 0.5 ml per 100 ml of water, 1.0 ml per 100 ml of water, 1.5 ml per 100 ml of water, 2.0 ml per 100 ml of water and 2.5 ml per 100 ml of water, and subjected to various tests.\u003c/p\u003e\u003cp\u003eCuring is helpful in UCS and CBR testing as regards the strength development, simulating the field conditions and for obtaining consistent and reliable data. Proper curing allows for the full development of the soil's strength, particularly in stabilized soils where chemical reactions contribute to strength gain.\u003c/p\u003e\u003cp\u003eBefore curing, the soil sample is typically compacted to the desired density using a mould and compaction tool. The moisture content is adjusted to achieve the optimal compaction, often based on the Proctor test results. After compaction, the sample is carefully extracted from the mould and trimmed to the standard dimensions required for the UCS test, typically maintaining a height-to-diameter ratio of 2:1. For the UCS test on a saturated or near-saturated soil sample, the curing process involves maintaining the sample in a moist environment. This can be done by wrapping the sample in plastic film or placing it in a sealed container to prevent moisture loss. When soil samples are treated with stabilizers curing can last from 7 days to several months. This longer curing period allows chemical reactions to occur, significantly increasing the strength of the sample.\u003c/p\u003e\u003cdiv id=\"Sec12\" class=\"Section3\"\u003e\u003ch2\u003e4.1.1 Influence of Terrazyme on consistency limits of black cotton soil\u003c/h2\u003e\u003cp\u003eEffect of Terrazyme on consistency of soil was analyzed and results were tabulated in Table\u0026nbsp;\u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e. Also, Figs.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e and \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e show variation of consistency limits with different dosages of Terrazyme. It was observed that consistency limits decreased with addition of Terrazyme. Liquid limit decreased by 22.51%, plastic limit by 19.62% and the plasticity index by 39.35%.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab7\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffect of Terrazyme on consistency limits of black cotton soil\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDosage (ml)/100 ml of water\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eLiquid Limit (LL) %\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePlastic Limit (PL) %\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePlasticity Index (PI) %\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUntreated\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e62.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e45.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e17\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e54.37\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e40.12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e14.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e50.51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e36.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e14.18\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e48.53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e38.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10.31\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e48.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e37.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10.75\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e48.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e37.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10.77\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section3\"\u003e\u003ch2\u003e4.1.2 Influence of Terrazyme on maximum dry density and optimum moisture content\u003c/h2\u003e\u003cp\u003eEffect of Terrazyme on maximum dry density and optimum moisture content is presented in Table\u0026nbsp;\u003cspan refid=\"Tab8\" class=\"InternalRef\"\u003e8\u003c/span\u003e and Figs.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e and \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e. It is observed that about 11.83% increase in maximum dry density and marginal decrease in OMC was observed. This is due to increased adhesion between particles and resulting densification of soil after addition of Terrazyme.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab8\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffect of Terrazyme on maximum dry density\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDosage(ml)/ 100 ml of water\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMaximum Dry Density (MDD ) kN/ m\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOptimum Moisture Content (OMC)\u003c/p\u003e\u003cp\u003e%\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUntreated\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e16.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e13.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e17.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.50\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e17.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e18.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e18.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.50\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e18.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.50\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section3\"\u003e\u003ch2\u003e\u003cb\u003e4.1.3 Influence of Terrazyme on California bearing ratio value of black cotton soil\u003c/b\u003e\u003c/h2\u003e\u003cp\u003eEffect of Terrazyme on California bearing ratio value (CBR) was analyzed and results were tabulated in Table\u0026nbsp;\u003cspan refid=\"Tab9\" class=\"InternalRef\"\u003e9\u003c/span\u003e. Also, Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e shows variation of California bearing ratio value with different dosage of Terrazyme with curing period. After seven days of curing with Terrazyme dosage of 1.5 ml per 100 ml of water, the California bearing ratio value increased by 76.32%.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab9\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 9\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffect of Terrazyme on CBR value\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDosage(ml)/ 100 ml of water\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003eCalifornia bearing ratio value (CBR) %\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eCuring period (days)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e07\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUntreated\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3.80\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e4.59\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.44\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e5.10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e6.70\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.62\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e6.10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e5.60\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec15\" class=\"Section3\"\u003e\u003ch2\u003e\u003cb\u003e4.1.4 Influence of Terrazyme on Unconfined compression strength (UCS) of black cotton soil\u003c/b\u003e\u003c/h2\u003e\u003cp\u003eThe effect of Terrazyme on the unconfined compression strength value was investigated, and the findings are shown in Table\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e10\u003c/span\u003e. Figure\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e also depicts the fluctuation of unconfined compression strength with different Terrazyme dosages. It is observed that the unconfined compression strength increased by 57.89% with Terrazyme dosage of 1.5 ml per 100 ml of water after 7 days of curing. It was found that the optimum Terrazyme dose for stabilizing black cotton soil is 1.5 ml per 100 ml of water. It is observed that addition of Terrazyme results in increase of soil strength, more prominently after 7 days of curing.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab10\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 10\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffect of Terrazyme on unconfined compression strength on curing\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDosage(ml)/ 100 ml of water\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003eUnconfined compression strength (UCS) kN/m\u0026sup2;\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eCuring period (days)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e07\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUntreated\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e64.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e71.12\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e82.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e86.30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e86.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e90.71\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e89.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e112.22\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e87.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e110.18\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e80.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e104.30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003e4.2 Xanthan gum as natural adhesives\u003c/h2\u003e\u003cp\u003eXanthan gum is a polysaccharide produced by the \u003cem\u003exanthomonas campestris\u003c/em\u003e bacterium and used as a food additive and rheology modifier. It is composed of D-uronic acid, D-mannose, pyruvylated mannose, 6-O-acetyl D-mannose, and 1,4-linked glucan. Its pseudo-plasticity and high stability under various temperatures and pH make it a popular choice in food. Xanthan gum is also used in the oil industry as a drilling mud thickener and in concrete to increase viscosity and prevent washouts [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Xanthan gum, a hydrophilic polymer with a high molecular weight, is produced by the fermentation of carbohydrates in \u003cem\u003exanthomonas campestris\u003c/em\u003e.\u003c/p\u003e\u003cp\u003eBlack cotton soil was treated with different dosages of Xanthan gum i.e. 0.2%, 0.4%, 0.6%, 1.0%, 1.5% and 2.0% of soil. The soil which was treated with Terrazyme, the same soil is used for Xanthan gum treatment also. Effect of Xanthan gum on soil was analyzed on the basis of different laboratory tests such as standard proctor test, California bearing ratio value (CBR), and unconfined compression test (UCS).\u003c/p\u003e\u003cp\u003e\u003cb\u003e4.2.1 Influence of Xanthan gum on maximum dry density and optimum moisture content of black cotton soil\u003c/b\u003e\u003c/p\u003e\u003cp\u003eStandard Proctor tests were conducted on black cotton soil. Effect of Xanthan gum on maximum density of soil is tabulated in Table\u0026nbsp;\u003cspan refid=\"Tab11\" class=\"InternalRef\"\u003e11\u003c/span\u003e. Also, Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e shows variation of maximum density with different dosage of Xanthan gum and Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e shows variation of moisture content. There is about 13.61% increase in maximum dry density after 1.5% dosage of Xanthan gum with marginal reduction in OMC values.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab11\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 11\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffect of Xanthan gum on maximum dry density and optimum moisture content\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDosage (%) of weight of soil sample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMaximum Dry Density (MDD ) kN/ m\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOptimum Moisture Content (OMC)\u003c/p\u003e\u003cp\u003e%\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUntreated\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e16.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e13.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e16.92\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.50\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e17.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.50\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e18.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e18.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e19.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e18.56\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cdiv id=\"Sec17\" class=\"Section3\"\u003e\u003ch2\u003e4.2.2 California bearing ratio value (CBR) of black cotton soil with Xanthan gum\u003c/h2\u003e\u003cp\u003eEffect of Xanthan gum on CBR value of soil is tabulated in Table\u0026nbsp;\u003cspan refid=\"Tab12\" class=\"InternalRef\"\u003e12\u003c/span\u003e. Also, Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e13\u003c/span\u003e shows variation of CBR value with different dosage of Xanthan gum. It can be seen that there is 89.47% increase in CBR value after 7 days of curing as compared to untreated black cotton soil.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab12\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 12\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffect of Xanthan gum on California bearing ratio (CBR) value\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDosage (%) of weight of soil sample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003eCalifornia bearing ratio value (CBR) %\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eCuring period (days)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e07\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUntreated\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3.80\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3.90\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.88\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e4.30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e5.89\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e7.20\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e6.56\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e6.23\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec18\" class=\"Section3\"\u003e\u003ch2\u003e4.2.3. Unconfined compression strength (UCS) of black cotton soil with Xanthan gum\u003c/h2\u003e\u003cp\u003eThe effect of Xanthan gum on the unconfined compression strength value was investigated, and the findings are shown in Table\u0026nbsp;\u003cspan refid=\"Tab13\" class=\"InternalRef\"\u003e13\u003c/span\u003e. Also, shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e14\u003c/span\u003e is the fluctuation of unconfined compression strength with different dosages of Xanthan gum, which enhances soil strength and is more predominant with curing. It is observed that the unconfined compression strength of black cotton soil increases by 149.30% when mixed with 1% dosage of Xanthan gum. This occurs because there is direct interaction between fine particles and Xanthan gum strands due to electrically charged clay particles and Xanthan gum bridges the gap between distant particles, enhancing particle alignment and strength improvement. Similar results were reported by Chang et al. [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab13\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 13\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffect of Xanthan gum on cured unconfined compression strength\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSr. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDosage (%) of weight of soil sample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003eUnconfined compression strength (UCS) kN/m\u0026sup2;\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eCuring period (days)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e07\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUntreated\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e64.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e71.12\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e78.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e90.42\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e90.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e98.52\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e98.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e120.40\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e110.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e177.30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e108.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e156.43\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e106.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e152.89\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFrom the above discussions, it is observed that the strength of the soil (CBR and UCS) initially increases with the addition of Terrazyme up to 1.5 ml/100 ml and also for Xanthan gum, but then decreases beyond a certain point. This can be explained by the following factors:\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eOptimal concentration effect\u003c/strong\u003e\u003cp\u003eBoth Terrazyme and Xanthan gum have an optimal concentration range within which they are most effective in improving soil properties. In the initial phase (up to 1.5 ml/100 ml), the addition of Terrazyme enhances the bonding between soil particles and reduces voids, leading to an increase in soil strength. Similarly, Xanthan gum enhances soil cohesion and improves the strength by forming a gel-like matrix that binds the soil particles together.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eOver-stabilization or excessive additive content\u003c/strong\u003e\u003cp\u003eBeyond the optimal concentration, the addition of more Terrazyme or Xanthan gum can lead to over-stabilization, where the excess enzyme or biopolymer content starts to interfere with the natural bonding process. In the case of Terrazyme, excessive enzyme content might lead to an imbalance in the particle arrangement, creating more voids or disrupting the soil's natural structure, thus reducing its strength. For Xanthan gum, adding too much can lead to a situation where the soil becomes too flexible or overly lubricated, reducing its overall stiffness and strength.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eSaturation and dilution effects\u003c/strong\u003e\u003cp\u003eAs the concentration of Terrazyme or Xanthan gum increases beyond a certain point, the soil may reach a saturation threshold where it can no longer effectively absorb or interact with the additives. This can dilute the stabilizing effect and reduce the efficiency of the additives in binding the soil particles, leading to a decrease in strength.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eMechanical behaviour changes\u003c/strong\u003e\u003cp\u003eThe mechanical behaviour of the soil can also change with higher concentrations of additives. For instance, Terrazyme may lead to excessive compaction or increased brittleness at higher concentrations, which can negatively affect the soil's CBR and UCS values. Similarly, excessive Xanthan gum can lead to a reduction in friction between particles, thereby decreasing the overall strength.\u003c/p\u003e\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"4 Conclusions","content":"\u003cp\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eThe natural adhesives Xanthan gum and bio-enzyme Terrazyme were utilized to enhance the black cotton soil collected in Kolhapur, Maharashtra, India. The influence of the curing period was also considered, and samples were cured for 7 days. Both compounds were found to enhance the geotechnical properties of black cotton soil, including maximum dry density, plasticity index, California bearing ratio value and unconfined compression strength. This impact is particularly apparent after curing. Consistency limits decreased with addition of Terrazyme. Plasticity index was also decreased by 39.35%. A 12% increase in maximum dry unit weight was observed. After seven days of curing with a dosage of 1.5 ml per 100 ml of water, the California bearing ratio value increased by 76.31%. Unconfined compression strength increased by 57.79% with 1.5 ml per 100 ml of water dose, after 7 days of curing. It was found that the optimum Terrazyme dose for stabilizing black cotton soil is 1.5 ml per 100 ml of water. Xanthan gum increased the maximum dry unit weight by 13.61% when added 1.5% of soil mass. A seven-day period of 1.0% dosage curing resulted in an 89.47% increase in the California bearing ratio value. Additionally, after 7 days of cure with a 1.0% dosage, unconfined compression strength increased by 149.30%.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eIt can be concluded that both Terrazyme and Xanthan gum can be used as stabilizer for black cotton soils to improve the geotechnical properties with optimum dosage of Terrazyme of 1.5 ml per 100 ml of water and Xanthan gum of dosage 1% by weight of soil treated. Though addition of Terrazyme improved the plasticity index, it was not possible to evaluate consistency limits after addition of Xanthan gum. Mixing of Terrazyme with soil was much easier as it was used along with water, mixing of Xanthan gum may be difficult at the site. Terrazyme and Xanthan gum are effective in increasing soil adhesion and forming dense masses, but Xanthan gum may pose challenges in the field due to its potential for difficulties in mixing.\u003c/p\u003e\u003cp\u003eLimitation of the present study was restricting the sample collection from depths up to 4m. Based on the outputs obtained from the laboratory studies, field applications and practical difficulties can be studies and cost analysis can be done. The present study can be extended to greater depths by collecting samples from boreholes and studying effect of seasonal variation in moisture content on the geotechnical properties. Also, more detailed studies on consolidation and swelling behavior can be undertaken.\u003c/p\u003e"},{"header":"Notations","content":"\u003cp\u003e\u003cem\u003eThe following symbols are used in this paper:\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eCBR = California bearing ratio (%)\u003c/p\u003e\n\u003cp\u003ec \u0026nbsp;= Cohesion (kN/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n\u003cp\u003eC\u003csub\u003ec\u003c/sub\u003e = Compression index\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eC\u003csub\u003er\u003c/sub\u003e = Recompression index\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDFS = Differential Free swell \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eG = Specific gravity\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eLL = Liquid limit (%)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eOMC = Optimum moisture content (%)\u003c/p\u003e\n\u003cp\u003ePL = Plastic limit (%)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePI = Plasticity index (%)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;SL = Shrinkage limit (%)\u003c/p\u003e\n\u003cp\u003ef\u0026nbsp;= Angle of internal friction (\u003csup\u003eo\u003c/sup\u003e)\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eConflicts of interest/Competing interests\u003c/h2\u003e\u003cp\u003eThe authors have no conflicts of interest to declare that are relevant to the content of this article.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e\u003cp\u003eThe authors declare they have no financial interests. No funding was received to assist with the preparation of this manuscript.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eGuruprasad Chavan collected samples, performed testing, prepared figures and tables. Chavan and Savoikar wrote the manuscript and was reviewed by Savoikar.\u003c/p\u003e\u003ch2\u003eAvailability of data and material\u003c/h2\u003e\u003cp\u003eNot applicable\u003c/p\u003e\u003ch2\u003eCode availability\u003c/h2\u003e\u003cp\u003eNot applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003ePashabavandpouri, M.A., Goodarzi, A.R. and Lajevardi, S.H.: Enhancing the Mechanical and Microstructural Properties of Expansive Soils using Industrial Waste, Nano-material and Polypropylene Fibres: A Comparative Study.\u0026nbsp;International Journal of Geosynthetics and Ground Engineering.\u0026nbsp;9, 54 https://doi.org/10.1007/s40891-023-00467-6. (2023).\u003c/li\u003e\n \u003cli\u003eKumar, A., Walia, B. S., and Bajaj, A.: Influence of fly ash, lime, and polyester fibres on compaction and strength properties of expansive soil\u0026rdquo;, Journal of Materials in Civil Engineering, ASCE, Vol. 19, No.3. doi:10.1061/(asce)0899-1561(2007)19:3(242) (2007).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eNayak N. V.: Foundation design manual. Dhanpat Rai Publications, seventh edition, ISBN: 978-93-83182-90-9 (2015).\u003c/li\u003e\n \u003cli\u003eIS 2911-3: Code of practice for design and construction of pile foundations, Part 3: Under-reamed piles (1980).\u003c/li\u003e\n \u003cli\u003eHoltz, W. and Gibbs, H.: Triaxial Shear Tests on Pervious Gravelly Soils. J. Soil Mech. and Found. Div.. 82. 1-22. 10.1061/JSFEAQ.0000004 (1956)..\u003c/li\u003e\n \u003cli\u003eSivakumar Babu, G. L., Vasudevan, A. K., and Sayida, M. K.: Use of Coir Fibres for Improving the Engineering Properties of Expansive Soils. Journal of Natural Fibres, 5(1), 61\u0026ndash;75. doi:10.1080/15440470801901522 (2008).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eTang, Y. H., Bao, C. G., Wang, M. Y., and Ding, J. H.: Experimental Study on the Strength Characteristics of Expansive Soil Reinforced With Synthetic Fibres. Geosynthetics in Civil and Environmental Engineering, 369\u0026ndash;373. doi:10.1007/978-3-540-69313-0_71 (2008).\u003c/li\u003e\n \u003cli\u003eElayaraja, S. and Arumairaj, P. D.: Study on the shear strength of black cotton soil reinforced with geosynthetics, National Conference on Advances in Steel Concrete and Composite Structures, Department of Civil Engineering, Government College of Technology, Coimbatore-13, Vol.1 (2009).\u003c/li\u003e\n \u003cli\u003eBabu, G. L. S., and Chouksey, S. K.: Model for analysis of fibre-reinforced clayey soil. Geomechanics and Geoengineering, 5(4), 277\u0026ndash;285.\u0026nbsp;doi:10.1080/17486021003706804 (2010).\u0026nbsp;.\u003c/li\u003e\n \u003cli\u003eSrivastava, A., Pandey, S., and Rana, J.: Use of shredded tyre waste in improving the geotechnical properties of expansive black cotton soil. Geomechanics and Geoengineering, 9(4), 303\u0026ndash;311. doi:10.1080/17486025.2014.902121 (2014).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eAshango, A. A., and Patra, N. R.: Behaviour of Expansive Soil Treated with Steel Slag, Rice Husk Ash, and Lime. Journal of Materials in Civil Engineering, 28(7), 06016008. doi:10.1061/(asce)mt.1943-5533.0001547 (2016).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eGobinath, R., Ganapathy, G. P., Akinwumi, I. I., Kovendiran, S., Hema, S., and Thangaraj, M.: Plasticity, strength, permeability and compressibility characteristics of black cotton soil stabilized with precipitated silica. Journal of Central South University, 23(10), 2688\u0026ndash;2694.\u0026nbsp;doi:10.1007/s11771-016-3330-7 (2016).\u0026nbsp;.\u003c/li\u003e\n \u003cli\u003eDalal, S. P., Patel, R., and Dalal, P. D.: Effect on Engineering Properties of Black Cotton Soil treated with Agricultural and Industrial Waste. Materials Today: Proceedings, 4(9), 9640\u0026ndash;9644. doi:10.1016/j.matpr.2017.06.240 (2017).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eEtim, R. K., Eberemu, A. O., and Osinubi, K. J.: Stabilization of black cotton soil with lime and iron ore tailings admixture. Transportation Geotechnics, 10, 85\u0026ndash;95. doi:10.1016/j.trgeo.2017.01.002 (2017).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eUppal, H. L., and Chadda, L. R.: Physico-chemical changes in the lime stabilization of black cotton soil (India). Engineering Geology, 2(3), 179\u0026ndash;189. doi:10.1016/0013-7952(67) 90017-8 (1967).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u0026nbsp;Raychaudhuri, S. P., Roy, B. B., Gupta, S. P. and Dewan, M. L.: Black soils of India. Nat. Inst. Sci. India, 47 (1963).\u003c/li\u003e\n \u003cli\u003eWild, S., Kinuthia, J. M., Robinson, R. B., and Humphreys, I.: Effects of ground granulated blast furnace slag (GGBS) on the strength and swelling properties of lime-stabilized kaolinite in the presence of sulphates. Clay Minerals, 31(03), 423\u0026ndash;433. doi:10.1180/claymin.1996.031.3.12 (1996).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eAl-Taie, A., Disfani, M., Evans, R., Arulrajah, A., and Horpibulsuk, S.: Volumetric Behavior and Soil Water Characteristic Curve of Untreated and Lime-Stabilized Reactive Clay. International Journal of Geomechanics, 19(2), 04018192. doi:10.1061/(asce)gm.1943-5622.0001336 (2019). \u0026nbsp;\u003c/li\u003e\n \u003cli\u003eOza, J. B., and Gundaliya, P. J.: Study of Black Cotton Soil Characteristics with Cement Waste Dust and Lime. Proceedia Engineering, 51, 110\u0026ndash;118. doi:10.1016/j.proeng.2013.01.017 (2013).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eDas, A. and Soni, D. K.: Effect of the ground granulated blast furnace slag (GGBS) and lime mix on the hydraulic conductivity of expansive clay. International Conference on Recent Trends and Challenges in Civil Engineering December 12-14, MNNIT Allahabad, India (2014).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eYi, Y., Gu, L., Liu, S., and Puppala, A. J.: Carbide slag\u0026ndash;activated ground granulated blastfurnace slag for soft clay stabilization. Canadian Geotechnical Journal, 52(5), 656\u0026ndash;663. doi:10.1139/cgj-2014-0007 (2015). \u0026nbsp;\u003c/li\u003e\n \u003cli\u003eSaride, S., and Dutta, T. T.: Effect of Fly-Ash Stabilization on Stiffness Modulus Degradation of Expansive Clays. Journal of Materials in Civil Engineering, 28(12), 04016166.\u0026nbsp;doi:10.1061/(asce)mt.1943-5533.0001678 (2016).\u003c/li\u003e\n \u003cli\u003eVerma, H., Ray, A., Rai, R., Gupta, T., and Mehta, N.: Ground improvement using chemical methods: A review. Heliyon, 7(7), e07678. doi:10.1016/j.heliyon.2021.e07678 (2021).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eChang, I., Im, J., Prasidhi, A. K., and Cho, G. C.: Effects of Xanthan gum biopolymer on soil strengthening. Construction and Building Materials, 74, 65\u0026ndash;72. doi:10.1016/j.conbuildmat.2014.1 (2015).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eSoldo, A., and Miletić, M.: Study on Shear Strength of Xanthan Gum-Amended Soil. Sustainability, 11(21), 6142. doi:10.3390/su11216142 (2019).\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eBegum, A. S., Prasada Raju, G. V. R., Prasad, D. S. V., and Anjan Kumar, M.: \u0026nbsp;Influence of Terrazyme on compaction and consolidation properties of expansive soil. In Problematic Soils and Geoenvironmental Concerns: Proceedings of IGC 2018 (pp. 525-535). Singapore: Springer Singapore (2020).\u003c/li\u003e\n \u003cli\u003eChavan, G.A. and Savoikar, P.: Characterization of Black Cotton Soil in Kolhapur Region. Indian Geotechnical Journal. 53, 1454\u0026ndash;1467. https://doi.org/10.1007/s40098-023-00766-9 (2023).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"black cotton soil, characterization, improvement, stabilization","lastPublishedDoi":"10.21203/rs.3.rs-7142521/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7142521/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eBlack cotton soil, are expansive in nature, posing challenges for construction activities. Structures resting on these soils may crack and sink as a result of the soils' seasonal expansion during the monsoon and contraction during the summer. Special techniques such as soil stabilization, the use of deep foundations, and proper drainage systems are employed to mitigate the effects of swelling and prevent damage to buildings. In the present study, the extensive literature survey is conducted on different type of stabilizers such as various fibres, agricultural by-products, industrial by-products, chemical stabilizers, natural adhesives, and bio-enzymes used for improvement in geotechnical properties of black cotton soils. The natural adhesives Xanthan gum and bio-enzyme Terrazyme are used for this research study to enhance the black cotton soil collected in Kolhapur, Maharashtra, India. Both compounds were found to increase the qualities of black cotton soil, including plasticity, California bearing ratio, and unconfined compression strength. When compared to Terrazyme, Xanthan gum increases unconfined strength at a dose of 1% of soil mass. Terrazyme dose of 1.5 ml per 100 ml of water enhanced the California bearing ratio by 76.32%. Terrazyme and Xanthan gum are effective in increasing soil adhesion and forming dense masses, but Xanthan gum may pose challenges in the field due to its potential for difficulties in mixing.\u003c/p\u003e","manuscriptTitle":"Use of Bio-enzymes and Natural Adhesives for Improvement of Geotechnical Properties of Black Cotton Soils","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-19 16:28:49","doi":"10.21203/rs.3.rs-7142521/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ceadc803-09d1-434f-a1ad-2db27e132375","owner":[],"postedDate":"August 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-15T10:24:08+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-19 16:28:49","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7142521","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7142521","identity":"rs-7142521","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}