Impact of hydration and gelling properties of guar gum on the mechanism of soil modification

Soil improvement and treatment is a necessity off-late in response to the growing demand for construction spaces. Also, for the emphasis of development in the right direction, it is necessary to select a sustainable and economic technique to treat the soil. Biopolymers present such an eco-friendly alternative material for soil treatment. This study investigates the viability of using guar gum, a polysaccharide for improving the geotechnical properties of clay soil. Guar gum is solvable, non-ionic and hydro-colloidal in nature. The viscosity of guar solutions increases significantly with the gum content but the change in pH with viscosity is very marginal. Its nature to form bio-film and gel plug leads to a substantial decrease in the permeability of the treated matrix. Its tendency to form viscous gels, hydrate and form hydrogen bonds helps in improving the stiffness of the soil matrix and thereby enhances its strength. The treated soil behaves like clay in stiff consistency, failing at higher loads and lower strains with higher stiffness modulus. The formation of hydrogen bonds is a function of time, and hence, the strength of the treated soil–guar mixtures also increases with age. Though biopolymers are susceptible to decay and degradation, the rate of degradation is retarded and strength gain is observed throughout the period of investigation (i.e. 90 days).