Impact of Waste Tire Fibre on the Hydro-Mechanical Behaviour of Black Cotton Soil Under Different Pore Fluids

Abstract

In this research, naturally occurring black cotton soil (BCS) was used as a landfill liner to prevent leachate from interacting with groundwater. However, BCS forms cracks when exposed to excessive drying conditions, which might reduce the efficiency of liner material. In general, the addition of fibre can reduce the cracking behaviour of liner material. Massive quantities of waste tire production led to major environmental consequences (water, soil, and air) and posed a hazard to human life. For this cause, this work uses recycled tire fibres at 5, 10, and 15% dry weight proportions as reinforcing materials in BCS to improve liner efficacy. However, it is also essential to consider the leachate effect on liner material, which alters the various parameters of the liner. In this research work, fibre-mixed BCS was tested with two pore fluids (Sodium chloride and Calcium chloride) at 0 (DI Water) and 0.1 N concentrations to represent the leachate impact. This research investigates the impact of recycled tire fibres on the swelling, hydraulic, and strength behaviour of fibre-mixed BCS under the salt environment for landfill application. Results exhibited a drop in swelling pressures, swelling potentials, hydraulic conductivity, and peak strength values with a rise in tire fibre level. Moreover, pore fluids further influence these values, and the variation in results is more prominent with divalent pore fluid than with monovalent pore fluid. In conclusion, based on strength and hydraulic conductivity values, including the effect of pore fluids, test findings indicated that the optimal fibre content is 10%.