Recycled waste tire fiber as a sustainable reinforcement in compacted sand–bentonite mixture for landfill application

Abstract

A layer of compacted sand-bentonite (CSB) mixture is employed as a liner at the landfill. The formation of desiccation-induced shrinkage cracks can increase the leachate migration into groundwater. The usefulness of the liner system may be endangered if the liner material's strength is insufficient. To address this issue, the CSB barrier can be modified by incorporating with waste tire fiber. This study aimed to assess the undrained shear strength, consolidation, and desiccation-induced crack of mixtures of CSB and reinforced CSB. An analytical model was derived to assess the behaviour of tire fiber composite soil from the experimental result. Positive excess pore water pressure was reduced significantly by the inclusion of tire fiber in the consolidated undrained triaxial test results. By the addition of 15% tire fiber, the effective frictional angle was raised from 21.0° to 24.2°, while the effective cohesion component was increased from 15.0 kPa to 24.2 kPa at the same fiber content. The crack density factor and crack intensity factor of the mixture without tire fiber were much higher than those of the CSB with fiber. By the addition of tire fiber, time for 90% consolidation was reduced, while the coefficient of consolidation increased. Although the permeability increased marginally, but it was within the limiting value. An analytical model adequately captured the stress-strain and pore water pressure responses of all proportion of tire fiber, and the yield surface of the composite was expanded maximally with only 10% tire fiber.