Consolidation Behavior of Compacted Sand–Bentonite–Tire Fiber Mixture for Landfill Application

Compacted sand–bentonite mixtures have been treated as a good substitute for the barrier material at the landfill. At low stress, desiccation-induced moisture variations may cause a reduction in the plastic deformability of bentonite and shrinkage cracking, which can increase the uncontrolled migration of leachates. According to this fact, a series of consolidation and unconfined compression strength (UC) tests were performed on sand–bentonite mixture mixed in a proportion of 30:70 and added with tire fibers in a proportion of 0, 5, 10, and 15%. Results showed that by increasing the tire fiber content the hydraulic conductivity of the mixture increases. For any given fiber content, a higher value of t₉₀ was noticed for the SB30 composite under any range of consolidating pressure. From the shrinkage study, volumetric shrinkage (VS) was reduced as the tire fiber content increased. Surface crack and shrinkage crack developed in the mixture after desiccation and expressed in terms of crack intensity factor (CIF) as well as crack density factor (CDF) both decreased with the inclusion of tire fiber. From UC test, maximum unconfined compressive strength, initial tangent modulus (E_i), secant modulus (E_sec), and energy absorption capacity (EAC) of SB30 composite was evaluated and results showed that the improvement of the composite was significant up to 10% tire fiber, thereafter; it starts to reduce sharply with the inclusion of 15% tire fiber.