Experimental Study on Compressibility and Rebound Characteristics of Sand Reinforced with Polymer and Fiber

The compressibility and rebound properties of sand reinforced with polymer and fibers were studied with respect to polymer content, dry density, and types and content of fibers using laboratory standard consolidation experiments. The following conclusions are drawn: (1) with the increase in polymer, the compressive coefficient of reinforced sand decreases gradually. Up to 4%, the compressive coefficient decreases slowly and the resilient rate keeps increasing; (2) with the increase in dry density, the compression coefficient decreases rapidly at first and then changes slowly. Up to 1.55 g/cm3, the compression coefficient changes slowly, while the resilient rate keeps increasing; (3) with the increase in fiber content, the compressive coefficient increases and the compressive characteristics of the sand after adding polypropylene fibers become stronger than those of the sand with addition of sisal fibers. The resilient rate of the reinforced sand keeps increasing and the sand reinforced with sisal fiber has a higher resilient rate; (4) the polymer forms a parallel connection model between sand particles, and the curing film can fill the pore between particles. A spatial stereo structure is formed within the sand mixed with fibers reducing the compression characteristics and increasing the resilience under larger vertical loads.