Study on engineering properties of sand strengthened by mixed fibers and polyurethane organic polymer

A considerable number of engineering hazards are caused by loose internal structure of sands. Thus, many researchers have explored a variety of reinforcement methods. A new reinforcement technique was experimentally evaluated in this study. In particular, a hybrid method with a combination of fiber and polymer was studied. Three different types of fibers (sisal, polypropylene, and palm) in combination with varying concentrations of polymers were experimented to improve the internal structure and strength of sand samples reconstituted at different densities. Through a series of laboratory tests, the compressive and tensile strength variations of different combinations were obtained, and the interaction between fibers and polymer inside the sand was evaluated by scanning electron microscopy (SEM). The experimental results show that the tensile and compressive strength of the reinforced sand increases with the increase of the polymer concentration, sample density, and different fiber combinations. This provides some references for future practical engineering applications.