An experimental investigation of mechanical properties of wet-mixed shotcrete reinforced with different types of plastic fiber

Using shotcrete in structural repairing and rehabilitation works, slope protection, tunnel lining and other applications lead to expose shotcrete to tensile stresses and like concrete, shotcrete is weak in tension. For this reason, incorporating fiber is important to eliminate these problems. Plastic fibers were the aim of this study by using it in two types, macro (structural)synthetic (polypropylene) fibers and waste plastic (PET) fibers to reinforced shotcrete with three forms, waste plastic fiber reinforced shotcrete (WFRS), polypropylene fiber reinforced shotcrete (PFRS) and hybrid (waste and polypropylene) fiber reinforced shotcrete (HFRS). All these forms were casted with three volume fractions fibers 0.35, 0.7 and 1% for each form and compared to plain shotcrete with no fibers to evaluate the compressive, tensile and flexural strength for every mix. The test result indicates that the PFRS have better compressive and flexural strength with percentage 0.35 % and 1 % respectively, compared to plain shotcrete, WFRS and HFRS at 7 and 28 days. Similarly, the PFRS with 0.7% have the best splitting tensile strength at 28 days. It is clear from the result that the mixing of synthetic fiber and waste fiber to reinforce shotcrete can enhance the mechanical properties better than of using waste plastic fiber only.