The effects of silica fume and polypropylene fibers on the impact resistance and mechanical properties of concrete

Impact resistance and strength performance of concrete mixtures with 0.36 and 0.46 water–cement ratios made with polypropylene and silica fume are examined. Polypropylene fiber with 12-mm length and four volume fractions of 0%, 0.2%, 0.3% and 0.5% are used. In pre-determined mixtures, silica fume is used as cement replacement material at 8% weight of cement. The results show that incorporating polypropylene fibers improves mechanical properties. The addition of silica fume facilitates the dispersion of fibers and improves the strength properties, particularly the impact resistance of concretes. It is shown that using 0.5% polypropylene fiber in the silica fume mixture increases compressive split tensile, and flexural strength, and especially the performance of concrete under impact loading.