Reliability analysis and experimental investigation of impact resistance of concrete reinforced with polyolefin fiber in different shapes, lengths, and doses

Fiber-reinforced concrete (FRC) in applications such as airport runway pavements, road construction, military bunkers, bridges, and dams are always exposed to short-term dynamic load. The present study follows the laboratory and statistical investigation of the impact resistance of polyolefin fibers reinforced concrete (PFRC). Polyolefin fiber was used in two different shapes (simple and mesh), three different lengths (19, 30, and 50 mm), and replacement percentages of 0.5%, 1%, and 1.5%. In order to evaluate the mechanical properties of PFRC, tests include compressive, indirect tensile, and impact tests. The compressive strength test was performed on 39 cubic samples (10 x 10 x 10 cm) and the indirect tensile strength was measured using 39 cylindrical samples (10 x 20 cm) at the age of 28 days. To investigate the impact resistance of concrete mixtures, 416 concrete discs with dimensions of 6.4 x 15 cm (resulting from cylindrical samples with dimensions of 30 x 15 cm) were subjected to a drop-weight test according to the recommendation of ACI 544. The drop-weight test data including the first crack strength and failure strength were collected. A comprehensive two-parameter Weibull distribution was implemented to accurately check the scattered results from the impact test, and the reliability function was presented. Therefore, the investigation shows that the Weibull distribution has a good performance in predicting the impact failure strength of concrete reinforced with polyolefin fibers and avoids conducting additional costly experiments. In addition, mesh fibers have a better performance than simple fibers in improving the mechanical strength of concrete. Polyolefin fiber with a length of 19 mm recorded better results than other lengths of this fiber.