Dynamic Mechanical Properties of Red Sandrock-Polypropylene Fiber Reinforced Concrete Composite under Impact Load.

To investigate the dynamic mechanical properties and fracturing behavior of the red sandrock-polypropylene fiber reinforced concrete (R-PPFRC) composite, R-PPFRC composite specimens with different Polypropylene fiber (PPF) dosage were fabricated. Conducted quasi-static compression experiments and dynamic experiments by using Split Hopkinson pressure bar (SHPB) apparatus and testing machine. The fracture characteristics and process of composite specimens were analyzed with the assistance of ultra-high-velocity camera photography. It can be concluded that the dynamic increase factor and the dynamic compressive strength of composite specimens R-PPFRC increase with the increase of load level, indicating a remarkably strain rate strengthening effect. The optimal PPF content is determined finally. The dynamic impact toughness, ultimate toughness, and dissipation energy of R-PPFRC are significantly affected by the load level and the PPF content. The fracturing process of the composite specimen is divided into four phases, crack initiation, crack expansion, crack cluster and ultimate failure. After going through these phases, the ultimate failure pattern is mainly shear and split mixed failure. [ABSTRACT FROM AUTHOR]