Dynamic mechanical behavior of strain-hardening cementitious composites under drop weight impact loading

Dynamic mechanical behavior of strain-hardening cementitious composites (SHCC) incorporated with different fly ash content at various curing ages was investigated using drop weight impact test. Direct tensile, compressive and bending tests were conducted on SHCC incorporated with various fly ash content. Two-parameter Weibull distribution was performed to analyze the variation of the results of SHCC after drop weight impact test under various curing ages from the perspective of reliability function. The cracking area ratio and fractal dimension were used to quantificationally investigate the failure characteristics of SHCC after the drop weight impact loading. Results indicate that the tensile, compressive, flexural strength and impact energy absorption capacity of SHCC decrease as the increasing of fly ash content. Impact ductility decreases slightly with the curing age. Single impact energy has an obvious effect on the impact resistance of SHCC, and it has a greater influence on the crack width at the initial cracking of SHCC than the crack width at failure. The two-parameter Weibull distribution can estimate the impact properties of SHCC by calculating the impact times at initial cracking and failure of SHCC. Cracking area ratio and fractal dimension can intuitively assess the impact failure characteristics of SHCC. Scanning electron microscopy images show that fibrillation and uneven scratches appear on the surface of the fibers, and the wavy texture can be observed in the axial direction of the fiber, indicating fiber pull-out is a typical failure pattern of the fiber under dynamic loading.