Responses and post-impact properties of ultra-high performance fibre reinforced concrete under pendulum impact

The present research aims to understand the response and post-impact properties of ultra-high performance fibre reinforced concrete (UHPFRC) under low-velocity impact. An UHPFRC applying coarse basalt aggregate is developed by using the optimized particle packing theory and considering the mineral oxide engineering and steel fibre utilization. A reliable low-velocity impact method employing pendulum impact test set-up is designed and applied. The results show that the residual strength of UHPFRC beams after impact follows ‘-ex’ law with the number of impact, while the residual rigidity, toughness and impact resistance tend to linearly decrease. The rigidity and toughness are more appropriate indicators than ultimate bearing capacity based on the analysis on damage index. An analytical model is proposed to predict the residual impact resistance of UHPFRC beams with the static property of flexural toughness and validated against the experimental data.