A novel damage evaluation method for ultra‐high‐performance fiber reinforced concrete under multiple impact loads

Abstract

In this study, repeated compression tests were conducted for ultra‐high‐performance fiber reinforced concrete (UHPFRC) under three different impact pressures. Results showed that as the impact number increased, the strain rate approximately showed a proportional increase, and the plateau region of the dynamic stress–strain curve became more prominent. Besides, when the repeated impacts increased, the maximum strain and dynamic toughness both exhibited upward trends, while the peak stress decreased. The average toughness was positively correlated with the strain rate. Additionally, under high repeated impact loads, a single crack propagated rapidly within the UHPFRC specimen after single impact. Conversely, cracks propagated from the center to the periphery on the surface of the specimen when repeated loads were low. Furthermore, a quantitative evaluation method for the damage of UHPFRC under repeated impact loads was proposed based on the characteristic parameters of the gray‐level co‐occurrence matrix (GLCM).