Strain rate sensitivity of strain‐hardening fiber‐reinforced concrete subjected to dynamic direct tensile loading

Abstract

This study investigates the effects of matrix strength on the high‐rate tensile resistance and strain rate sensitivity of strain‐hardening fiber‐reinforced concretes (SHFRCs) under direct tensile loading. Two types of deformed steel fiber, hooked and twisted, were reinforced in two matrices, high‐performance concrete (HPC) with compressive strength of 84 MPa and ultra‐high‐performance concrete (UHPC) with compressive strength of 180 MPa. Additionally, an artificial neural network (ANN) based model was proposed to estimate the strain rate sensitivity of SHFRCs subjected to dynamic direct tensile loading. The results showed that HPC produced relatively lower post cracking strength but much higher strain capacity at a high strain rate than UHPC. Moreover, HPC was found to be more strain rate sensitivity than UHPC. Furthermore, the proposed ANN model was an efficient tool for predicting the strain rate sensitivity of SHFRCs. Based on the sensitivity analysis, the contribution of each influence factor on the final strain rate sensitivity of SHFRCs can be determined.