Tensile stress–strain relationship of fiber-reinforced concrete with different densities

Abstract

This study aims to propose a rational model to establish the tensile stress–strain relationship of fiber-reinforced concrete (FRC) with different densities based on the general form described in the fib Model Code 2010. To determine the key parameters in the stress–strain model, the inverse analysis was conducted using the load–deflection curve obtained from 85 FRC beam specimens covering a wide range of the compressive strength between 22.0 and 96.5 MPa, concrete density between 1178 and 2306 kg/m3, and fiber reinforcing index (βf) between 0.22 and 5.79. The inverse analysis was iterated until an acceptable consistence was obtained between the experimental load–deflection curve and the prediction by the section lamina approach according to the variation of key parameters in the tensile stress–strain relationship. Subsequently, regression analyses were performed using the values of the key parameters determined in the inverse analysis of each beam. The reliability of the proposed model was examined through comparisons with 48 datasets for tensile stress–strain curves compiled from the uniaxial tensile specimens. The proposed model also assessed the correlation between tensile and flexural strengths of FRC. Moreover, the threshold of βf was identified to distinguish the hardening and softening responses in the stress–strain relationship. The proposed model consistently facilitates the tensile response of FRC, indicating that the normalized root-mean-square error values determined between experimental and predicted curves range between 0.175 and 0.071.