Experimental investigation on the flexural performance and damage process of steel fiber reinforced recycled coarse aggregate concrete

The application of recycled concrete requires the reliable information on its flexural performance especially after cracking. In this study, the three-point bending tests were carried out on 40 notched beam specimens to investigate the flexural performance and damage process of steel fiber reinforced recycled coarse aggregate concrete (SFRCAC). The effects of water-cement ratio, recycled coarse aggregate replacement ratio and steel fiber volume fraction on the residual flexural tensile strength and flexural toughness of SFRCAC were analyzed. Moreover, the flexural damage process of the SFRCAC notched beam was explored and analyzed by Acoustic Emission (AE) technology. The results show that the residual flexural tensile strength and flexural toughness of SFRCAC decrease with increased water-cement ratio and recycled coarse aggregate replacement ratio, respectively. Adding steel fibers can effectively improve the residual flexural tensile strength and flexural toughness of SFRCAC. The post-cracking behavior of SFRCAC changes from strain-softening to strain-hardening when steel fiber volume fraction increases from 0.5% to 2%. Finally, the empirical formula of residual flexural tensile strength for SFRCAC has been put forward by analyzing and fitting the test results in this study and related literature.