Abstract:
To study the flexural performance of engineered cementitious composite (ECC) beams reinforced with carbon fiber reinforced polymer (CFRP) bars, four-point flexural experimental investigates were carried out on three ECC beams reinforced with CFRP bars, one ECC beam reinforced with glass fiber reinforced polymer (GFRP) bars and one concrete beam reinforced with CFRP bars. The main parameters were the reinforcement ratios, the reinforcement type and the matrix type. The experimental results show that the load-deflection curves of ECC beam reinforced with CFRP bars are similar with the ECC beam reinforced with GFRP bars and concrete beam reinforced with CFRP bars, which have an elastic stage, a working stage with cracks and a failure stage. The reinforcement ratio has a great influence on the flexural performance of ECC beams reinforced with CFRP bars. With the increase of reinforcement ratio, the ultimate bearing capacity of ECC beams is improved, and the ductility performance is gradually weakened. The excellent strain-hardening ability and ductility of ECC materials make the ultimate bearing capacity and deformation of ECC beams with CFRP bars superior to the concrete beam reinforced with CFRP bars. Based on the multi-cracking ability of ECC, the strain distribution on the surface of longitudinal bars is more uniform than that of concrete beams with CFRP bars after cracking. Due to the bridging effect of polyvinyl alcohol (PVA) fiber, a large number of fine cracks appear on the surface of ECC beams reinforced with CFRP bars. When ECC beams reinforced with CFRP bars fail, it could maintain good integrity and self-recovering ability. In service stage, the maximum crack width of reinforced ECC beams presents smaller than that of concrete beams. Finally, a simplified calculation model for ultimate bearing capacity of ECC beams reinforced with fiber reinforced polymer (FRP) rebars is proposed, predicting good agreement with the experimental results.