Experimental and theoretical research on bond performance between CFRP bar and concrete under monotonic and reversed cyclic loading

Abstract

To investigate the bond-slip behaviour between carbon fibre-reinforced polymer (CFRP) bars and concrete, bond stress-slip tests under monotonic loading and reversed cyclic loading were conducted on specimens with different concrete compressive strength, diameters of CFRP bar and embedment lengths. The bond stress-slip performance and bond failure mechanism were analysed. Results showed that with the increasing of concrete compressive strength, the maximum bond stress increased; with the decreasing of diameter of CFRP bar or embedment length, the maximum bond stress increased. For the specimens with the same concrete compressive strength, diameter of CFRP bar and embedment length, the maximum bond stresses under reversed cyclic loading were less than that under monotonic loading. Based on the test data of the specimens with different concrete compressive strengths, diameters of CFRP bar and embedment lengths, the formulae of bond stress-slip curves under monotonic loading, skeleton curves under cyclic loading and feature points in bond stress-slip hysteretic curves were carried out by data fitting. At last, analytical bond stress-slip models of CFRP bar in concrete were proposed, which were suitable for calculating the bond stress-slip curves under both monotonic and reversed cyclic loading. The comparisons between the proposed models and test curves proved that the proposed models could accurately predict the bond stress-slip curves.