Effects of sulfate and freeze–thaw cycles on the bond behavior of CFRP-concrete interface

Abstract

The bonding performance of the interface between carbon fiber-reinforced polymer (CFRP) and concrete is crucial for the safety of concrete structures that are strengthened with CFRP. The reinforced structures in Northwest China are often affected by harsh environmental conditions. In this paper, by using the test method of sulfate and freeze–thaw cycles coupling erosion, the actual erosion environment that may be suffered in this area was simulated, and the bonding performance of CFRP reinforced concrete structures in this environment was studied. Combined with macro and micro experiments, the mechanism of coupled erosion was discussed, and the influence of the above environment on the interface failure mode, interface bearing capacity and interface characteristic values were analyzed. The experimental results show that under the coupling erosion, the failure mode of the CFRP-concrete interface has changed. And the bonding performance of the interface has been significantly reduced. The specific performance is that with the increase of erosion times, the interface bearing capacity is continuously reduced, and the maximum bond shear stress position is gradually moved to the free end. Through induction and analysis of the test data, the bond-slip model of the interface under this condition was established, and the accuracy of the model was evaluated by comparing it with the experimental data.