Research on the CFRP-Concrete Interface Model under Fatigue Loading

To investigate the degradation mechanism of the performance of CFRP-concrete bonded interface under fatigue loading, double shear tests with the adhesive layer thickness and stress level as the variables were conducted. The results indicate that under fatigue loading, varying thicknesses of the interface adhesive layer result in different interface failure modes. The strain variations of the CFRP fabric in static and fatigue tests exhibited similar trends, with an increase in bonding thickness leading to higher ultimate load or fatigue cycles. With an increase in the thickness of the adhesive layer, the initial stiffness of the interface decreases, leading to improved deformation performance of the interface. During the second stage of damage development, a thicker adhesive layer led to slower interface damage progression. Under fatigue loading, when the specimen is in the stable crack propagation stage at the interface, a decrease in the load level and an increase in the thickness of the adhesive layer lead to a reduction in the rate of crack propagation. The proposed crack propagation rate model effectively predicted the interface crack propagation process and fatigue life. Finally, the damage and failure process of the interface under fatigue loading was simulated using Fe-safe software, and predictions for its fatigue life were made.