Abstract: To study the flexural performance of externally bonded CFRP-reinforced RC beams under hygrothermal environment, this paper firstly establishes an interface bond-slip model under hygrothermal environment based on the existing two-parameter bond-slip model of FRP-concrete interface and introduces the influence coefficients of humidity and temperature on fracture energy and interface stiffness. Then, the interface model is used to perform finite element numerical simulations on a set of test beams under the action of hygrothermal conditions, and the simulation results are compared with the test results to verify the correctness of the model. Finally, the validated finite element model was used to analyze in depth the effects of factors such as the width ratio of CFRP to concrete and the amount of CFRP reinforcement on the flexural performance of reinforced concrete reinforced beams under different hygrothermal conditions. The results show that the CFRP-concrete bond-slip model established in this paper can effectively simulate the interface performance under the hygrothermal environment; peeling damage mainly occurs in the reinforced beams under the hygrothermal condition, and the flexural load capacity and corresponding deflection of the reinforced beams decrease significantly with the deterioration of the hygrothermal environment; the flexural load capacity of the reinforced beams can be improved by appropriately increasing the width ratio of CFRP to concrete and the amount of CFRP reinforcement under the hygrothermal environment. The flexural load capacity of the reinforced beam can be improved by increasing the width ratio of CFRP to concrete and the amount of CFRP reinforcement.

Key words: strengthened with externally bonded CFRP, hygrothermal environment, bonding interface, peeling, finite element analysis