Influence of curing conditions on the interface bonding properties of CFRP plate–steel

Abstract

To understand the influence of different curing conditions on the interface bonding performance of CFRP-reinforced steel plates, tensile tests were conducted on epoxy resin dog bone specimens and CFRP-reinforced steel plate double lap specimens. The study explored the tensile performance of dog bone specimens under different curing temperature/time conditions and the mechanical properties of double lap specimens under different curing pressures and curing temperature/time conditions. The results indicate that increasing the curing temperature can shorten the curing time of dog bone specimens and also improve their elastic modulus and tensile strength. Elevating the curing pressure, curing temperature, and extending the curing time cause a transition in the failure mode of the double lap specimens from surface fiber stripping of the CFRP plate to a mixed failure dominated by surface fiber stripping and adhesive–steel interface debonding, and the bearing capacity, interface ultimate slip, and peak shear stress of the specimens significantly increase, with the shear stress concentration zone gradually expanding from the loading end towards the free end, simultaneously, the ductility of the specimen increased, and the failure process was delayed. The ultimate load, interface peak shear stress, and ultimate slip of the specimens cured at 90 °C are significantly higher compared to the control group cured at 20 °C and 0.01 MPa. However, with increasing curing time, the rate of growth shows a decreasing trend.