Bond characteristics of CFRP plated concrete members under elevated temperatures

Fire related structural degradation is a challenge to the safe design of structural members. Carbon fibre reinforced polymer (CFRP) strengthened concrete members show degradation of bond properties with temperature. Therefore, a detailed investigation of heat effects on composites is required before further application of this system can be effective. This paper focuses on a 3D model developed to predict the behaviour of CFRP–concrete composites under fire. Heat transfer analysis was employed to predict the temperature within the adhesive layer of epoxy, which is the most critical part of the member at high temperature. The model showed that the epoxy reached the failure point within a short time under standard fire. The model was also used to predict the required insulation thickness requirement for two-hour and three-hour fire resistance levels. The effects of rate of temperature increase on bond strength of composite structures are demonstrated through numerical analysis. The model results were validated with experimental data.