Effects of elevated temperature to the structural performance of reinforced concrete beams externally bonded with carbon fiber reinforced polymer (CFRP)

The use of Carbon Fiber Reinforced Polymer (CFRP) for the rehabilitation and strengthening of reinforced concrete structures is an innovative alternative that has been attracting great interest from the scientific and technical community. However, heat related structural degradation is a major challenge to the safe design of this alternative. Therefore, a detailed investigation of heat effects on composites is required before further application of this system can be deemed effective. The proposed research aims to investigate the effect of elevated temperatures to the over-all structural performance of the RC beams externally bonded with CFRP. In this study, three types of beam are classified and these are the RC, CFRP and CFRP with cement mortar beams. The heat degradation of these composite materials measured in terms of the loss in its flexural resistance is evaluated for temperatures of 100°C and 300°C and times of exposure of 1 hour and 2 hours. Specimens investigated to various combinations of these variables are tested and the results have known that the flexural strength of CFRP beams is significantly increased as compared to RC beams. However, the increase in the flexural strength provided by the CFRP is determined to be ineffective when expose to various elevated temperature levels depending on the magnitude of the temperature and its corresponding duration. Theoretical analysis using equilibrium equations similar to the flexural analysis of a traditional RC beam is utilized. The comparison of the experimental results with the theoretical values is presented, along with an investigation of the failure modes