Bond behaviour between CFRP, GFRP, and hybrid C-GFRP tubes and seawater sea sand concrete after exposure to elevated temperatures

The paper provides an overview of the current research on bond performance between fibre-reinforced polymer (FRP) tubes and SWSSC and investigates the bond strength of SWSSC-filled FRP tubes after exposure to different temperatures using push-out tests. A total of 27 samples, including glass FRP (GFRP), carbon FRP (CFRP), and glass-carbon hybrid FRP (HFRP) tubes, were tested to determine the effect of elevated up to 250 degrees C temperatures on the bond performance of the samples. It was observed that exposure to elevated temperatures increased the bond strength of all the tubes. The GFRP and CFRP tubes exhibited the strongest and weakest bond strengths, respectively. Since the inner layer of the HFRP tube was composed of CFRP, the bond strength of HFRP was found to be more similar to that of CFRP samples than GFRP samples. The study concluded that the bond strength of all the samples was predominantly influenced by the surface roughness of the inner tube rather than the fibre type.