EXPERIMENTAL STUDY ON RC CYLINDERS CONFINED BY CFRP SHEETS UNDER UNIAXIAL COMPRESSION AFTER ELEVATED TEMPERATURE

20 short concrete cylinders confined by CFRP sheets with inorganic adhesive after different elevated temperatures have been loaded under uniaxial compression. The failure mechanism and characteristics of the confined cylinders after elevated temperature have been studied. Based on the test results, the effect of the elevated temperature on the ultimate strength and strain, stress-strain relationship of the strengthened members has also been evaluated. The results show the concrete cylinders confined by CFRP sheets with inorganic adhesive after elevated temperature showed the same failure mechanism with the concrete cylinders at normal temperature. The ultimate compressive strength only decreased by 5% after temperature about 100℃ and were about 85%~90% of the specimens at normal temperature after temperature about 200℃~400℃. After elevated temperature about 100℃, the ultimate compressive strain decreased little and after elevated temperature about 200℃~400℃, the ultimate compressive strain increased by 20%. With the increasing of temperatures, the confining effect of CFRP sheets on the concrete increases. After elevated temperature, the stress-strain curves of concrete cylinders confined by CFRP sheets with inorganic adhesive tended to be flat and there was a compact phase in the stress-strain curves.