1. College of Civil Engineering，Hunan University，Changsha 410082，China;
2. Key Laboratory for Wind and Bridge Engineering of Hunan Province，Hunan University，Changsha 410082，China
Abstract：To investigate the mechanical properties of CFRP (carbon fiber reinforced polymer) bar after different elevated temperature exposures，the axial tensile tests and transverse static load tests were conducted on 9 specimens and 15 specimens with different elevated temperatures and pretension ratios，respectively.The results show that when the elevated temperature was lower than 100℃，the axial tensile property，transverse performance of the CFRP bar and the bond property between CFRP bar and RPC (reactive powder concrete) degenerate slightly. In the axial tensile tests，all the specimens fractured after being exposed to elevated temperatures of 30℃ and 100℃，and the tensile strength，ultimate strain and elastic modulus of specimens exposed to the elevated temperature of 100℃ decreased by 2.9%，1.0% and 1.6%，respectively，compared to the specimens exposed to the elevated temperature of 30℃. The failure mode for the specimens exposed to the elevated temperature of 200℃ was sliding failure，and the corresponding average bond strength between the bar and RPC and elastic modulus of the bar was reduced by 34.5% and 9.1%，respectively，compared to the specimens exposed to the elevated temperature of 30℃. In the transverse static load tests，the failure mode of all specimens appeared to be fracture of CFRP bars. As the elevated temperature increased from 30℃ to 200℃，the ultimate cable tension，maximum cable tension increment and transverse breaking force of the CFRP bar decreased，while the ultimate transverse deformation was almost unchanged. As the pretension ratio increased from 0 to 0.34，the maximum cable tension increment，transverse breaking force and ultimate transverse deformation of the CFRP bar decreased，while the ultimate cable tension increasedAdditionally，the formulas were proposed for predicting the ultimate transverse deformation，ultimate cable force and ultimate transverse force of CFRP bars subjected to different elevated temperatures.
