经历不同温升作用后CFRP筋受力性能的试验研究

为研究经历不同温升作用后碳纤维(Carbon Fiber Reinforced Polymer，简称CFRP)筋材的静力性能，以筋材的处理温度为试验参数，完成9个试件的轴向拉伸试验；以筋材的处理温度和初张比为试验参数，完成15个试件的横向受力试验。结果表明：处理温度不超过100℃时，筋材的轴向拉伸、横向受力及与活性粉末混凝土(Reactive Powder Concrete，简称RPC) 间黏结强度等性能的退化程度轻微。对于轴向拉伸试验，经历30℃和100℃温升作用的试件均发生筋材拉断破坏，处理温度100℃试件的抗拉强度、极限应变和弹性模量较30℃试件分别减小2.9%、1.0%和1.6%；经历200℃温升作用的轴向拉伸试件均发生滑移破坏，筋材与RPC界面间的平均黏结强度较常温条件下降低34.5%，弹性模量较30℃试件减小9.1%。对于横向受力试验，所有试件均发生折断破坏。初张比一定时，随着处理温度由30℃增至200℃，CFRP筋的极限索力、最大索力增量及横向破断力均逐渐降低，但横向极限位移变化较小；处理温度相同时，随着初张比由0增至0.34，CFRP筋的最大索力增量、横向破断力及横向极限位移均逐渐减小，但破坏时的极限索力则逐渐增大。提出经历不同温升作用后CFRP筋横向极限位移、极限索力及横向极限荷载的计算公式，并以试验结果验证其适用性。

Experimental study on mechanical properties of CFRP#br#bar after elevated temperature exposure

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 increasedAdditionally，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.