CFRP约束高温后混凝土力学性能试验研究

以混凝土经历的最高温度和CFRP布层数为参数进行了CFRP约束高温后混凝土力学性能试验研究。通过实测应力-应变曲线，研究温度和CFRP布层数对CFRP约束高温后混凝土抗压强度、极限应变和初始刚度等力学性能指标的影响规律。试验结果表明，CFRP约束显著影响了高温后混凝土受压破坏形态，并大幅度提高了高温后混凝土强度，说明CFRP约束可作为火灾后混凝土结构的一种有效的抢修与加固措施。同时，综合分析温度软化效应和CFRP约束强化效应对混凝土抗压强度的影响，CFRP约束强化效应处于主导地位。此外，在现有模型的基础上，提出了评估CFRP约束高温后混凝土力学性能的简化模型，经试验结果验证，该简化模型具有良好的精确性与实用性。

EXPERIMENTAL STUDY ON THE MECHANICAL PERFORMANCE OF POST-FIRE CONCRETE CONFINED BY CFRP SHEETS

Compressive tests on post-fire concrete confined by CFRP sheets are carried out. Emphasis was laid on the effect of temperature and number of CFRP layers. According to the measured stress-strain curves, the influence of exposed temperature and number of CFRP layers on concrete mechanical performance such as compressive strength, ultimate strain and initial stiffness is discussed. The test results show that CFRP sheets offer a significant confining effect on the compressive failure modes, and greatly increase the compressive strength of fire damaged concrete. This suggests that CFRP confinement could be an effective method to repair and strengthen concrete structures after fire. Meanwhile, comprehensive analysis on the influence of temperature softening effect and CFRP hardening effect shows that the latter plays a dominant role. Moreover, based on existing models, a simplified model to evaluate the mechanical performance of post-fire concrete confined by CFRP sheets is proposed. Its accuracy and applicability are verified against available test results.