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Abstract：
Impact tests on post-fire concrete confined by Carbon Fiber-Reinforced Polymer/Plastic (CFRP) sheets were carried out by using Split Hopkinson Pressure Bar (SHPB) experimental setup in this paper, with emphasis on the effect of exposed temperatures, CFRP layers and impact velocities. Firstly, according to the measured stress-strain curves, the effects of experiment parameters on concrete dynamic mechanical performance such as compressive strength, ultimate strain and energy absorption are discussed in details. Additionally, temperature caused a softening effect on the compressive strength of concrete specimens, while CFRP confinement and strain rate play a hardening effect, which can lead to the increase in dynamic compressive strength by 1.8 to 3.6 times compared to static conditions. However, their hardening mechanisms and action stages are extremely different. Finally, nine widely accepted Dynamic Increase Factor (DIF) models considering strain rate effect were summarized, and a simplified model evaluating dynamic compressive strength of post-fire concrete confined by CFRP sheets was proposed, which can provide evidence for engineering emergency repair after fire accidents.
摘要：
本文使用SplitHopkinson压力棒（SHPB）实验装置对碳纤维增强聚合物/塑料（CFRP）薄板约束的火灾后混凝土进行了冲击试验，强调暴露温度的影响，CFRP层和撞击速度。首先,根据测得的应力-应变曲线，试验参数对混凝土抗压强度等动态力学性能的影响,对极限应变和能量吸收进行了详细讨论。此外,温度对混凝土试件的抗压强度产生软化效应，而CFRP约束和应变率起硬化作用，与静态条件相比，动态抗压强度增加1.8到3.6倍。然而,它们的硬化机制和作用阶段截然不同。最后,总结了9种广泛接受的考虑应变率效应的动态增加因子(DIF)模型，并提出了一种评估CFRP板约束的火灾后混凝土动态抗压强度的简化模型，为火灾事故后的工程抢修提供依据。
