This study presents an analytical method for estimating the remaining shear capacity of reinforced concrete (RC) beams subjected to high temperature heating and verifies it by experiments. We focused on the mechanism by which the remaining shear capacity of members self-recovers in a humid environment after slow cooling. The authors confirmed that the infiltration of water vapor in the air into concrete after heating caused rehydration of quicklime (CaO) produced by high-temperature heating and self-recovery of material strength. Based upon material experiments, the mechanical model of calcium hydroxide formation by rehydration of quicklime was incorporated into the multi-scale analysis. Using the proposed model of this study, the effect of damage on the remaining strength of damaged members was also investigated. It was confirmed that the series of high temperature heating, slow cooling, moisture absorption, self-healing, and remaining shear capacity could be reproduced by the multi-scale analysis.

本研究提出了一种估算受高温加热的钢筋混凝土 (RC) 梁的剩余抗剪承载力的分析方法，并通过实验对其进行验证。我们重点研究了构件的剩余剪切能力在缓慢冷却后在潮湿环境中自我恢复的机制。作者证实，加热后空气中的水蒸气渗入混凝土，导致高温加热产生的生石灰 (CaO) 再水化，材料强度自行恢复。基于材料实验，将生石灰再水化形成氢氧化钙的力学模型纳入多尺度分析。使用本研究提出的模型，还研究了损坏对损坏构件剩余强度的影响。