Remaining Shear Capacity of Fire-Damaged High Strength RC Beams after Moist Curing

Abstract

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.