Bond–Slip Models for Corroded RC Members Exposed to Fire

Abstract

This paper presents the latest research findings investigating RC members’ residual load–slip response to combined damage caused by corrosion and fire. The idea is to simulate an accidental fire in old or aging structures situated in an aggressive environment such as along the coastlines. The research involved evaluating the response of an RC bond exposed to corrosion and subsequently to elevated temperatures. Pullout bond tests were carried out on cylindrical bond specimens as per standard recommendations following the exposure to accelerated corrosion and elevated temperatures at steady state. Specimens were corroded in the range (2%–20%) as mass loss followed by exposure to elevated temperatures to achieve the steady state (200°C–800°C). The residual load–slip response is examined with the aid of displacement-controlled pullout tests. A set of LVDTs equipment was used to precisely obtain the ultimate bond strength and the steel bar’s slip relative to the concrete. The study presents distinct load–slip response curves depicting the overall load–slip mechanism of an RC bond. The results indicate significant changes in the load–slip response due to the two nonlinear phenomena’s superimposition. The bond strength degradation and the load–slip response have been modeled to predict RC members’ bond behavior exposed to corrosion–temperature interaction.