Restoration of Bond Strength for Fire-Damaged RC Elements

Abstract

Reinforced concrete structures are vulnerable to high temperature conditions such as those during exposure to fire. The exposure of reinforced concrete (RC) structural elements to high temperature leads to loss in the mechanical properties of concrete and most importantly loss of bond between concrete and steel rebars. Recovering the structural integrity of heat-damaged RC elements requires extensive repair and rehabilitation works. This thesis contains details of an experimental and analytical study conducted to evaluate the residual bond strength between concrete and steel rebars after subjected to elevated temperature and to investigate the effective repairing materials and techniques in restoring bond strength for heat –damaged concrete elements. The beam-end specimens were tested in three conditions, in ambient temperature, after subjected to elevated temperature of 800 °C, or after subjected to 600 °C. Steel fiber reinforced concrete and concrete were used as the repairing materials. Shallow and deep repair techniques were used as repairing techniques. The tested rebar was embedded in two concrete covers 30 and 50 mm. The embedded lengths 5Ø and 8Ø were conducted in this study.