FATIGUE OF THE BOND BEHAVIOR OF CORRODED REINFORCED CONCRETE WITH CORROSION-INDUCED CRACKS

Repeated loading and cover cracking can result in bond degradation. Consequently, the mechanical properties of RC members are negatively affected. Through a series of loading tests on eccentric pullout specimens, the present study has investigated the combined effects of repeated loading and corrosion-induced cover cracking on the bond-slip behavior of corroded reinforced concrete. The investigated variables included the number of loading cycles, applied stress level and corrosion level. The test results indicated that the bond behavior of non-corroded or corroded specimens with longitudinal cracks under repeated loading was mainly characterized by accumulated slip increase, whereas the bond strength and the slip at the peak bond stress were not affected. After repeated loading, the bond stress-slip curves showed no significant difference with those of specimens subjected to monotonic loading. It was also found that the surface crack width due to corrosion had significant influence on the bond strength, the slip at the peak bond stress and the residual slip due to repeated loading. Based on the test results of this study and conclusions reported in the literature, a mathematical model for the bond stress-slip relationship of non-corroded or corroded specimens under repeated or monotonic loading was proposed with the surface crack width as the governing parameter. Moreover, an empirical equation for predicting the bond fatigue life was finally developed.