Experimental Study on Bond Performance and Damage Detection of Corroded Reinforced Concrete Specimens

This paper presents the results of an experimental research designed to investigate the combined effects of corrosion rate, concrete cover thickness, and stirrup spacing on the bond performance between reinforcement and concrete of reinforced concrete (RC) specimens. The RC specimens were immersed into sodium chloride solution to eliminate the passivation film on reinforcement. Then, an accelerated corrosion method was applied to corrode reinforcement embedded in concrete specimens. Pullout test was carried out to establish empirical formulas for ultimate slip and ultimate bond strength of RC specimens with three different corrosion rates, different concrete cover thicknesses, and different stirrup spacings. In addition, the bond-slip relation model was developed to predict and evaluate the bond performance of RC specimens. Finally, the ultrasonic technology was used to detect the damage of RC specimens, and the corresponding nonlinear coefficient β was proposed to characterize the damage degree of RC specimens. The susceptibility of β on the damage of specimens was compared with that of ultrasonic velocity, indicating β was more appropriate to evaluate the damage of RC specimens.