Effect of corrosion method of the reinforcing bar on bond characteristics in reinforced concrete specimens

Reinforcing bars embedded in concrete structures are corroded, for example, by the ingression of chlorides from sea sand and deicing materials. Such corrosion induces interior pressure which is increased in the surrounding concrete due to expansion of rebar. As a result, the bond strength and stiffness of reinforcing bar are reduced and the structure eventually undergoes deterioration of concrete which lead to drastic shortening of service life of concrete structures. Accordingly, many researchers have investigated on relationship of bond characteristics of reinforced concrete (RC) members and corrosion of the reinforcing bar. One technique to define the relationship is to artificially induce rapid corrosion of the reinforcing bar. However, this artificial corrosion method failed to provide an accurate representation of real conditions and led to overestimation of the performance of RC members in real situations. The objective of this paper is to investigate the differences of bond characteristics in RC members corroded by artificial rapid and natural corrosion methods. The evaluation on technique suitability was also performed. sults of this investigation indicated that the failure pattern and the critical corrosion level at which the bond capacity failed, varied depending on the RC corrosion method. The RC specimens were deteriorated at a low corrosion stage under natural corrosion conditions. More attention is needed to be given to the rapid artificial RC member corrosion method. Non-destructive test (NDT) methods were also applied to RC specimens for investigation of the naturally corroded members. A formula of corrosion area prediction from NDT was proposed.