Localization and characterization of damage modes in reinforced concrete by means of acoustic emission monitoring during accelerated corrosion and pull-out testing

Reinforcement corrosion is believed to be the most common and most expensive deterioration mechanism in existing reinforced concrete (RC) structures. One of the important damage modes due to corrosion is the deterioration of bond between steel and concrete. In this paper, the Acoustic Emission (AE) technique is evaluated for damage detection, characterization and localization during the corrosion process and during pull-out tests. RC prisms with smooth or ribbed reinforcement were corroded up to different target corrosion levels: 0%, 1.5%, 5% and 10% mass loss. The corrosion processwas accelerated in the lab by imposing a constant direct current while the specimens were partially immersed in a 5% sodium solution. One of the specimens of each rebar type and every corrosion level was monitored continuously with the AE technique. At target corrosion levels, pull-out tests were carried out to study the bond capacity. During these tests, AE monitoring was performed as well on every specimen. Results show that AE is able to detect damage due to corrosion and that the moment of cracking can be determined from cumulative AE energy curves. During pull-out tests, debonding damage was successfully detected, characterized and located from AE curves.