Acoustic Emission Monitoring of Corrosion Damage Propagation in Large-Scale Reinforced Concrete Beams

Abstract

An extensive experimental study was performed to apply acoustic emission (AE) monitoring to assess the bond strength of corroded large-scale RC beam specimens. This paper demonstrates the data obtained from AE monitoring of these RC beams, while being exposed to localized, accelerated corrosion procedures at one of the end sides of each beam. Five RC beams were corroded through an electrically accelerated corrosion process to reach 5, 1, 2, and 3% of steel mass loss. The beams were constantly monitored during the accelerated corrosion tests via half-cell potential (HCP) measurements and three attached AE sensors distributed along the span of the beam. During the test, the corrosion and cover crack initiation were monitored and the crack width measurements were attained daily. The results showed that the analysis of AE signal parameters acquired throughout the corrosion period enabled the detection of both corrosion and cover crack onset earlier than HCP readings and prior to any signs of visual cracking, regardless of sensor location. Acoustic emission parameters examined in this paper {cumulative number of hits, cumulative signal strength (CSS), historic index [H (t)], and severity (Sr)} were shown to be highly correlated with the level of corrosion propagation. The study also presents developed damage classification charts interrelating the results of crack growth and mass losses to the average values of H (t) and Sr. These charts can be used to quantify the level of deterioration of RC structures due to reinforcement corrosion.