Evaluation of damage progression in concrete structures due to reinforcing steel corrosion using acoustic emission monitoring

Abstract

Acoustic emission (AE) monitoring was employed to detect and identify the extent of degradation resulting from reinforcing steel corrosion in concrete structures. Reinforced concrete samples were subjected to an accelerated corrosion test and corroded until they reached five different levels of mass loss of steel: 1, 2, 3, 4, and 5 %. The corrosion activity of all samples was continuously monitored using attached piezoelectric AE sensors and a multichannel data acquisition system. The results obtained from AE monitoring were analysed and compared to those obtained from half-cell potential (HCP) measurements, the amount of anodic current passing with time, and concrete cover cracking. The study analysed AE signal strength parameters including cumulative signal strength, historic index [H(t)], and severity (Sr) to detect the corrosion initiation, and subsequently, to classify the extent of damage following the corrosion progression. The study also aimed to correlate these parameters to both the degree of mass loss and concrete cover crack width. The results showed that the AE signal strength parameters can be exploited to characterize different degrees of damage from corrosion initiation and up to 5 % steel mass loss. These parameters can be analysed to detect the corrosion initiation earlier than the HCP test. This study also presented damage classification charts that can be used to correlate the level of steel mass loss and/or crack width to the AE signal strength parameters. Given these points, the outcomes of this investigation are substantial for advancing the application of acoustic emission for structural health monitoring in concrete structures.