Acoustic emission-based analysis of bond behavior of corroded reinforcement in existing concrete structures

This experimental study exploits acoustic emission (AE) monitoring to assess the bond behavior of corroded bars in reinforced concrete prism samples under pull-out tests. The analysis of AE parameters obtained in this study including amplitude, duration, cumulative number of hits, and signal strength was performed to identify different stages of bond degradation. The results of bond behavior and free end slip were analyzed and compared with the corresponding AE data. An intensity analysis of AE signal strength was also completed to quantify the bond damage using two additional AE parameters: historic index (H (t)) and severity (S-r). The outcomes of AE analysis enabled the detection of early stages of bond deterioration (micro-cracking) as well as identification of the macrocracking stage prior to the occurrence of bond splitting failure. The results also showed a good correlation between AE cumulative number of hits and AE signal strength parameters with the steel-to-concrete bond degradation because of corrosion. Finally, the results of H (t) and S-r were employed to generate intensity classification charts to characterize the stages of micro-and macro-cracking and range of slip of corroded reinforcement. Copyright (C) 2016 John Wiley & Sons, Ltd.