Acoustic emission-based analysis of mechanical behavior and damage evolution in corroded RC square columns

Abstract

This study investigates the impact of corrosion on the mechanical behavior, failure processes, and acoustic emission (AE) characteristics of reinforced concrete (RC) columns under uniaxial compression. The results reveal a transition in failure modes from ductile axial compression in uncorroded specimens to brittle shear-compression failure in severely corroded specimens, driven by weakened reinforcement-concrete bonds and reduced stirrup confinement. Corrosion-induced damage significantly reduces stiffness, ductility, and ultimate load-bearing capacity, compromising structural resilience. AE monitoring highlights a three-stage damage evolution—initial damage, damage propagation, and damage failure—with accelerated microcrack initiation and macrocrack coalescence in corroded specimens. The AE frequency distribution shifts from mid-frequency dominance in uncorroded specimens to low-frequency dominance in heavily corroded specimens, reflecting premature macro-damage and structural instability. Additionally, metrics such as AE cumulative signal strength, historical index ($\mathrm{HI}$), and severity value ($S_r$) reveal earlier and more concentrated energy release in severely corroded specimens, underscoring the accelerated degradation and brittle failure mechanisms induced by corrosion. Besides, Through Gaussian Mixture Modeling (GMM) analysis of acoustic emission (AE) parameters, a transition from tensile-dominated cracking in uncorroded specimens to shear-dominated failure in severely corroded specimens was observed. These findings demonstrate the utility of AE technology in characterizing corrosion-induced damage and provide critical insights for real-time structural health monitoring and failure prediction.