Assessing failure of corroded RC beams under mechanical loads by DIC-AE data analysis

A series of experimental tests were performed in this study to evaluate the static and cyclic loading behaviour of steel reinforced concrete (RC) beam specimens configured in different sizes and steel corrosion levels. Acoustic emission (AE) and digital image correlation (DIC) measurements were carried out to monitor the loading process of these beams, with particular focus on examining the load-induced cracking behaviours and failure modes under the influence of reinforcement corrosion. Experimental findings revealed that, as a consequence of steel rust expansion and the corresponding reactionary confinement in concrete, a small amount of corrosion (approximately 6 % of steel mass loss in this study) increased load-bearing capacity of beam specimens by 8–12 %. Further increase of corrosion to 10–15 % was observed to have significantly changed the steel-concrete bond behaviour in the specimens, and subsequently alter the failure mode of the shear-critical specimens to flexure-controlled. Additionally, AE data analysis successfully revealed the concrete cracking modes in the specimens when loaded. Data analysis results suggested that the corroded specimens emitted AE signals with higher average frequency (AF) values but lower rise angle (RA) values in comparison to the control specimens, regardless of the variations in specimen type and monitoring setup.