Insights from acoustic emission monitoring of damage caused by a slow steel corrosion process in reinforced concrete beams

Abstract

Reinforcement corrosion significantly affects the structural integrity and service life of reinforced concrete (RC) structures. Although acoustic emission (AE) monitoring enables early damage detection and localization, its use during slow natural corrosion and in noisy outdoor environments remains challenging. This study evaluates the feasibility of periodic AE monitoring during natural chloride‑induced corrosion of two pre‑damaged RC beams stored outdoors. Two AE sensor types were assessed under realistic environmental conditions, and a dedicated filtering strategy was developed to separate damage‑related signals from environmental noise. Following main novelties are addressed: (1) the application of periodic AE monitoring rather than continuous AE monitoring, (2) the assessment of slow chloride-induced corrosion in RC instead of accelerated corrosion using a direct current, and (3) the consideration of environmental influences such as rain, wind and solar exposure. The results show that periodic AE monitoring can successfully track damage progression and localize corrosion hotspots. These outcomes underscore the potential of AE monitoring for supporting structural health assessment of RC structures in field conditions.