Combined application of novel electromagnetic sensors and acoustic emission apparatus to monitor corrosion process of reinforced bars in concrete

Reinforced bar corrosion is a primary reason for performance deterioration of reinforced concrete (RC) structures. Corrosion monitoring of reinforced bars in concrete is a key point to evaluate the durability and the remaining service life of structures, especially in marine environments. Non-destructive tests (NDTs) have been developed as critical methods to assess damage levels inside concrete without external damage based on physical characterization (e.g., electromagnetic response, acoustic signals, etc.). This paper provides a novel idea where home-made electromagnetic (EM) sensors and an acoustic emission (AE) apparatus are combined in order to monitor the entire corrosion process of reinforced concrete beams; meanwhile, a home-made electromagnetic sensor is also upgraded and introduced in this paper. The result shows that it is an excellent option to jointly utilize two kinds of monitoring apparatus to monitor signals from corrosion initiation and subsequent cracking, respectively, based on their own physical performances. Moreover, the reliability of monitoring signals is also highlighted in this paper.