EMI-based monitoring of prestressed concrete beam under chloride-induced corrosion using an embedded piezo sensor

The service life and durability of the prestressed concrete (PC) structures mainly depend on the corrosion resistance of the prestressing strands, wires, or tendons. Once corrosion occurs in the strands, identifying the location and quantifying the phases of corrosion is a very challenging task. Thus, this paper presents a novel way to monitor the corrosion process and identify the deterioration in a PC beam using an embedded piezo sensor (EPS) based on the electro-mechanical impedance (EMI) technique. The accelerated corrosion tests were conducted on a PC beam in which EPS was attached to the prestressing wire inside the beam to monitor the changes in the EMI signature during the corrosion progression. In addition, statistical damage indices such as root mean square deviation is identified to quantify the damage due to corrosion. Further, this study identifies the deterioration in mechanical changes such as stiffness, mass, and damping by extracting the equivalent structural parameters from the raw EMI signatures. Based on qualitative and quantitative results, it is found that the EPS effectively senses the changes at different time intervals during the corrosion process and identifies the damage of corrosion. Also, the equivalent stiffness parameter identified from raw EMI signatures is realistically measuring the material deterioration under corrosion and identifying the corrosion phases. Hence, it is concluded that the EMI technique based on EPS in structural health monitoring of PC beam can accurately assess the deterioration under the effect of corrosion.