A novel approach for non-destructive EMI-based corrosion monitoring of concrete-embedded reinforcements using multi-orientation piezoelectric sensors

Abstract

One of the major problems with the durability of concrete structures is the corrosion of embedded rebar in concrete. Early detection of corrosion can prevent catastrophic failures in structures. In this paper, the electromechanical impedance method (EMI) is used for structural health monitoring (SHM) and non-destructive corrosion diagnostics. Compared to previous methods, a new method with the highest accuracy is proposed to evaluate the electromechanical impedance curves. By using piezoelectric (PZT) sensors in concrete, the sensitivity of these sensors to compressive force is investigated through a series of experiments. Also, by bonding two PZT sensors on reinforcing bars in two different orientations, the behavior of specimens, are consistently compared with the EMI measurements. According to the results, a solution for the detection of the corrosion rate and its direction as well as the period of corrosion initiation is proposed based on the variations of the impedance curve during the corrosion.