Theoretical Assessment of AC Impedance Spectroscopy for Detecting Corrosion of Rebar in Reinforced Concrete

The applicability of AC impedance spectroscopy (ACIS) for detecting corrosion on rebar in concrete is explored theoretically. Corroding rebar is simulated as a one-dimensional electrical transmission line of twenty one-meter segments embedded in a uniform concrete matrix, with the corrosion being restricted to one segment. The simulations indicate that corrosion can only be detected at very low frequencies (<1 mHz), but that the impedance and the peak voltage monitored at the concrete surface may be used to locate the site of the corrosive attack.