Correlation Between Electrochemical Impedance Spectroscopy and LCR Parameter Meter in the Corrosion Processes of Steel‐Reinforced Mortars

Measuring corrosion in reinforcing steel embedded in mortar or concrete is a challenge that must always be considered. Electrochemical impedance spectroscopy (EIS) provides a useful estimation of corrosion rates, but its complexity and sensitivity mainly confine it to laboratory testing. On the other hand, the LCR meter, a small and portable device commonly used for testing circuits, measures impedance, capacitance, and inductance. Applying the EIS approach, which views elements as arrays of resistances and capacitances, allows inferring that it is possible to measure corrosion with the LCR meter by comparing it with EIS. To explore this, tests were conducted on cylindrical mortar samples with reinforcing steel, following a 2 × 3 factorial design with three replicates. After accelerated corrosion, a linear relationship was observed between the Rct parameter from EIS and the 100 Hz impedance from the LCR meter in samples subjected to impressed current. However, in samples subjected to carbonation, the techniques could not be correlated, possibly because the carbonation front had not yet depassivated the steel. The combination of chlorides and carbonation showed opposite effects: chlorides reduce the impedance of the mortar cover, while carbonation increases its resistivity. These results are a first step towards developing a new corrosion detection method based on the LCR meter, offering advantages in handling, time, cost, and portability.