Corrosion Detection in Concrete Using Electrical Impedance Tomography

The degradation of steel-reinforced concrete structures frequently leads to failures earlier than the designed service life, and corrosion is one of the major causes of such failures. Therefore, non-destructive testing techniques are urgently needed to evaluate the health status of the structures. This paper explores the feasibility of corrosion detection in a concrete slab using an Electrical Impedance Tomography (EIT) measurement system. On a known location of the slab, chloride-contaminated concrete was used to initiate corrosion on the steel. The experiment was carried out using injected current with the amplitude of 10μA on the top surface of the concrete slab, and the resultant potentials were recorded and used to reconstruct the conductivity image of the slab via inverse algorithms. In addition to the afore-mentioned EIT, half-cell potential was used, and the results were compared with the results from the EIT test. The reconstructed images show that EIT was capable of detecting the location of chloride contaminated concrete and the occurrence and the location of corrosion of the embedded reinforcing steel bars.