Corrosion assessment of reinforced concrete structures based on equivalent structural parameters using electro-mechanical impedance technique

Corrosion of steel reinforcement is one of the main causes of damage and premature failure of reinforced concrete structures, inflicting enormous costs for inspection, maintenance, restoration, and replacement of the infrastructure worldwide. Conventional approaches for detecting corrosion are based on electrochemical techniques such as half-cell potential, impedance spectroscopy, and linear polarization. These techniques are affected by a number of factors and require direct contact with concrete/steel interface. To overcome difficulties with conventional techniques, a new corrosion assessment approach based on the electro-mechanical impedance technique is presented in this article. This article presents results from a series of accelerated corrosion tests performed on rebars embedded in concrete cubes, wherein measurements are made using piezoceramic (lead zirconate titanate) patches surface bonded on rebars via the electro-mechanical impedance technique. The equivalent structural parameters extracted out from the admittance signatures of the lead zirconate titanate patch are calibrated against the level of corrosion based on which a new corrosion assessment model is proposed. The experimental results indicate that the equivalent parameters are effective in detecting and quantifying the corrosion in a realistic manner.