Estimation method of corroded portion of reinforcing steel bar by natural potential measurement

Natural potential measurement is one of the simplest methods to evaluate corrosion of steel bars embedded in concrete. But natural potential has been used only to judge whether corrosion is occurring or not. This study aims to establish the estimation method of corroded portion and amount of corrosion quantitatively by using natural potential. Amperage distribution is calculated using natural potential at the surface of steel bar, which was calculated from natural potential measurement data by FEM. Amounts of corrosion are estimated by integrating cumulative amperage by time. In these processes, all estimation methods are based on electrochemical theories. It becomes possible to know more worthwhile information from estimation analysis based on the result of time-dependent measurement natural potential.