Identification of Electric Conductivity and Impedance of Reinforced Concrete by Boundary Element Inverse Analysis

Abstract

Corrosion of steel bars in concrete is a major cause of failure of the reinforced concrete structures. Numerical inverse analysis is expected to become a useful tool for the corrosion detection. In this research, a new method is introduced for identifying the electrical conductivity of concrete and the impedance of steel-concrete interface by using some potential data which are measured on the concrete surface. The identification is based on the boundary element inverse analysis. The inverse analysis was carried out by minimizing the cost function, which is the different between measured and calculated potential in the concrete surface. Laplace equation, which is solved by boundary element method, is used to describe the potential in the concrete domain. An experiment using a concrete block with an embedded rebar is used to demonstrate the effectiveness of the proposed method. The alternative current is impressed into the concrete domain at one point on the concrete surface and the potential is measured at several points on the concrete surface.