Detection of Defect in Tendon for Pre-stressed Concrete Structures using Electric Signal; Numerical Simulation Studies

The pre-stressing in concrete structures is a popular construction method these days. One of the main problems is degradation of the structures due to the corrosion of the pre-stressing tendon that frequently generates serious damage. Hence, the corrosion detection in tendons is very important to maintain the health of the pre-stressed concrete (PSC) structures. In this study, a numerical simulation is conducted to find the feasibility of detecting corrosions by using an electric signal. For the numerical simulation, COMSOL multi-physics program which can apply the electric signal is used. The simulation is performed by modeling a set of pre-stressing tendons and ducts placed inside of the PSC structure. The ducts are filled with cement grout, and the corrosions are assumed to occur on the pre-stressing tendons. The electric signal applied at a starting point of the PSC ducts and reflected signal at the positions of corrosions is analyzed. It is confirmed that the electric signal varied as the corrosion rates changed. When the corrosion rate increased, the reflected electric signal tended to increase as well. As the corrosion detecting method is developed further, the method can be applied on pre-stressing concrete structures based on the numerical simulation modeling and results. (paper)