Study on estimation of content of chloride ions using electromagnetic waves and fluorescent X-rays in reinforced concrete structures

If it has become possible to grasp the chloride ion content inside reinforced concrete structure based on nondestructive inspection, it is possible to detect the progress of deterioration due to salt damage at an early stage, and to take measures for it. This paper introduces the current state of research on the method of estimating the amount of chloride ions in reinforced concrete based on nondestructive inspection using electromagnetic waves, and on the grasp of the distribution of chloride ion amount via minimum-destructive inspection using fluorescent X-rays. As for the estimation of chloride ion content via electromagnetic waves, the authors found the possibility of estimating the average chloride ion content between the concrete surface and rebar position by calculating the conductivity of concrete. However, for the conductivity estimation in the actual structure, further improvement is needed so as to be able to assess the factors that are likely to affect the results. In the estimation of chloride ion content via electromagnetic waves, what is obtained is the average chloride ion content up to the rebar position. In order to estimate the chloride ion content at the rebar position, it is necessary to grasp the chloride ion content distribution from the concrete surface. The authors found the possibility of estimating the chloride ion distribution using fluorescent X-rays. By combining these two methods, the authors found the possibility that the amount of chloride ion at the rebar position could be captured relatively accurately with planar precision. (A.O.)