Abstract
To evaluate corrosion of reinforcing steel by the attack of chloride ion in concrete under high temperature, influence of temperature on diffusion coefficient of chloride ion in concrete was investigated. At first, two types of test equipments, immersion test type and diffusion cell method type, were manufactured. They were able to control condition of high temperature. Using these equipments, chloride ion diffusion tests were conducted. In the tests, temperature were controlled from 25 to 90°C. Water cement ratios of specimens were changed from 40 to 60%. The result of the tests showed that diffusion coefficient of chloride ion was affected significantly by temperature. The relationship between temperature and diffusion coefficient depended on Arrhenius' equation. The diffusion coefficient decreased as water cement ratio decreased. The tendency does not change even in high temperature. Based on the tests results, equations for evaluating diffusion coefficients of chloride ion in concrete as a function of temperature were proposed.
