CHLORIDE DIFFUSION IN POROUS CONCRETE UNDER CONDITIONS OF VARIABLE-TEMPERATURE

A diffusion model is presented in this study for describing diffusion of chloride ion in porous concrete under nonisothermal conditions. The process is to simulate chloride diffusion in concrete exposed to dail y cyclic temperature change. The effects of cyclic and constant temper atures on the chloride diffusion behavior in concretes are investigate d. The time for chloride concentration to reach the corrosion threshol d of the reinforcing steel is determined for a given water-to-cement r atio and thickness of concrete layer. Results indicate that the temper ature and water-to-cement ratio play a vital role in governing the chl oride diffusion process.