Evaluation model for durability of concrete in marine environments
Date of Issue1999
School of Civil and Environmental Engineering
The diffusion of chloride is driven by a concentration gradient in the pore solution of concrete. By considering chloride-binding, the properties of pore solution and the pore structure of concrete, the diffusion coefficient of chloride in concrete was defined in three ways, namely, the intrinsic, the effective and the apparent diffusion coefficient of chloride. An electrically accelerated method was proposed to determine the effective diffusion coefficient of chloride in concrete and to investigate the influencing factors. In the proposed method, the Nemst-Einstein equation was adopted to quantitatively relate the diffusion coefficient to the rate of chloride migration under an electric field. The effects of the applied voltage and the thickness of concrete specimen were investigated for optimizing the electrical measurement. For calibration purposes, real time diffusion tests were carried out in parallel to validate the accelerated method. The experimental results have shown that the proposed electrically accelerated method provided a simple, rapid and reliable measurement of the effective diffusion coefficient of chloride in concrete.
DRNTU::Engineering::Civil engineering::Structures and design