DIFFUSION BEHAVIOR OF CHLORIDE-IONS IN CONCRETE

In the present paper, an analysis of the diffusion behavior of chlorid e ions in concrete is presented. Tn concentrated electrolytic aqueous solutions such as seawater or that typically used in laboratory experi ments, the effect of ionic interaction may significantly reduce the ch emical potential and thus the driving force of the diffusing species. Because of different drift velocities of the cations and chloride ions in the solution, the lagging motion of the cations will also retard t he drift velocity of the chlorides. In addition, both the electrical d ouble layer forming on the solid surface and the chemical binding may significantly interfere with the transport of the chloride ions. As a result, the diffusion behavior of the chloride ions in concrete is a m ore complex and complicated transport process than what can be describ ed by Fick's law of diffusion.