Theoretical Model and Experimental Tests on Chloride Diffusion and Migration Processes in Concrete

AbstractThis paper focuses on the effect of the electric field on the thermodynamic model of ion flows in the concrete pore solution. The equation for ion migrations was derived from the mass balance in the multi-component system and material constants. Then, using only one component – chloride ion, a reliable diffusion coefficient was determined from the formulated converse task of the migration equation. Taking into account experimentally obtained distribution of chloride concentrations under the electric field, the diffusion coefficient was determined. The distribution of the chloride concentrations was calculated on the basis of that coefficient. And then, it was compared with the measurement results for concentrations of chlorides penetrating into concrete via diffusion. The lowest mean square error between the experimental and calculated distributions of mass densities indicated the reliable value of the chloride diffusion coefficient