A test method for measuring chloride diffusion coefficients through nonsaturated concrete Part I. The instantaneous plane source diffusion case

摘要

A test method is proposed for measuring chloride diffusion coefficients through nonsaturated concrete specimens with controlled water contents. The experimental setup used allows one to supply an initial limited amount of Cl~- to the tested concrete surface. The procedure consists of submitting the surface of concrete specimens to interaction with the products of combustion of PVC, which contain mainly gaseous hydrogen chloride. This interaction yields a limited Cl~- contamination of the concrete surface. After returning the specimens to their controlled humidity exposure conditions, the kinetics of Cl~- transport from the surface inwards may be studied. The experimental Cl~- concentration profiles determined at selected time intervals have been adjusted to a diffusion model of "instantaneous plane source," which takes into account the particular initial and boundary conditions of the experimental procedure, for obtaining the corresponding diffusion coefficients.