Relating the Formation Factor and Chloride Binding Parameters to the Apparent Chloride Diffusion Coefficient of Concrete

ASTM C1556-11a [ASTM (2016). Standard Test Method for Determining the Apparent Chloride Diffusion Coefficient of Cementitious Mixtures by Bulk Diffusion] provides a systematic procedure to determine the apparent diffusion coefficient of concrete, which is generally used to assess concrete's ability to resist chloride ingress and to make service life predictions. Although ASTM C1556-11a and other similar tests are widely used, they are time-consuming and expensive to perform. The formation factor can be used as an alternative to rapidly assess the transport properties of concrete; however, it does not consider chloride binding. In this paper, a theoretical relationship is developed to relate the formation factor, chloride binding parameters, and apparent chloride diffusion coefficient. A simplified equation based on this theoretical approach is proposed as an alternative to estimate the apparent chloride diffusion coefficient. The chloride profiles obtained using the apparent diffusion coefficients and surface chloride concentrations from the theoretical approach and ASTM C1556-11a were compared. Combining the formation factor with chloride binding properties provides an alternative to ASTM C1556-11a for determination of the apparent chloride diffusion coefficient and surface chloride concentration.