Determination of the Water Diffusivity of Concrete Using Drying/Absorption Test Results

Abstract

Abstract Experimental procedures such as ASTM C1585, “Standard Test Method for Measurement of Rate of Absorption of Water by Hydraulic-Cement Concretes,” and ISO12572 have been recently developed to determine the rate of moisture transmission through hydrated cement systems. However, these methods do not provide an actual transport parameter that can be used in chloride ingress models to predict the service-life of concrete structures. This study focused on the development a reliable method to measure the nonlinear moisture diffusivity of concrete. The approach is based on the analysis of drying and wetting experiments performed with concrete samples of different thicknesses. The transport parameter is obtained by using Richards’ water transport model to analyze the mass variations measured during the tests. The method was tested over a wide range of different concrete mixtures produced with different water/cement ratios. Results indicate that the nonlinear function used to reproduce the mass variation curves must exhibit a strong increase for high water content values. The water diffusivity equation derived from this analysis allows reproducing the behavior of concrete during both the drying and absorption experiments using the same water transport model.