Assessment of the unsaturated water transport properties of an old concrete: Determination of the pore-interaction factor

Abstract : In this study all the data needed to describe water transport (drying) within an existing concrete structure were characterized using a simple drying experiment. The properties (desorption isotherm, porosity and the unsaturated water transport properties namely, diffusivity and permeability) were evaluated by postprocessing the weight loss data. Once obtained, the permeability evolution was used to check the validity of the Mualem-van Genuchten equations. It appeared that the default pore-interaction factor value proposed by Mualem (p = + 0.5) is just a rough estimate: the values obtained in this study were all negative. Comparing these values to the literature, the pore-interaction factor seems to be correlated to the van Genuchten's exponent m.