Abstract: Transport of moisture is the main cause of the durability problems of concrete. In the light of the similarity between concrete bulk and slice in terms of moisture transmission, we investigated into the law of moisture transport in the wetting process of concrete in pure water environment and salt solutions of different concentrations on the basis of parallel-tube adsorption theory and Washburn equation. Moreover, we also simulated the law of moisture transmission in the boundary layer of concrete taking concrete slices as the object. Our findings suggest that the wetting process of concrete’s boundary layer is dominated by capillary adsorption, and the existence of ions does not change the basic law, but only affects the transmission rate of moisture. The mass transmission model is fitted and verified through experimental data, and on this basis, the saturation change model of the concrete boundary layer is deduced, which appropriately describes the law of saturation change of the concrete boundary layer in one-dimensional transmission direction.

Key words: concrete, moisture transmission, boundary conditions, experimental study, bulk, slice