Mass transport (moisture and ions) at the steel-concrete interface is closely related to corrosion of rebar in reinforced concrete structures. Thus, in the model simulating mass transport, the structure of the steel-concrete interface must be well represented. In this study, an image-based local homogenization method is proposed based on images taken in the scanning electron microscope (SEM) under the backscattered electron (BSE) detector. According to the gray level of the image, porosity can be calculated and then proposed equations are used to associate the transport properties (sorption isotherms, diffusion coefficients and permeability) with porosity. Experimental data of chloride concentration taken from the literature are used to validate the proposed method and a good agreement with simulated results them is found
