Meso-Scale Analysis of Concrete Chloride Diffusion Considering Skins

The diffusivity of chloride ions within the surface layers of concrete (skins) and internal concrete are noticeably different. The diffusivity of chloride ions in the skins follows a gradual change, while it remains stable in internal concrete. In this paper, an N-layered inclusion model, which was divided into finite elements, is presented for the prediction of the diffiisivity of concrete with litho-mogeneous skins of concrete. The validity of the model is verified with experimental data. Furthermore, a multiphase series-parallel coupling improved model of composite materiaLs was developed and used to calculate the apparent diffusion coefficient ofconcrete. The proposed improved model satisfied the upper limits of the parallel model as well as the lower limits of the series model, and was compared to the available experimental data to verify rationality and more accuracy than the N-phase sphere modeL Finally a sensitivity analysis was performed on several parameters.