Finite Element Modeling of Chloride Diffusion in Concrete Using Image Processing for Characterizing Real Shape and Distribution of Different Phases

The objective of this work was to establish an approach to create a finite element based model using the actual image of the surface of the concrete. An image from the polished surface of a concrete specimen was prepared and used to develop the model. The model considered the actual shape of both fine and coarse aggregates and the interfacial transition zone (ITZ) around aggregates. To validate the model, concrete cylinders were exposed to chloride solution and the chloride penetration in concrete cylinders was measured at different times. Results showed that the model could precisely predict the chloride diffusion time, depth, and pattern through concrete. In addition, results indicated that it is imperative to consider all phases including the ITZ around both coarse and fine aggregate, when modeling concrete. The advantages and benefits of the image processing approach for model preparation, including incorporating all concrete phases with their real shapes, were discussed in this paper.