Numerical simulation of multi-species transport through saturated concrete during a migration test - MsDiff code

A numerical model, called MsDiff (Multi-Species DIFFusion), based on a finite difference method and on the Nernst-Planck relation has been developed. The concentration profiles for several species (i.e., Cl-, Na+, K+ and OH-), the flux and the potential profile are computed. The simulations allow having a better understanding about the phenomena involved during the transport of different ions into concrete under the influence of an electrical field. The effect of various parameters as the pore solution composition, the non-ideality of the solutions or the chloride binding, is also discussed. Finally, it is shown how the effective diffusion coefficient of chlorides could be measured experimentally by using the LMDC test method.