ABSTRACT: A method for calculating the mutual diffusion coefficients of an ion influenced by all other coexisting ions in the multicomponent solution for ion movement in concrete is presented in this paper. The method of calculation is based on the generalized form of Fick's first law suggested by Onsager, which is composed of the Onsager phenomenological coefficient and the thermodynamic force between ions that exerted by the gradient of electrochemical potential in the solution. As a result of verification by comparison with the experimental results by Saito H. et al., it is shown that by using the presented method of calculation, the calculated leaching amount of some ions exhibited close to the experimental results
