Leaching is a diffusion-reaction phenomenon which takes place when concrete is exposed to poorly mineralized or acid water. Degradation consists in dissolution of calcium and hydroxide ions out of the matrix, which causes an increase in porosity and transport properties of surface concrete. Leaching is accelerated in neutral and acid solutions, and it may be coupled with the ingress of aggressive ions such as chloride, sulfate, magnesium. For this means, this study computed Ca2+ ion content in pore solution theoretically.