Method for modeling the transport of ions in hydrated cement systems

A computer-implemented method for determining an ion concentration in solution of each of at least two ions capable of undergoing transport in a cement-based material under a chemical attack and a solid phase profile for at least one component of said cement-based material, said cement-based material having a solid skeleton and pores, said pores being at least one of liquid-filled and vapor-filled, a porosity of said cement-based material being provided, the method comprising the steps of:

• determining a first concentration for each said at least two ions and an electrical potential profile using a transport algorithm, wherein the transport algorithm is a function of a diffusion of said at least two ions, of an adsorption of said at least two ions, of an electrical coupling between said at least two ions and a chemical activity of said at least two ions and wherein an ionic solution of said material is not in equilibrium with various solid phases of an hydrated paste of said cement-based material;
• calculating a corrected concentration from said first concentration for each of said at least two ions and a first solid phase profile for each said at least one component using a chemical reactions algorithm, wherein at least one of a dissolution and a precipitation reactions is accounted for in order to maintain an equilibrium between said ionic solution and said various solid phases of said hydrated paste;
• calculating a changed transport properties profile from said first solid phase profile to take into account an effect of said chemical reactions on said porosity of said material;
• and
• determining an ion concentration for each of said at least two ions and a solid phase profile for each of said at least one component using said changed transport properties profile, said corrected concentration and said first solid phase profile, wherein effects of said chemical reactions on an ionic transport are taken into account by correcting material transport properties
• whereby said ion concentration for each said at least two ions and said solid phase profile for each said at least one component in said cement-based material can be used to evaluate a degradation of said cement-based material.