Precipitation of sulphate crystals in discontinuities due to evaporation of sulphate solutions is an important contribution to the degradation and swelling behavior of sulphate bearing argillaceous rocks. Although the phenomenon has been studied in laboratory during decades linked to the expansive behavior in tunnels, tests do not adequately reproduce field conditions and all variables involved in the swelling mechanism. Size effect problems and the difficulty in correctly applying hydraulic boundary conditions are the main aspects behind
