Abstract: The pressure exerted by growing crystals of salts or water in porous materials is a major factor to induce deformation and freeze-thaw damage. Theoretical derivations for the crystallization pressure of salt crystals driven by supersaturation and ice crystals driven by temperatures are presented based on the chemical potentials of solutions and crystals, in which the ion interaction is taken into account. The models for the maximum crystallization pressure that the growing crystals in non-ideal solution exert on the pore walls are developed. The pressure from crystallization of salts and water as well as the freezing temperature for solutions of aqueous NaCl and Na₂SO₄ under different concentrations and temperatures are parametrically analyzed, respectively. The results show that for the salt crystals, the crystallization pressure is closely related to the ratio of supersaturation, solution activity and type of salt crystals; for the ice crystals, the crystallization pressure is related to the ambient temperature and solution activity.