Crystallization pressure arises when salts precipitate in the pores of stone or concrete. If the pore liquid is supersaturated, the crystal grows toward the pore wall, but does not make direct contact, because of repulsive disjoining pressure. We have recently demonstrated that the repulsion between limestone and sodium sulfate (one of the most damaging salts in nature) is drastically reduced by coating the stone with a few nanometers of polyacrylic acid with very low molecular weight.
Related publications:
Controlling crystallization pressure:
“ Controlling stress from salt crystallization”, J. Houck and G.W. Scherer, to be published in proceedings of 16th European Conf. Fracture, Alexandropoulis, Greece, 2006
“Internal stress and cracking in stone and masonry”, G.W. Scherer, to be published in proceedings of 16th European Conf. Fracture, Alexandropoulis, Greece, 2006
“Materials Science Research for Conservation of Sculpture and Monuments”, G.W. Scherer, R. Flatt, and G. Wheeler, MRS Bulletin, Jan. 2001, pp. 44-50
Background on crystallization pressure and disjoining forces:
“Crystallization in pores”, G.W. Scherer, Cement Concr. Res. 29 [8] (1999) 1347-1358; “Reply to discussion of Crystallization in pores”, G.W. Scherer, Cement and Concr. Res. 30 [4] (2000) 673-675
“Stress from crystallization of salt in pores”, G.W. Scherer, pp. 187-194 in Proc. 9th Int. Cong. Deterioration and Conservation of Stone, Vol. 1, ed. V. Fassina (Elsevier, Amsterdam, 2000)
“Factors affecting crystallization pressure”, G.W. Scherer, pp 139-154 in Internal Sulfate Attack and Delayed Ettringite Formation, Proc. Int. RILEM 186-ISA Workshop, ed K. Scrivener and J. Skalny (PRO 35, RILEM publications, Paris 2004)
“Stress from crystallization of salt”, G.W. Scherer, Cement Concr. Res. 34 (2004) 1613-1624
Background on sodium sulfate:
“Hydration and Crystallization Pressure of Sodium Sulfate: a Critical Review”, R.J. Flatt, G.W. Scherer, pp. 29-34 in Materials Issues in Art & Archaeology VI, MRS Symposium Proc. Vol. 712, eds. P.B. Vandiver, M. Goodway, and J.L. Mass (Materials Res. Soc., Warrendale, PA, 2002)
“Crystallization damage by sodium sulfate”, N. Tsui, R.J. Flatt, G.W. Scherer, J. Cultural Heritage 4 (2003) 109-115