Can drying and re-wetting of magnesium sulfate salts lead to damage of stone?

Magnesium sulfate salts have been linked to the decay of stone in the field and in laboratory experiments, but the mechanism of damage is still poorly understood. Thermomechanical analysis shows that expansion of stone contaminated with magnesium sulfate salts occurs during drying, followed by relaxation of the stress during dehydration of the precipitated salts. We applied thermogravimetric analysis and X-ray diffractometry to identify the salt phases that precipitate during drying of bulk solutions. The results show the formation of 11 different crystal phases. A novel experiment in which a plate of salt-laden stone is bonded to a glass plate is used to demonstrate the existence of crystallization pressure: warping of the composite reveals significant deformation of the stone during re-wetting of lower hydrates of magnesium sulfate. Environmental scanning electronic microscope (ESEM)/STEM experiments show that hydration of single crystals of the lower hydrates of magnesium sulfate is a through-solution crystallization process that is only visible at a small scale (~μm). It is followed by growth of the crystal prior to deliquescence. This demonstrates that crystallization pressure is the main cause of the stress induced by salt hydration. In addition, we found that drying-induced crystallization is kinetically hindered at high concentration, which we attribute to the low nucleation rate in a highly viscous magnesium sulfate solution.

[1]  G. Scherer,et al.  The chemomechanics of sodium sulfate crystallization in thenardite impregnated limestones during re-wetting , 2011 .

[2]  R. Spencer.  Sulfate Minerals in Evaporite Deposits , 2000 .

[3]  P. Lopez-Arcea,et al.  Deterioration of dolostone by magnesium sulphate salt : an example of incompatible building materials at Bonaval Monastery , Spain , 2008 .

[4]  J. Paulik,et al.  Dehydration of magnesium sulphate heptahydrate investigated by quasi isothermal—quasi isobaric TG , 1981 .

[5]  G. Scherer,et al.  Crystallization of sodium sulfate salts in limestone , 2008 .

[6]  D. Vaniman,et al.  Experimental stability of magnesium sulfate hydrates that may be present on Mars , 2007 .

[7]  C. Rodriguez-Navarro,et al.  Salt weathering: influence of evaporation rate, supersaturation and crystallization pattern , 1999 .

[8]  Michael Steiger,et al.  Crystal growth in porous materials—I: The crystallization pressure of large crystals , 2005 .

[9]  G. Scherer,et al.  Advances in understanding damage by salt crystallization. , 2010, Accounts of chemical research.

[10]  P. Jacobs,et al.  The role of saline solution properties on porous limestone salt weathering by magnesium and sodium sulfates , 2007 .

[11]  A. D. Jensen,et al.  Efflorescence and breakdown of building materials , 1989 .

[12]  T. Mukerji,et al.  The Rock Physics Handbook: Contents , 2009 .

[13]  Michael Steiger,et al.  Crystal growth in porous materials—II: Influence of crystal size on the crystallization pressure , 2005 .

[14]  B. Jolliff,et al.  Phase transition pathways of the hydrates of magnesium sulfate in the temperature range 50°C to 5°C: Implication for sulfates on Mars , 2009 .

[15]  C. Correns,et al.  Experimente zur Messung und Erklärung der sogenannten Kristallisationskraft , 1939 .

[16]  G. Scherer,et al.  Crystallization pressure exerted by in-pore confined crystals , 2009 .

[17]  B. Clark,et al.  The salts of Mars , 1981 .

[18]  C. Rodriguez-Navarro,et al.  Mechanism and kinetics of dehydration of epsomite crystals formed in the presence of organic additives. , 2007, The journal of physical chemistry. B.

[19]  S. Faraone,et al.  Advances in understanding and treating ADHD , 2011, BMC medicine.

[20]  A. Bourgès.  Holistic correlation of physical and mechanical properties of selected natural stones for assessing durability and weathering in the natural environment. , 2006 .

[21]  Olivier Coussy,et al.  Deformation and stress from in-pore drying-induced crystallization of salt , 2006 .

[22]  G. Scherer.  Stress from crystallization of salt , 2004 .

[23]  Jeffrey S. Kargel,et al.  Hydrated states of MgSO4 at equatorial latitudes on Mars , 2004 .

[24]  Robert J. Flatt,et al.  Salt damage in porous materials: how high supersaturations are generated , 2002 .

[25]  H. Haynes.  ASTM C 88 Test on Soundness of Aggregate Using Sodium Sulfate or Magnesium Sulfate: A Study of the Mechanisms of Damage , 2005 .

[26]  Z. Hashin.  Analysis of Composite Materials—A Survey , 1983 .

[27]  Heather Viles,et al.  Salt Weathering Hazard , 1997 .

[28]  R. Flatt,et al.  Hydration and crystallization pressure of sodium sulfate: A critical review , 2002 .

[29]  J. Gooding.  Soil mineralogy and chemistry on Mars - Possible clues from salts and clays in SNC meteorites , 1992 .

[30]  M. Prat,et al.  Effect of Efflorescence Formation on Drying Kinetics of Porous Media , 2009 .

[31]  David L. Bish,et al.  Magnesium sulphate salts and the history of water on Mars , 2004, Nature.

[32]  Alan G. Jones,et al.  Lithospheric geometry of the Wopmay orogen from a Slave craton to Bear Province magnetotelluric transect , 2009 .

[33]  Eric Doehne,et al.  Deterioration of dolostone by magnesium sulphate salt: an example of incompatible building materials at Bonaval Monastery, Spain , 2009 .

[34]  G. Gülker,et al.  Hydration of MgSO4·H2O and Generation of Stress in Porous Materials , 2008 .