Theoulakis, P and Moropoulou, A (1999) Salt Crystal Growth as Weathering Mechanism of Porous Stone on Historic Masonry. Journal of Porous Materials, 6 (4). pp. 345-358. ISSN 13802224
Full text not available from this repository.Abstract
It is well known that in porous stones, NaCl precipitation on and beneath a surface depends on the solution supply and the evaporation rate according to the microclimate and the effective pore structure. In the present work, the study of salt crystal growth mechanisms in large heterogeneous systems like porous stone masonries is attempted. The historic masonries of the Medieval City of Rhodes act as a pilot, due to the intense marine environment and the climatic conditions in favour of NaCl crystallization into the highly porous stones. Weathered monument samples from various depths on masonries exposed to the sea are examined systematically under SEM and EPMA. The obtained results permit the differentiation of crystal growth patterns occurring during distinguished phases of the evaporation process within the porous stone masonry in depth. In the first phase, salt crystals grow favourably in the larger pores, connecting with the empty evaporation channels, and being supplied by solution from the next smaller pores. The isometric crystal habits attaining an equilibrium form correspond to those growing immersed in the solution, when a granular crust is formed. In a second phase, the crystals already exceed the pore size and overlap other smaller pores. As the rate of evaporation exceeds the solution supply, the solution retires and the substrate dries out, the area where the crystal contacts the solution is reduced, and consequently, columnar crystals grow. The pressure exerted by crystallization against the pore walls, when the crystals filling entirely the coarse pores continue growing, leads to disruption.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Historic building; Masonry; Salt crystallisation; Porous materials; Stone decay; Weathering |
| Subjects: | ?? Salt ?? English > Damage functions > Salt damage ?? monitor ?? |
| Depositing User: | Anna Samuelsson |
| Date Deposited: | 28 Apr 2008 13:00 |
| Last Modified: | 04 Apr 2017 12:51 |
| URI: | http://eprints.sparaochbevara.se/id/eprint/266 |
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