Salt crystal growth as weathering mechanism of porous stone on historic masonry

Theoulakis, P; Moropoulou, A

dc.contributor.author	Theoulakis, P	en
dc.contributor.author	Moropoulou, A	en
dc.date.accessioned	2014-03-01T01:15:09Z
dc.date.available	2014-03-01T01:15:09Z
dc.date.issued	1999	en
dc.identifier.issn	1380-2224	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/13363
dc.subject	salt crystal growth	en
dc.subject	porous stones	en
dc.subject	historic masonries	en
dc.subject	salt decay	en
dc.subject	marine environment	en
dc.subject.classification	Chemistry, Applied	en
dc.subject.classification	Chemistry, Physical	en
dc.subject.classification	Materials Science, Multidisciplinary	en
dc.subject.other	Crystallization	en
dc.subject.other	Evaporation	en
dc.subject.other	Masonry materials	en
dc.subject.other	Pore size	en
dc.subject.other	Porous materials	en
dc.subject.other	Salts	en
dc.subject.other	Scanning electron microscopy	en
dc.subject.other	Weathering	en
dc.subject.other	Historic masonry	en
dc.subject.other	Porous stone	en
dc.subject.other	Salt decay	en
dc.subject.other	Crystal growth	en
dc.title	Salt crystal growth as weathering mechanism of porous stone on historic masonry	en
heal.type	journalArticle	en
heal.identifier.primary	10.1023/A:1009613529869	en
heal.identifier.secondary	http://dx.doi.org/10.1023/A:1009613529869	en
heal.language	English	en
heal.publicationDate	1999	en
heal.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.	en
heal.publisher	Kluwer Academic Publishers, Dordrecht, Netherlands	en
heal.journalName	Journal of Porous Materials	en
dc.identifier.doi	10.1023/A:1009613529869	en
dc.identifier.isi	ISI:000081303100008	en
dc.identifier.volume	6	en
dc.identifier.issue	4	en
dc.identifier.spage	345	en
dc.identifier.epage	358	en