Evolution and decay processes ain the Villamayor and Zamora sandstones

Abstract

In this paper, we report data on the nature, composition and behaviour of the Villamayor and the Zamora Sandstones under a semi-arid continental climate regime and the almost complete absence of air pollution. The main factors and mechanisms involved in the decay of the building sandstones are essentially related to the transport and later crystallisation of soluble salts from run-off and subsurface waters, sharp temperature changes (termoclasty), freezing (gellifraction), filtration throught roofs or capillariry in the lower parts of the buildings (wetting/drying). The Villamayor sandstone shows a more acute of decay than the Zamora sandstone owing to its greater porosity and high content in phyllosilicates (smectite and palygorskite).