Читать книгу Monument Future - Siegfried Siegesmund - Страница 181

In this study, volcanic tuffs from Europe (Germany and Hungary), Asia (Armenia) and North-America (Mexico) are compared. The physical properties (density, porosity and pore-size distribution, strength) and mineralogical composition of basic, intermediate and acid volcanic tuffs were measured in laboratory conditions aiming to evaluate these parameters in terms of stone durability. The colour of rhyolitic to andesitic tuffs, the amount of lithic clasts and the proportion of groundmass vary. The mineralogical composition, porosity and textural characteristics of the studied tuffs are very different. The comparative analysis suggested that clay content and distribution within the pores, the amount of glassy groundmass, porosity and pore-size distribution, as well as hygric swelling and thermal behaviour of the tuffs, are the main control factors of the durability.