Petrophysical properties of selected Quaternary building stones in western Austria
Michael Unterwurzacher, Ulrich Obojes, Roland Hofer, Peter W. Mirwald, 2010. "Petrophysical properties of selected Quaternary building stones in western Austria", Natural Stone Resources for Historical Monuments, R Přikryl, Á Török
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In west Austria Quaternary building stones, such as lithic breccias of alluvial fans and talus slopes or calcareous spring tufa, have been frequently used as building stones since Roman times. Spring tufas are a widely used building material of historical objects in west Austria. This porous calcareous rock, formed by carbonate precipitation from calcium carbonate supersaturated spring waters, is an appreciated building stone: easy to quarry, lightweight, easily workable and relatively resistant to weathering. The Hötting Breccia, a lithified talus and alluvial breccia, has only been extracted in a few quarries near Innsbruck/Tyrol, however. Many of the mediaeval buildings of the towns of Innsbruck and Hall are built of this decorative type of stone. Petrography, mineralogical composition, porosity parameters and hygric properties have been investigated in this study from two tufas and one breccia occurrence. The results obtained reveal that these Quaternary stones, being formed at the Earth's surface, exhibit pore properties and hygric behaviour which differ considerably from other stone materials which have been subjected to the physical-chemical formation conditions of the upper Earth crust. This has implications for their workability, internal stability and weathering behaviour.