The influence of lithology and pore-size distribution on the durability of acid volcanic tuffs, Hungary
Published:January 01, 2007
Á. Török, L. Z. Forgó, T. Vogt, S. Löbens, S. Siegesmund, T. Weiss, 2007. "The influence of lithology and pore-size distribution on the durability of acid volcanic tuffs, Hungary", Building Stone Decay: From Diagnosis to Conservation, R. Přikryl, B. J. Smith
Download citation file:
Eight different types of acid tuffs of the Eger Castle (Hungary) and two tuffs from nearby quarries have been studied in detail. Mapping of wall sections reveals that tuffs show weathering forms that are similar to common sedimentary rocks, such as limestones or sandstones. Different lithologies display various weathering features. On pumice-rich tuff ashlars relief due to selective weathering, weathering crusts, multiple flakes and scales occur, while crumbling is common on layered flow tuffs. Conversely, cemented tuff types do not show deep weathering. Pore-size distribution rather than effective porosity controls the weathering susceptibility of tuffs. Frequent larger micropores are the main causes of freeze-thaw-related weathering. Besides clays, newly formed gypsum and calcite are the weathering-related index minerals. Schmidt hammer rebound values mark the weathering process when quarry stones and ashlars of historic walls are compared.
Figures & Tables
Building Stone Decay: From Diagnosis to Conservation
Stone buildings and monuments from the cultural centres of many of the world's urban areas. Frequently these areas are prone to high levels of atmospheric pollution that promote a variety of aggressive stone decay processes. Because of this, stone decay is now widely recognized as a severe threat to much of our cultural heritage. If this threat is to be successfully addressed it is essential that the symptoms of decay are clearly identified, that appropriate stone properties are accurately characterized and that decay processes are precisely identified. It is undoubtedly the case that successful conservation has to be underpinned by a comprehensive understanding of the causes of decay and the factors that control them. The accomplishment of these demanding goals requires an interdisciplinary approach based on co-operation between geologists, environmental scientists, chemists, material scientists, civil engineers, restorers and architects. In pursuit of this collaboration, this volume aims to strengthen the knowledge base dealing with the causes, consequences, prevention and solution of stone decay problems.