Petrographic characterization and durability of carbonate stones used in UNESCO World Heritage sites in northeastern Italy

Abstract This paper presents the petrographic and textural characterization of some ornamental limestones widely used in UNESCO World Heritage sites in northeastern Italy, and the assessment of the main decay factors present in the environment where they are employed. Eleven carbonate building materials have been here considered, all commonly present in the built environment of northeastern Italy: two different varieties of Vicenza Stone (Nanto and Costozza), of Verona Stone (Red and Brown Verona), of Asiago Stone (Pink and White Asiago), and of Chiampo Stone (Ondagata and Paglierino), the Istria Stone (Orsera), the Aurisina Stone, and the Botticino Stone. The Carrara marble is also considered, and used as a reference material for the determination of the grain-size distribution. Stone durability was measured by accelerated ageing tests which reproduced freeze-thaw and salt crystallization cycles, among the main causes of deterioration in the region. Petrographic and textural features of these carbonate rocks as well as their porosity resulted to strongly influence their deterioration rate, and their knowledge is therefore essential when trying to predict stone decay as a function of the local environmental forcings.