A multi-technique characterization study of building materials from the Exedra of S. Nicolo l'Arena in Catania (Italy)

The S. Nicolo l'Arena Exedra in Catania was built up in 1722 in front of the homonymous Monastery. The facade is composed by natural and artificial stones: Syracuse stone for portals and windows frames, lava stone for the basement and a reddish plaster for plane surfaces, typical materials of the Catania historic buildings. Its color is due to the introduction of the so-called "ghiara" in the finishing mixture. A multi-technique study is here presented: after the obtainment of a detailed surveying of the building surface through the integration of 3D laser scanner and digital photogrammetry techniques, FTIR-ATR, Raman and XRD analysis were carried out to characterize structures, materials and their alteration products.