ASSESSEMENT OF THE CHEMICAL AND PHYSICAL ALTERATION OF STONE SURFACES

In the fall of 2007, the Modena City Council started a preliminary diagnostic campaign to create a snapshot of the state of preservation of the Ghirlandina Tower’s external stonework, with the objective of providing mote information to the planner who were preparing its restoration project. From those first results, a diagnostic campaign was coordinated with the DD.LL on the Towers’ four most widely used stone materials. The present work report the results about the stone materials aiming to define, from a chemical, physical and mineralogical perspective, the state of degradation of the stone blocks and stone architectural elements, and to assess factors of degradation on the exterior surface caused by external agents and/ or maintenance treatments applied over centuries.