Analytical-petrographic Study of Bugnato Degradation of an Ancient Milan Building

Abstract

The ashlar belongs to a classic palace located in the city of Milan (Italy), built in 1883 by a renowned architect of the time. It was studied in detail in order to establish the material it is made of and to highlight its degradation and what caused it. The study was carried out by combining different techniques, for example, a detailed minero-petrographic study was performed, together with classical chemical qualitative and quantitative analyses of all the main cations and anions present, using ion chromatography and UV-Vis spectrophotometry. On the other hand, most of the classic instrumental analytical methodologies were also performed, such as powder X-ray diffractometry, thermal analysis (TG, DTG, and DTA), and SEM spectroscopy. In this way, it was possible to know its composition, hypothesize the origin of the material, highlight the type of degradation, and study the main likely causes. The focus of the research, in our opinion, lies both in the scarcity of published studies regarding this type of artefact, especially if it belongs to the period of the artefact we investigated, and in having demonstrated how chemical and instrumental analyses of different types, can contribute to obtaining different information and how, above all, their results are useful for the mutual validation of the results themselves.