Surface Features of the Giovanni Rasori marble monument (1840, Milan): chemical characterization of degradation and past restoration interventions

Andrea Bergomi, Paola Fermo, Chiara Lombardi, Michela Pirovano, Antonino Fiorentino, Mattia Borelli, Mario Colella, Valeria Comite
Abstract:
The conservation of outdoor heritage in urban environments requires careful analysis of degradation processes induced by atmospheric pollutants. This study presents the results of a scientific investigation on the marble monument of Giovanni Rasori (1840), located in Milan, a city affected by heavy traffic and industrial emissions. Exposed for decades to an outdoor polluted environment, the monument exhibited visible signs of surface alteration. Analytical techniques, including SEM-EDX and ATR/FTIR, revealed that the primary degradation process was sulfation, confirmed by the presence of gypsum on the marble substrate. Moreover, the detection of Ti in localized areas of certain micro-fragments suggests the possible use of a whitening agent or pigment during past restoration works. Additionally, the co-presence of elements such as Si, Al, and Fe may be linked to atmospheric dust or to abrasive residues from earlier cleaning practices, such as micro-sandblasting, historically used in stone conservation. These findings contribute to a deeper understanding of marble surface transformations in polluted urban contexts.
Download:
IMEKO-Metroarchaeo-2025-148.pdf
DOI:
10.21014/tc26-2025.148
Event details
IMEKO TC:
TC26
Event name:
TC26 MetroArcheo Conference 2025
Title:

Metrology for Archaeology and Cultural Heritage

Place:
Bergamo, ITALY
Time:
15 October 2025 - 17 October 2025