Monitoring and Evaluation of Sandstone Decay Adopting Non-Destructive Techniques: On-Site Application on Building Stones

• Main Authors: Teresa Salvatici, Sara Calandra, Irene Centauro, Elena Pecchioni, Emanuele Intrieri, Carlo Alberto Garzonio
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Heritage
• Subjects: NDT; decay; cultural heritage; <i>Pietra Serena</i>
• Online Access: https://www.mdpi.com/2571-9408/3/4/71

This paper focuses on the characterization approach to evaluate the decay state of <i>Pietra Serena</i> of historic buildings in Florence (Italy). <i>Pietra Serena</i> is a Florentine sandstone largely used in the city especially during the Renaissance; it is a symbol of cultural heritage of Florence and constitutes a large part of the city center, which was named a World Heritage Site by UNESCO in 1982. Unfortunately, many environmental factors negatively affect the stone, increasing damage and the danger of falling material. Any detachment of stone fragments, in addition to constitute a loss in cultural heritage, can be dangerous for citizens and the many tourists that visit the city. The use of non-destructive techniques (NDTs) as ultrasonic and Schmidt hammer tests can quantitatively define some mechanical properties and help to monitor the decay degree of building stone. In this study, the NDTs were combined with mineralogical, petrographical, chemical and physical analyses to investigate the stone materials, in order to correlate their features with the characteristics of the different artefacts in <i>Pietra Serena</i>. Correlations between the NDTs results and the compositional characteristics of the on-site stone were carried out; such discussion allows to identify zones of weakness and dangerous unstable elements.