A Multi-Disciplinary Approach to the Identification and Characterization of Areas of Potential Damage in the Building Materials of Ancient Monuments

Today, the integrated study of historic buildings and their associated artifacts through three-dimensional modelling has become essential. Non-destructive diagnostic techniques are crucial for thorough understanding of the state of conservation of artifacts and stone construction materials used in ancient times. Therefore, it is extremely important to create digital copies that preserve the memory of the analysed forms while also allowing an understanding of the deterioration phenomena that affect historic artifacts, thus guiding restoration efforts. In this paper, the authors present the integrated application of non-destructive geomatic techniques such as terrestrial laser scanning (TLS) in synergy with close-range photogrammetry (CRP) methods, and their integration with non-destructive geophysical diagnostic methods such as ultrasonic indirect tests, ultrasonic transmission tomography, and electrical resistivity. These methods have been further enhanced by complementary petrographic analyses of the investigated building stone materials. The integrated and coordinated application of these non-destructive techniques allowed the creation of high-precision models of both the surface and interior of several artifacts from the Basilica of San Saturnino, the oldest church in Cagliari (Italy), dedicated to the city's patron saint. Finally, this integrated study highlighted areas of deterioration of these artifacts due to atmospheric elements such as wind and rain, and anthropogenic phenomena such as atmospheric particulate matter from traffic and other manufacturing activities.