Publication Date:
2020-05-19
Description:
The need to integrate different non invasive geophysical datasets for an effective diagnostic process of the stone
materials of cultural heritage buildings is due to the complexity of the intrinsic characteristics of the different types
of stones and of their degradation process. Consequently integration between different geophysical techniques is
required for the characterization of stone building materials. In order to perform the diagnostic process by different
non-invasive techniques thus interpreting in a realistic way the different geophysical parameters, it is necessary
to link the petrophysical characteristics of stones with the geophysical ones. In this study the complementary
application of three different non invasive techniques (terrestrial laser scanner (TLS), infrared thermography and
ultrasonic surface and tomography measurements) was carried out to analyse the conservation state and quality of
the carbonate building materials of three inner columns of the old precious church of San Lorenzo in the historical
city center of Cagliari (Sardinia). In previous works (Casula et al., 2009; Fais et al., 2015), especially the integrated
application of TLS and ultrasonic techniques has been demonstrated to represent a powerful tool in evaluating
the quality of the stone building materials by solving or limiting the uncertainties typical of all indirect methods.
Thanks to the terrestrial laser scanner (TLS) technique it was possible to 3D model the investigated columns and
their surface geometrical anomalies. The TLS measurements were complemented by several ultrasonic in situ and
laboratory tests in the 24kHz - 54kHz range. The ultrasonic parameters, especially longitudinal and transversal velocities,
allow to recover information on materials related with mechanical properties. A good correlation between
TLS surface geometrical anomalies and the ultrasonic velocity ones is evident at the surface and in shallow parts
of the investigated architectural elements. To calibrate the geophysical results and provide reliable data for the
interpretation, the petrophysical properties (porosity, density, water absorption) and petrographical characteristics
(especially texture) of the carbonate building materials under study were examined. By combining petrographical,
petrophysical, terrestrial laser scanner and ultrasonic techniques, a consistent diagnostic process of the carbonate
building materials can be achieved to detect the presence of defects, fissures, fractures, weathering process or
compositional variations. The above diagnostic process is very useful also to evaluate the behavior of the carbonate
building materials, facilitating the planning of urgent and long-term conservation programs and in time monitoring.
Description:
Copernicus Meetings
Description:
Published
Description:
Vienna | Austria | 23–28 April 2017
Description:
5T. Sismologia, geofisica e geologia per l'ingegneria sismica
Keywords:
diagnostic process
;
stone materials
;
cultural heritage buildings
;
non-invasive techniques
;
5T. Sismologia, Geofisica e Geologia per l’Ingegneria Sismica
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
Conference paper
Permalink
