APPLICATION OF NON DESTRUCTIVE ULTRASONIC TECHNIQUES, AS METHODOLOGY FOR THE ANALYSIS OF THE CONSERVATION STATUS OF BUILDING MATERIALS IN MONUMENTAL STRUCTURES

Some examples of application of ultrasonic methods were chosen, as a methodological approach, in different test areas located in Dion archeaological site (Northern Greece) and Cagliari historical city center (Southern Sardinia – Italy). The study on the above mentioned sites was focused on the application of ultrasonic techniques in the low frequency range (24-54 kHz), with the aim to verify the conservation status of the building materials of the monumental structures, by means of the study of the longitudinal ultrasonic pulses propagation. Compressional velocity has been related to the physical, textural and mineralogical-petrographic features of the investigated materials, to correlate their intrinsic properties with the elastic ones. On the base of the laboratory ultrasonic measurements, in situ investigations have been performed to identify the areas affected by degradation, quantify the intensity of weathering and monitoring its evolution.