A procedure to detect flaws inside large size marble blocks by ultrasound

In stone and marble industry there is considerable interest in the possibility of using ultrasound diagnostic techniques for non-destructive testing of large size blocks in order to detect internal flaws such as faults, cracks and fissures. In this paper some preliminary measurements are reported in order to acquire basic knowledge of the fundamental properties of ultrasound, such as propagation velocity and attenuation, in the media here considered. We then outline a particular diagnostic procedure for obtaining a non-invasive, non-destructive quality control of blocks. Finally, the structure of a measuring set up specifically designed for in-field use is described and the experimental results are reported and discussed.