Slant-Stack analysis for the estimation of a marble degradation profile
Résumé
Ultrasonic techniques are increasingly used in various fields such as mining, geotechnical, civil engineering, because they are non-destructive and easy to apply. These techniques are usually employed both in situ and in laboratory conditions to characterize and determine the dynamic and physical properties of rocks. In cultural heritage, the characterization of marble statue by acoustic wave is a wellknown non-destructive method. This paper undertakes a study of the Carrara marble that composes the statues exposed in the Château de Versailles gardens, in order to better understand the processes of deterioration affecting them. For this, a plate of Carrara marble is artificially aged through heating/cooling thermal cycles performed on one face of the samples. A Rayleigh wave is generated by a 1 MHz central frequency contact transducer exited by a voltage pulse. A laser vibrometry method is used to detect the Rayleigh wave propagation on the depth sample. In order to understand how the degradation and nonhomogeneity and Rayleigh velocity vary through depth, Slant Stack (SS) transform was used. This analysis is a particular case of the Radon Transform (TR). The results show a uniform vibration behavior of non-degraded sample and highlight three zones with different state of degradation in the altered marble sample. The extraction of relevant parameters using this analysis is promising for the characterization of marble and following up its weathering.