A New Ultrasonic Amplitude Tomography Approach, with Validation on Masonry Tuff Blocks

Despite sonic and ultrasonic tomography are major NDT techniques, the resolution and the capability of these tests could be substantially improved; this, especially for masonry structures. Moreover, although waves amplitude attenuation is strictly related to the internal features and to the defects, some experimental and theoretical issues obstruct practical applications of amplitude tomography for civil structures. Indeed, almost exclusively travel time tomography is employed. Here, a new approach for ultrasonic amplitude tomography called Standardized Amplitude Tomography (SAT) is proposed. This approach is based on a suitable formulation of the theoretical model to be implemented for the tomographic reconstruction of the internal features of materials and on the employ of a special experimental tool. SAT approach is primarily meant for application to masonry structures, but its principle is applicable to concrete or timber structural elements as well. The effectiveness of SAT is discussed by means of experimental tests on Apulian tuff specimens having known internal defects. The results obtained by the new SAT approach are compared to those obtained by the ordinary amplitude tomography and by the classical travel time tomography.