Applications of Sonic Tests to Masonry Elements: Influence of Joints on the Propagation Velocity of Elastic Waves

The authors applied sonic tests to study the propagation of sonic waves through stone masonry walls. In particular, tests were made to study the effect of the joints and the influence of the characteristics of the stones surface, rough or smooth, on the measurement of the sonic velocities on granite masonry specimens. A series of direct, indirect, and impact echo sonic tests were performed on single stones and on columns of stones with dry and mortar joints to obtain P - and R -wave velocities. The results allowed a better understanding of the influence of the stones characteristics and the samples geometries, namely the number of joints, to the global response of the masonry to the propagation of sonic waves. This study also allowed verifying the complementarity of the different sonic test configurations and the interest to cross information from more than one technique to obtain more reliable information. Finally, significant results were also achieved concerning the relationship between the parameters obtained for P and R waves.