Calibration of sonic pulse velocity tests for detection of variable conditions in masonry walls

Sonic pulse velocity is a non-destructive method used for diagnosing existing masonry and evaluating the effectiveness of interventions. A new comparative study is presented here, aimed at checking the reliability of the method in detecting inhomogeneities in order to qualify various masonry conditions, according to common practice and up-to-date tools, for both on-site testing and data handling. Four research groups applied direct and tomographic sonic velocity tests on three full-size wall specimens representing existing masonry types. The surface wave method was also applied to one of the specimens, to compare various outputs of elastic wave transmission. The panels incorporated various flaws and inclusions and were consolidated by grout injections. Each research unit applied its own acquisition systems and processing methods before and after panel consolidation. The results confirmed the ability of sonic pulse velocity tests in detecting large inclusions and significant variations in compactness, and provided quantitative reference values for materials and conditions. The research provided directions for further optimization of sonic waves transmission test application in already existing masonry constructions.