Sonic Pulse Velocity tests
Sonic tests return the velocity of propagation of mechanical sonic waves through the investigated wall section. These tests provide indications of qualitative nature (quantitative if carried out in a comparative manner, for example to identify singular situations of repetitive elements) on the masonry density/soundness and on the presence of cavities, cracks or heterogeneity intercepted along the transmission path of the wave. The sonic investigation technique is based on generation of sonic pulses with frequencies in the field of mechanical noise (20-20000 Hz). The sonic wave is generated on the wall surface by hitting with an instrumented hammer, and it is then received by a sensor (piezoelectric accelerometer) located in a different part of the structure, generally in the opposite face of the wall.
Reference standards: ASTM C597–16; RILEM TC 127-MS.D.1.