ABSTRACT
In homogenous concrete, free of defects, the velocity of sound is constant and in the order of 4000 m/sec. Concrete containing soil inclusions, bentonite, honeycombing etc has a lower sound propagation velocity. This means that measurements of wave speed or transit time can be used as a non destructive method of assessing the quality of buried concrete foundations. Anomalies in the concrete are indicated by a change in signal arrival time or amplitude. A typical signal is shown in Figure 2.
