Ultrasonic pulse velocity equipment is used to qualitatively locate unsound areas within concrete structures. Ultrasonic pulse velocity equipment consists of two ultrasonic transducers, a control unit, and surface couplant, as shown in Figure 1. One of the transducers acts as a transmitter and the other acts as a receiver. Ultrasonic pulse velocity is a stress-wave technique that propagates an ultrasonic wave through the material and measures the time needed for the wave to pass through. Optimal results are obtained when both sides of the structure are accessible. The wave travel time is used to infer the quality of the concrete. Shorter travel times indicate higher quality concrete and longer travel times indicate lesser quality concrete which could contain voids, cracks, and/or delaminations. In special applications, ultrasonic pulse velocity can be used to estimate the depth of fire damaged concrete or estimate the depth of cracks.
Figure 1: Ultrasonic Pulse Velocity Equipment