Ultrasonic concrete tester or Ultrasonic Pulse velocity tester (UPV) is a fully portable instrument for assessing the strength of concrete either in situ or precast and is used to check the quality of concrete also defects within concrete by passing ultrasonic waves through the concrete.
A pulse of longitudinal vibrations is produced by an electro-acoustical transducer held in contact with one surface of the concrete under test. After traversing a known path length in the concrete, the pulse of vibrations is converted into an electrical signal by a second transducer and electronic timing circuits enable the transit time of the pulse to be measured.