flaw detection in concrete structures by advanced nondestructive test method impact echo

The impact echo methodisatechnique for flaw detection in concrete it is based on monitoring the surface motion resulting from a short duration mechanical impact the method overcomes many of the barriers associated with flaw detection in concrete based on ultrasonic methods the purpose of this paper is to provide an overview of the technique and to discuss the important parameters involved in this type of testing one of the dey features of the method is the transformation of the recorded time domain waveform of the surface motion into the frequency domain the impact gives rise to modes of vibration and the frequency of these modes is related to the geometry of the test object and the presence of flaws.