Impact-echo. New generation of nondestructive in-situ test systems for concrete structures

The paper evaluates the possibilities of using the Impact-Echo method for nondestructive examination of concrete structures. The general principles of this technique are presented, as well. It was shown that spectrum analysis based on Fast Fourier Transformation offers a powerful tool for the evaluation of experimental data. This has been discussed in the framework of "in-situ" test results, whereby particular attention is to a further outlook on practical engineering applications. The "in-situ" investigations were focused on the determination of the thickness of a solid concrete plate of which only one side is accessible. Further, voids and delaminations existing in such a plate were localized. Finally, the use of the method for checking the quality of injected cable ducts has been shown.