Title: Laboratory and Field Studies of the Impact-Echo Method for Flaw Detection in Concrete

Author(s): M. Sansalone and N. J. Carino

Publication: Symposium Paper

Volume: 112

Issue:

Appears on pages(s): 1-20

Keywords: concretes; concrete slabs; impact; nondestructive tests; ultrasonic tests; voids; General

DOI: 10.14359/3688

Date: 1/1/1989

Abstract:
A nondestructive test method has been developed for locating defects in concrete. The technique is referred to as the impact-echo method and is based on monitoring surface displacements resulting from the interactions of transient stress waves with internal discontinuities. Paper describes the technique and presents results of laboratory studies designed to evaluate the capabilities of the method. These laboratory studies were carried out on 500 mm thick slabs that contained a variety of artificial flaws embedded at known locations. Frequency analysis of recorded time-domain waveforms is explained and shown to be a quick and simple signal processing technique. Finally, results are presented from a field study in which the impact-echo method was used to investigate a 150 mm thick slab believed to contain voids.