Damage Evaluation of Concrete Test Specimens Related to Failure Analysis

This paper shows how, from previously reported results and through a specific test (compaction tension test), the acoustic emission process may have access to an evaluation of the concrete damage. It also shows its evolution during the test. The problem of failure analysis is discussed, as well as the modeling of concrete behavior. The details of the test are described. It is shown how the acoustic emission can contribute to the understanding of this problem. The damage is located by the differences in the times of arrival of the acoustic emission signals from a single damage mechanism detected by an array of transducers surrounding the zone to be evaluated. The procedure makes it possible to monitor the evolution of the damage zone in the course of the test in real time. The degree of damage is then evaluated by filtering the signals according to amplitude. Acoustic emission processing may then be used to distinguish 3 damage zones: a microcracked zone, a macrocracked zone and a zone that may be regarded as an open crack. Each zone is characterized by a degree of damage quantified in the previous step.