Influence of propagation distance on cracking and debonding acoustic emissions in externally reinforced concrete beams

摘要

Acoustic emission (AE) data from bending of externally reinforced large scale concrete beams are presented. Emissions from concrete cracking and debonding of carbon fiber reinforced polymer strip are identified in conjunction with other nondestructive testing measurements. It is shown that although the nature of AE signals differs much depending on the actual source, any discrimination between them will not be feasible if the data are not adequately treated as to their propagation path. The reason is that frequency and other waveform characteristics of cracking AE signals start to resemble debonding ones from the external reinforcement as they propagate for additional distance. The phenomenon is verified and strategies to overcome are discussed in order to enable application of simple parameter-based criteria developed in laboratory for the crack mode characterization in large structures.