Crack classification in concrete based on acoustic emission

The fracture mode of cracking in concrete is normally changing from tensile mode to shear mode at impending failure. As for crack classification in concrete by acoustic emission (AE) techniques, two crack classification methods have been carried out. One of them is parameter-based method (parameter analysis) which has been carried out by employing two parameters of the average frequency and the RA value. The proportion of these two parameters, however, has not been determined yet. The other crack classification is simplified Green's functions for moment tensor analysis (SiGMA) procedure which is known as signal-based method. The SiGMA analysis is based on the generalized theory of AE, while the parameter analysis results from an empirical relation. Therefore, an optimal proportion of the parameter analysis is in great demand. In this study, these crack classification methods are compared and discussed from results of three types of concrete failure tests. As a result, ratios of the shear crack which are identified by SIGMA analysis are good agreement with those by parameter analysis in the case that the proportion of the RA value and the average frequency is set to 1-200. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.