Actively modulated acoustic nondestructive evaluation of concrete

The need in testing concrete is not only the ability to detect large cracks or flaws but also reliably and efficiently to quantify the residual strength. Current nondestructive testing methods are capable only of discriminating high states of damage. This study lays the foundation for an evaluation method that may be significantly more sensitive than traditional nondestructive evaluation (NDE) to the damage in concrete without high dependency on testing conditions. One promising method of evaluating damage state in concrete is by frequency domain analysis of the stress waves that pass through the material. This study unveils the potential of nonlinear frequency analysis methods for concrete damage detection and evaluation using actively modulated acoustic (AMA) signals. This method actively interrogates the specimen material exaggerating the nonlinearity that exists due to microcracking and deterioration. (C) 2004 Elsevier Ltd. All rights reserved.