The influence law of concrete aggregate particle size on acoustic emission wave attenuation

Elastic waves have different attenuation laws when propagating in various materials, which is one of the important challenges in the application of non-destructive testing methods, such as acoustic emission (AE) technology in geotechnical engineering. The study presented in this paper investigated the influence mechanism of concrete composition materials and parameters on the propagation law of elastic waves using concrete specimens produced in six different particle sizes of sand or gravel. The burst AE signal was generated through the lead-breaking experiment, and ceramic piezoelectric sensors were used to record the signal waveform at different propagation distances. Through parameter analysis, spectrum analysis, and pattern recognition techniques, the influence of the concrete aggregate particle size on AE wave propagation and attenuation was revealed. The results show that the attenuation of elastic wave amplitude, energy spectral density, and frequency all were positively correlated with the aggregate particle size, and the elastic wave spectrum center of gravity generally decreased with the propagation distance. The ring count gradually decreased with the propagation distance, and the specimens with a larger aggregate particle size underwent a relatively faster ring count attenuation rate. The rise time increased rapidly with the propagation of the elastic wave, and the specimens with a larger aggregate particle size experienced a relatively rapid increase in rise time. In addition, in the feature spaces of ring count-amplitude and rise time-amplitude, the size of aggregate has an obvious influence on the distribution of these feature vector.