Study on AE characteristics of concrete with different w/c ratio under uniaxial compression

Concrete material is a three-phase composite material. Its acoustic emission (AE) characteristics are influenced by the properties of its components. The water-cement ratio has significant influence on the mechanical properties and components of concrete. To clarify the relationship between water-cement ratio and AE characteristics of concrete, in this study, AE characteristics of concrete with different water-cement ratio were discussed through parameter analysis and frequency domain analysis. A damage evaluation model of concrete was established based on AE events,cumulative AE ringing count (CR) and cumulative energy (CE).The results show that AE parameters can characterize the three-stage failure process of concrete, namely the initial stage, the stable stage and the active stage.The water-cement ratio has obvious influence on the damage process of concrete and the time distribution of AE parameters.With the development of the damage process, AE signals shift from 30 kHz to 300 kHz and higher frequencies, and the number of main frequency segments increases. On this basis, the evaluation model D of concrete compression damage based on the CR and CE was established. The tangent slope of D was used to observe the change of damage stage, which is in good agreement with the experimental results