Study of damage evolution in concrete with different initial defects under uniaxial compression by acoustic emission

It is important to evaluate internal damage in concrete under load conditions in order to evaluate its stability and usability for building applications. In this study, uniaxial compression was applied to concrete specimens with initial defects and the internal damage of the concrete was monitored by acoustic emission (AE) technology in real time to study the damage process and mechanism. The mechanical properties of concrete specimens with different initial defects were determined and the cumulative impact count of AE was recorded. The response characteristics of AE in the process of concrete compression and damage were obtained. According to analysis of the influence of initial defects on the Kaiser effect and since the irreversibility of the AE process is related to the degree of damage in the material under preload, it was determined that initial defects will aggravate internal damage under the same load level. Based on the statistics and analysis of the Weibull cumulative function, the correlation between AE parameters and damage variables was assessed.