高强混凝土单轴压缩声发射频率特征试验研究

为研究高强混凝土破裂前声发射信号的频率特征,对C60、C70、C80高强混凝土试件进行单轴压缩下的高、低频双通道声发射试验,得到破裂过程的力学参数和声发射参数,探求高强混凝土不同加载阶段声发射信号频率的分布特征。研究表明,三种高强混凝土在峰值应力前,高、低频通道声发射信号均集中在特定的频段内;临近峰值应力时,高、低频通道的声发射信号频率向低频段移动,同时优势频段内的频率趋于分散,这可作为预测高强混凝土破坏的前兆信息。

Experimental study on the acoustic emission frequency characteristics of the process of high-strength concrete under uniaxial compression

To study the characteristics of acoustic emission signals frequency of high-strength concrete before burst, for C60, C70, C80 high-strength concrete specimens, high and low frequency two-channel acoustic emission tests were done under uniaxial compression. During the whole testing process, the high-frequency and low-frequency dual-channel acoustic emission parameters have been obtained together with the mechanical parameters corresponding to the concrete compression test. Then acoustic emission characteristics at different loading phases and its peak frequency distributions just before the peak stress of high-strength concrete have been studied. Results show that at different loading stages of compression of concrete specimens, significant differences exist in the ring down counts and energy of acoustic emission. The same findings have been observed for the three high strength concrete specimens, that is in front of peak stress, acoustic emission signals obtained by the high-frequency channel (150 kHz) were concentrated in 47?78 kHz and 141?171 kHz frequency bands, whereas acoustic emission signals obtained by low frequency channel (60 kHz) have been concentrated in 32?62 kHz and 79-109 kHz frequency bands. When the concrete specimens approach the peak stress, the frequency of acoustic emission signals of high-frequency and low-frequency channels moved to a lower frequency band, and this can be used to predict the destruction of high-strength concretes.