在MTS材料试验机上进行相同尺寸的混凝土、骨料(花岗岩)、砂浆和骨料-砂浆界面4种试件的轴拉试验,采用宽频式传感器同步采集从加载到最终破坏全过程的声发射(AE)信号特征参数和波形,比较由声发射撞击累计数曲线所代表的损伤发展过程,分析声发射振幅和上升时间参数以及波形频谱所表征的不同材料声发射特征,对声发射波形的FFT频谱能量在不同频段上的分布进行统计分析,并根据声发射波形频谱图的特征形状对其进行分类,结果表明:混凝土及其三种组成材料试件在轴拉损伤破坏过程中,界面和砂浆试件损伤出现得最早;骨料试件中的短上升时间(<30μs)的撞击所占的比例最高,达到了约84％;声发射信号能量按照大小顺序主要分布在100～150kHz、200～250kHz、250～300kHz和150～200kHz 4个频段;界面试件与其他试件的不同之处在于.200～250kHz频段所集中的能量略高于250～300kHz频段;骨料试件第一主频在250～300kHz频段的撞击数量占总数的比例为35.7％,而砂浆和界面分别为25.2％和13.9％;界面试件第一主频在200～250kHz的撞击比例为16.1％.而骨料和砂浆试件分别为6.5％和4.8％.研究结论有助于进一步识别混凝土损伤断裂过程的物理机理.%Four types of specimens of concrete, aggregate ( granite) , mortar and aggregate-mortar interface are tested under uniaxial tensile loading on a MTS materials test system. Feature parameters and waveforms of acoustic emission (AE) signals during the loading process are acquired by using broadband sensors simultaneously. Comparison and statistical analysis of the AE parameters and waveform spectrums based on FFT are performed. AE hits are sorted into distinctive classes according to the shapes of their spectrums. The results indicate that the earliest appearance of damage is at the interface between aggregate and mortar, and that the percentage of hits in short rise time ( <30μs) from the aggregate specimen reaches about 84% , which is higher than the other specimens. The energies of AE signals are mainly distributed within the four frequency bands of 100～150kHz, 200～250kHz, 250～300kHz and 150～200kHz. The percentage of hits with the dominant frequency band of 250～300kHz for the aggregate specimen is about 35.7% , while for the mortar and the interface specimens are 25. 2% and 13. 9% , respectively. The percentage of hits with the dominant frequency band of 200～250kHz for the interface specimen is about 16. 1% , while for the aggregate and the mortar specimens are 6.5% and 4. 8% , respectively.
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