不同砂率混凝土声发射特性试验分析

Analysis of Acoustic Emission Characteristics of Concrete with Different Sand Ratios

为了深入研究不同混凝土组份的声发射特征规律,开展了不同砂率混凝土试件在单轴压缩试验下的声发射试验,综合分析砂率组分变化引起的声发射损伤特性变化.结果表明:随着期龄的增加,试件AE(声发射)波速不断增加;AE波速受砂率影响较大,随着砂率的增大,试件AE波速也越来越大.从能量角度分析损伤过程,砂率越高的混凝土试件声发射振铃计数更加活跃、累积能量更多;声发射低频率段信号40~60 kHz一直处于活跃状态.频带变化特性可作为不同砂率混凝土试件的临界破坏参考依据;砂率越大,在荷载作用下损伤演化也更为剧烈,b值下降区间提前.

In order to further study the acoustic emission characteristics of different concrete components, acoustic emission tests of concrete specimens with different sand ratios were carried out under uniaxial compression test. The change of AE damage parameters caused by the change of sand ratio is analyzed. The variation of acoustic emission damage characteristics caused by the change of and ratios was comprehensively analyzed. The results show that AE wave velocity increases with age. The wave velocity is greatly affected by the sand rate. With the increase of the sand rate, the AE wave velocity of the specimen is also increasing. The damage process is analyzed from the perspective of energy. The concrete specimens with higher sand ratio has more active acoustic emission ringing count and more accumulated energy. The low frequency acoustic emission signal of 40 ~ 60 kHz is always active. The frequency band variation characteristics can be used as a reference for the critical failure of concrete specimens with different sand ratios. Under the action of load, the damage evolution is more severe with the increase of sand ratio and the b value drops earlier.