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该文提出用声发射(Acoustic Emission,简称AE)来描述沥青混凝土中损伤积累和强度恢复特性。公称最大粒径为19mm的沥青混凝土在20℃下进行一系列的单轴拉伸循环试验,分有休息期和无休息期两种情况。在疲劳试验中,包括发射计数在内的AE关键参数由连接到高150mm、直径75mm的圆筒试样中间的两个压电式传感器获取。试验结果表明:1)累计AE能量和AE计数不仅可用于评价疲劳损伤的形成和扩展,而且可量化休息期对沥青混凝土性能的有益性;2)分析频率-振幅可知,裂缝形成与高频率时AE振幅峰值有很高的相关性,而休息期的愈合情况最好用低频率时AE振幅峰值来表述;3)Kaiser效应不适用于沥青混凝土的疲劳问题。
In this paper, acoustic emission (Acoustic Emission, AE for short) is proposed to describe the damage accumulation and strength recovery characteristics of asphalt concrete. Asphalt concrete with a nominal maximum size of 19 mm was subjected to a series of uniaxial tension cycling tests at 20 ° C, with and without breaks. In the fatigue test, the key AE parameters including emission counts were taken from two piezoelectric transducers connected to the middle of a 150 mm diameter, 75 mm diameter cylinder. The results show that: 1) The accumulated AE energy and AE count can not only be used to evaluate the formation and propagation of fatigue damage, but also to quantify the beneficial effect of rest period on the performance of asphalt concrete; 2) Analyzing the frequency-amplitude, AE amplitude peak has a high correlation, and resting healing is best expressed as the AE amplitude peak at low frequency; 3) Kaiser effect is not suitable for asphalt concrete fatigue problems.