Fu Liuxu, Zhou Huanyun, Yuan Jing, An Weiliang, Chen Xianhua
School of Transportation, Southeast University, Nanjing 211189, China.
Broadvision Engineering Consultants, Kunming 650011, China.
Materials (Basel). 2021 Oct 9;14(20):5930. doi: 10.3390/ma14205930.
Freeze-thaw (F-T) cycling and aging effects are the main factors contributing to the deterioration of asphalt mixtures. The acoustic emission (AE) technique enables real-time detection regarding the evolution of internal damage in asphalt mixtures during the loading process. This study set out to investigate the effects of F-T cycling and aging on the damage characteristics of asphalt mixture under splitting loads. Firstly, the Marshall specimens were prepared and then exposed to various numbers of F-T cycles (one, three, five, and seven) and different durations of aging (short-term aging and long-term aging for 24, 72, 120 and 168 h), after which the specimens were loaded by means of indirect tensile (IDT) testing, and corresponding parameters were synchronously collected by the AE acquisition system during the fracture process. Finally, the energy, cumulative energy and peak frequency were selected to investigate the damage mechanisms of asphalt mixtures. The findings demonstrate that the AE parameters provided effective identification of the deterioration for all specimens in real-time, and that the F-T cycling and aging effects altered the damage characteristics of asphalt mixtures, causing early damage, exacerbating the formation of micro-cracks in the early stage, accelerating the expansion of macro-cracks and advancing the debonding between the asphalt and aggregates. The findings of this study provide further insight into the mechanism of F-T cycling and aging effects on the deterioration of asphalt mixture.
冻融（F-T）循环和老化效应是导致沥青混合料性能劣化的主要因素。声发射（AE）技术能够实时检测沥青混合料在加载过程中内部损伤的发展情况。本研究旨在探讨冻融循环和老化对劈裂荷载作用下沥青混合料损伤特性的影响。首先，制备马歇尔试件，然后使其经历不同次数的冻融循环（1次、3次、5次和7次）以及不同时长的老化（短期老化以及分别为24、72、120和168小时的长期老化），之后通过间接拉伸（IDT）试验对试件进行加载，并在断裂过程中利用AE采集系统同步采集相应参数。最后，选取能量、累积能量和峰值频率来研究沥青混合料的损伤机制。研究结果表明，AE参数能够实时有效地识别所有试件的劣化情况，并且冻融循环和老化效应改变了沥青混合料的损伤特性，导致早期损伤，加剧了早期微裂纹的形成，加速了宏观裂纹的扩展，并促使沥青与集料之间的脱粘提前发生。本研究结果为深入了解冻融循环和老化效应导致沥青混合料劣化的机制提供了进一步的见解。
