Wu Shaopeng, Ye Yong, Li Yuanyuan, Li Chuangmin, Song Wei, Li Hechuan, Li Chao, Shu Benan, Nie Shuai
State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China.
Engineering Laboratory of Spatial Information Technology of Highway Geological Disaster Early Warning in Hunan Province, Changsha University of Science & Technology, Changsha 410114, China.
Materials (Basel). 2019 Jul 30;12(15):2424. doi: 10.3390/ma12152424.
Although huge numbers of investigations have been conducted for the ultraviolet (UV) aging of asphalt binder, research rarely focuses on the asphalt mixture. In order to evaluate the aging effect of UV radiation on the asphalt mixture, a dense grade of asphalt mixture was designated and aged by UV radiation for 7, 14 and 28 days respectively. After that, the chemical functional groups of asphalt binder were tested by Fourier transform infrared spectrometer (FTIR). The semi-circular bending strength and fatigue resistance of asphalt concrete were tested to characterize the mechanical properties of the asphalt concrete. To evaluate the self-healing effect of the macro-structure continuity of asphalt concrete intuitively, the computed tomography (CT) scanning machine was used to characterize the crack size of asphalt concrete samples both before and after self-healing. The results show that, with the increase of UV irradiation time, the relative ratios of the C=O and S=O bands' areas of recovered asphalt binder increase significantly. UV radiation can significantly weaken the mechanical and self-healing properties of asphalt mixture, making the asphalt mixture to have worse macro-structure continuity, lower failure strength and worse fatigue resistance. Moreover, the longer the UV irradiation time is, the degradation effect of UV radiation on asphalt mixture becomes more obvious.
尽管针对沥青结合料的紫外线（UV）老化已经开展了大量研究，但很少有研究聚焦于沥青混合料。为了评估紫外线辐射对沥青混合料的老化效果，设计了一种密级配沥青混合料，并分别进行7天、14天和28天的紫外线辐射老化处理。之后，采用傅里叶变换红外光谱仪（FTIR）对沥青结合料的化学官能团进行测试。通过测试沥青混凝土的半圆弯曲强度和抗疲劳性能来表征沥青混凝土的力学性能。为直观评估沥青混凝土宏观结构连续性的自愈效果，利用计算机断层扫描（CT）扫描仪对沥青混凝土试件自愈前后的裂缝尺寸进行表征。结果表明，随着紫外线照射时间的增加，再生沥青结合料中C=O和S=O波段面积的相对比例显著增加。紫外线辐射会显著削弱沥青混合料的力学性能和自愈性能，使沥青混合料的宏观结构连续性变差、破坏强度降低且抗疲劳性能变差。此外，紫外线照射时间越长，其对沥青混合料的降解作用越明显。
