Xu Yinshan, Jiang Yingjun, Xue Jinshun, Ren Jiaolong
School of Highway, Chang'an University, Xi'an 710064, Shaanxi, China.
Zhejiang Scientific Research Institute of Transport, Hangzhou 310039, Zhejiang, China.
Materials (Basel). 2019 Aug 22;12(17):2675. doi: 10.3390/ma12172675.
The low-temperature crack of asphalt concrete is considered to be one of the main deteriorations in asphalt pavements. However, there have been few studies on the composite effects of the aggregate characteristics and fracturing modes on the low-temperature cracking of asphalt concrete. Hence, the edge cracked semi-circular bend tests and the discrete element modeling approaches are combined to investigate the effect of the aggregate contents, aggregate morphological features and aggregate distributions on the fracture behavior of asphalt concrete in different fracturing modes at different temperatures. The results show that the fracture toughness and the crack extended time reduce with the increasing aggregate orientation and flatness and the decreased aggregate content. The effect of aggregate flatness is nonlinear and its reduction trend grows gradually with the increasing flatness. The total number of failed contacts is reduced with the increasing aggregate orientation and flatness, particularly at 10 °C. The number of failed contacts that occurred in the aggregate-mastic interface in quasi mode II fracturing is slightly higher than that in other fracturing modes. The aggregate distribution in the crack initiation zone greatly influenced the crack resistance, particularly at 10 °C. The research is beneficial to better understanding the fracture mechanisms of asphalt concrete at low-temperature.
沥青混凝土的低温裂缝被认为是沥青路面的主要病害之一。然而，关于集料特性和断裂模式对沥青混凝土低温开裂的复合影响的研究很少。因此，将边缘开裂半圆弯曲试验和离散元建模方法相结合，研究了集料含量、集料形态特征和集料分布在不同温度下不同断裂模式下对沥青混凝土断裂行为的影响。结果表明，断裂韧性和裂纹扩展时间随着集料取向和扁平度的增加以及集料含量的减少而降低。集料扁平度的影响是非线性的，其降低趋势随着扁平度的增加而逐渐增大。随着集料取向和扁平度的增加，失效接触总数减少，特别是在10℃时。准Ⅱ型断裂中集料-胶结料界面发生的失效接触数略高于其他断裂模式。裂纹起始区的集料分布对抗裂性有很大影响，特别是在10℃时。该研究有助于更好地理解沥青混凝土在低温下的断裂机理。
