基于MMLS3试验的混合料离析对沥青路面长期高温性能的影响

Influence of Asphalt Mixture Segregation on Long-term High Temperature Performance of Asphalt Pavement Based on MMLS3 Test

利用小型加速加载设备(MMLS3)分别对吉珲高速沥青路面上面层(SMA-16)和中面层(AC-20)进行加速加载试验研究,在分析判断中、上面层沥青混合料沿横断方向的离析程度的基础上,通过室内加速加载20万次试验,研究不同施工空隙率离析及不同重复荷载作用次数对中、上面层长期高温车辙的影响规律。研究结果表明:施工空隙率离析对沥青路面长期高温性能影响显著;上面层和中面层对应重复加载次数下的车辙深度随离析程度的增加而增大,其中对中面层的影响更为显著;累积加载达到10万次后,路面结构材料内部出现了应力疲劳,重度离析试件的车辙发展出现突变,20万次时车辙变化率要高出无离析试件276%。

Using MMLS3, the authors studied the first-layer of SMA-16 and the mid-layer of AC- 20 of Jilin-Hunchun Expressway. The segregation degree of the mid-layer and first-layer pavement along the cross-sectional direction was analyzed. Indoor accelerated test to analyze the two pavement materials＇ long-term rut changing role under different segregation degrees and different times of repeated load. The result shows that segregation degree has significant influence on long-term high temperature performance of asphalt pavement. Under the same repeated load times, the rut depth o{ the first-layer and mid-layer increases with the segregation degree increasing. The influence on the mid-layer is more significant. When the cumulative load reaches 100 thousand, stress fatigue appears in the pavement material and the rut trend of the heavy segregation sample mutates. When the cumulative load reaches 200 thousand, the change rate of rut is 276% higher than that of no-segregation sample.