高速公路加铺热拌超薄磨耗层级配设计研究

热拌超薄磨耗层是公路预防性养护的有效技术之一，基于某高速超薄磨耗层预防性养护工程，对不同级配进行路用性能试验研究。结果表明，不同级配混合料孔隙率随着2.36 mm筛孔通过率的增加而降低，细集料和矿粉均会填充混合料孔隙而且矿粉的填充效果为细集料的3倍。随着超薄磨耗层级配由粗变密，混合料马歇尔稳定度增加，肯塔堡飞散损失降低，疲劳寿命下降，采用矿粉作为填料的混合料性能显著优于细集料。相关性分析结果表明，超薄磨耗层混合料马歇尔稳定度，飞散损失以及疲劳性能与孔隙率存在较好的相关性，TSR结果与沥青膜厚度存在较好的相关性。超薄磨耗层的设计需要充分考虑孔隙率与沥青膜厚度指标。

Study on Gradation Design of Hot Mix Ultra-thin Friction Course on Expressway

Hot mix ultra-thin friction course is one of the effective technologies of highway preventive maintenance. The pavement performances of ultra-thin friction courses of different gradations are tested and studied based on a preventive maintenance of expressway. Results show that the porosity of mixtures at different grades decreases with the increase of 2.36-mm sieve pore passing rate. Both fine aggregates and mineral powder will fill the mixture pore and the filling effect of mineral powder is 3 times of fine aggregates. With the gradation of ultra-thin friction course from coarse to fine, the Marshall stability of mixture increases, the Cantabro flying loss decreases and the fatigue life reduces. The used mineral powder as the mixture performance of a filler is significantly better than that of fine aggregates. The correlation analysis results show that the Marshall stability, flying loss and fatigue performance of ultra-thin friction course mixture are well correlated with the porosity. TSR result is well correlated with asphalt film thickness. The indicators of porosity and asphalt film thickness should be highly considered during the design of ultra-thin friction course.