基于抗车辙性能的长大纵坡沥青混合料设计

针对沥青路面长大纵坡路段车辙病害比较突出的现象，为最大限度降低路面的早期破坏，提高耐久性，以沥青混凝土AC-20为基础，通过对矿料级配进行优化设计，得到了一种抗永久变形能力更强的紧密骨架密实结构；选取BMF（北美孚）和浙江石金GBF两种玄武岩纤维，分别采用掺量0．2％、0．3％和0．4％进行车辙试验，分析不同纤维掺量对沥青混合料高温抗变形能力的改善效果。研究结果表明：优化设计后的SAC粗集料断级配是一种抗高温永久变形能力很强的矿料级配；玄武岩纤维沥青混合料的动稳定度得到提高，当纤维掺量在0．2％～0．3％时增长率比较快，掺量超过0．3％时增长率开始下降；AC_20沥青混合料玄武岩纤维BMF最佳掺量为0．35％，GBF最佳掺量为0．31％。研究成果可为长大纵坡路段沥青路面设计提供参考。

Asphalt mixture design on long steep asphalt pavement based on the rutting resistance performance

Aiming at the prominent phenomenon of rutting on long steep asphalt pavement, we optimized the design of mineral ag- gregate gradation based on asphalt concrete AC-20 in order to minimize the early road damage and improve the durability, and ob- tained a closely skeleton dense structure that had a stronger resistance to permanent deformation. Two kinds of basalt fibers were selected： BMF and GBF with dosages of 0.2% ,0.3% and 0.4% for rutting test respectively. The improvement on resistance to permanent deformation of asphalt mixture at high temperatures with different fiber contents was analyzed. The results showed that： the optimization design of coarse aggregate gap gradation SAC is a kind of mineral aggregate gradation which has great capa- bility of resistance to permanent deformation at high temperatures. Dynamic stability of basalt fiber asphalt mixture is improved, and when the content of fiber ranges from 0. 2 % to 0. 3 %, the growth rate is fast ~ when the content exceeds 0. 3 %, the growth rate begins to decline. The optimum mix amount of basalt fiber used in the AC-20 asphalt mixture is 0. 35 ~ for BMF and 0. 31% for GBF. Our study provides reference for asphalt mixture design on long steep asphalt pavement.