不同胶粉掺量下橡胶沥青混合料路用性能分析

Road Performance Analysis of Rubber Asphalt Mixture under Different Rubber Powder Dosage

为研究不同胶粉掺量下橡胶沥青混合料的路用性能,通过在70#A级基质沥青中掺加不同质量胶粉,利用沥青激光回弹试验、沥青接触角试验分析了沥青PG(performance grade)等级以及沥青胶结料与集料之间的黏附特征,确定了橡胶沥青路面结构上、中、下面层的最佳胶粉掺量(即上面层SMA-13添加30%,中面层AC-20添加40%,下面层AC-25添加50%);通过对不同胶粉掺量橡胶沥青混合料的汉堡车辙试验、低温弯曲抗裂试验及直接剪切试验等力学性能研究得到:胶粉的掺入可增强沥青胶结料与集料间的内聚力,使沥青混合料的塑性变形能力变强,有效改善了橡胶沥青混合料不同结构层的水稳定性和高温抗车辙能力,提高了橡胶沥青混合料的抗裂性能和抗疲劳性能。结合工程实例,借用三维雷达检测系统,评价了现场橡胶混合料沥青路面结构层摊铺的整体性和材料厚的均匀性等道路内部状况;通过现场路面取芯后CT扫描,获取了现场路面结构的集料-空隙三维空间分布情况,得到了胶粉的加入能促进沥青胶结料与集料间的分子运动,有效改善沥青混合料的孔隙分布情况,使路面内部材料更加均匀分布,充分发挥橡胶沥青路面优良的路用性能。

In order to study the road performance of rubber-asphalt mixture with different rubber powder content,in this paper,by adding different quality rubber powder to 70#A grade base asphalt,the asphalt PG(Performance Grade)grade and the adhesion characteristics between asphalt binder and aggregate were analyzed by asphalt laser rebound test and asphalt contact angle test,determine the optimal rubber powder content of the upper,middle and lower layers of the rubber asphalt pavement structure(30%SMA-13 for the upper layer,40%for the middle layer AC-20 and 50%for the lower layer AC-25).Through the research on the mechanical properties of the rubber-asphalt mixture with different rubber powder contents,such as the Hamburg rutting test,the low-temperature bending crack resistance test and the direct shear test,the following results were obtained.The addition of rubber powder can enhance the cohesion between the asphalt binder and aggregate,make the plastic deformation ability of the asphalt mixture stronger,effectively improve the water stability and high temperature rutting resistance of different structural layers of rubber-asphalt mixture,improve the crack resistance and fatigue resistance of rubber-asphalt mixture.Combined with engineering examples,borrowing the three-dimensional radar detection system,the internal conditions of the road,such as the integrity of the paving of the rubber mixture asphalt pavement structure layer and the uniformity of the material thickness,were evaluated.Through the on-site road coring and CT scanning,the three-dimensional spatial distribution of aggregates and pores of the on-site pavement structure was obtained,the addition of rubber powder can promote the molecular movement between asphalt binder and aggregate,effectively improve the pore distribution of asphalt mixture,make the material inside the pavement more evenly distributed,give full play to the excellent road performance of rubber asphalt pavement.