高铁防水封闭层沥青混凝土冻融损伤演化模型

Freeze-Thaw Damage Evolution Model of Asphalt Concrete for Waterproofing Layer in High-Speed Railways

为研究高速铁路防水封闭层用沥青混凝土(简称铁路沥青混凝土)的冻融损伤演化,制备了选用不同沥青和不同目标级配的4种聚合物复合改性铁路沥青混凝土,分析重复冻融循环作用下多温域宏观力学性能的劣化规律.构建针对冻融损伤演化模型,并对反复冻融循环作用下的损伤度进行计算.研究发现:4种铁路沥青混凝土在10次冻融循环作用后,各项力学性能指标的残留率均在80%以上;低温断裂能指标对冻融循环次数的增加最为敏感,更能及时反映铁路沥青混凝土的力学性能劣化;基于统计可靠度理论构建的铁路沥青混凝土冻融损伤演化模型的拟合优度值均接近0.99.

The freeze-thaw damage evolution of asphalt concrete for waterproofing layer in high-speed railways(shorted as railway asphalt concrete)was investigated.Four kinds of composite polymerized railway asphalt concrete were prepared with different asphalt binders and aggregate gradations,and the deterioration of macro mechanical properties in multiple temperature domains under repeated freeze-thaw cycles was evaluated.Models of freeze-thaw damage evolution for railway asphalt concrete were constructed,and the damage degree under the action of repeated freeze-thaw cycles was calculated.The results show that the retained rate of mechanical properties of the four kinds of railway asphalt concrete is still above 80%after 10 freeze-thaw cycles.The low-temperature fracture energy index is the most sensitive to freeze-thaw cycles,which can timely reflect the deterioration of mechanical properties of railway asphalt concrete.The goodness of fit of all freeze-thaw damage evolution models for railway asphalt concrete that are constructed through statistical reliability theory is nearly 0.99.