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针对寒区道路工程中的沥青路面冻融受荷损伤问题,借助细观损伤力学和宏观统计随机损伤模型,建立了冻融与荷载耦合作用下的沥青混合料损伤本构关系和损伤演化方程;探讨了冻融循环次数、应变和油石比影响下的沥青混合料冻融受荷损伤劣化机理。研究表明:冻融循环疲劳损伤累积和荷载作用于带有微缺陷粗集料界面附近产生的应力集中加剧了沥青混合料总损伤劣化程度。冻融循环20次之后,损伤度变化不大,基本趋于恒定;相同损伤程度时,应变值随冻融次数的增加而减小。油石比对总损伤影响显著,当油石比相对较小时,以冻融破坏为主;当油石比较大时,以受荷破损为主。研究成果可为寒区沥青路面抗冻设计、性能评价及养护维修时机选择提供参考。
Aimed at the problem of freezing and thawing on asphalt pavement in cold area, the damage constitutive equation and damage evolution equation of asphalt mixture under the coupling of freezing and thawing and loading are established by means of mesoscopic damage mechanics and macro statistical random damage model. The degradation mechanism of freeze-thaw stress of asphalt mixture under the influence of freeze-thaw cycles, strain and ratio of oil-rock is discussed. The results show that the fatigue damage accumulation and the load effect of freeze-thaw cycles on the stress concentration near the micro-defect coarse aggregate interface aggravate the total damage degree of the asphalt mixture. After 20 cycles of freeze-thaw cycles, the degree of damage did not change much and remained basically constant. With the same degree of damage, the strain value decreased with the increase of the number of freeze-thaw cycles. The ratio of oil to stone has a significant effect on the total damage. When the ratio of oil to stone is relatively small, it is mainly caused by freeze-thaw failure. When the oilstone is relatively large, the damage is dominated by the load. The research results can provide references for frost resistance design of asphalt pavement in cold region, performance evaluation and timing of maintenance and repair.