冻融循环-动水冲刷对间断级配沥青混合料特性参数影响

Influence of freeze-thaw cycles-dynamic water scouring cycles on the characteristic parameters of intermittently graded asphalt mixture

沥青路面在水、温和荷载长期作用下服役寿命明显降低.为探寻沥青混合料路用性能衰减规律,本文自主研发了沥青混合料动水冲刷模拟试验装置,对沥青混合料马歇尔试件开展多次冻融循环-动水冲刷循环作用,分析了沥青混合料特性参数变化规律,结合CT切片扫描,探寻了沥青混合料内部结构变化规律.结果表明:在冻融循环-动水冲刷循环前期,各特性参数都呈现出较快的增长或衰减;在外加动力水压作用下,沥青混合料内部吸水量会逐渐增加至饱水状态,沥青混合料试件内部的微开口孔隙会发生结构与形态的变化;经12次冻融循环-动水冲刷循环,沥青混合料的劈裂强度降幅高达65.44%.研究结果为深入了解沥青路面水损害机理提供了理论基础.

Under the long-term action of water,temperature and load,the service life of asphalt pavement is significantly reduced.In order to explore the decay law of asphalt mixture road performance,a dynamic water scour simulation test device for asphalt mixtures was independently developed.The asphalt mix Marshall specimens were subjected to multiple freeze-thaw cycles-dynamic water scouring cycles to analyze the change law of asphalt mix characteristics parameters,combined with CT slice scanning to explore the law of internal structural changes of asphalt mixes.The results show that each characteristic parameter shows a faster growth or decay in the pre-freeze-thaw cycle-dynamic water scour cycle.Under the action of applied dynamic water pressure,the internal water absorption of asphalt mixture will gradually increase to the full water state,and the micro-open pores inside the asphalt mixture specimens will undergo structural and morphological changes.The splitting strength of the asphalt mixture was reduced by up to 65.44%after 12 freeze-thaw cycles-dynamic water scouring cycles.The research results provide a theoretical basis for further understanding of the water damage mechanism of asphalt pavements.