高原寒冷地区沥青混合料冻融循环作用下劈裂性能分析

摘要

通过沥青混合料冻融循环劈裂试验,分析了冻融循环次数以及油石比对混合料劈裂性能的影响.试验得出:随着冻融循环次数的增多,沥青混合料的劈裂抗拉强度、破坏劲度模量均呈减小趋势,最初的几次冻融循环混合料性能衰减较快,经历9～15次冻融循环后性能衰减趋于平缓;冻融作用后混合料的破坏拉伸应变反而增大;油石比对沥青混合料的劈裂性能有明显影响,随着油石比的增大,冻融循环作用对劈裂性能的影响减小.结果表明,在青藏高原寒冷地区对于AC-13沥青混合料,最佳油石比为5.5％或适当增加油石比可以提高沥青混合料冻融循环作用下的劈裂性能.%Influence of freeze-thaw cycles as well as asphalt-aggregate ratio have been analyzed by means of splitting test on asphalt mixture under freeze-thaw conditions.The results showed that the splitting tension strength and failure stiffness modulus of asphalt mixture decreased as the times of freeze-thaw cycles increased,while the failure tensile strain has increased.The mixture performances attenuate in the initial freeze-thaw cycles and turn to gentle after 9～15 times of freeze-thaw cycles.The influence of asphalt-aggregate ratio has significant influence of freeze-thaw cycle on the splitting characteristics,the influence of freeze-thaw cycle on the splitting characteristics decreases as the asphalt-aggregate ratio increase.It turns out to be that applying AC-13 mixture with 5.5％OAC or larger can improve low temperature splitting characteristics of mixture under freeze-thaw conditions.The research results can provide references to the construction of asphalt pavement in cold plateau regions.