硬质沥青混合料的动态黏弹特性

Dynamic Viscoelastic Property of Hard Grade Asphalt Mixture

采用两种硬质沥青胶结料和粗、细两个级配设计了4种硬质沥青混合料,研究了其高温、低温、水稳定性,在此基础上,采用7个温度条件动态模量试验研究了硬质沥青混合料的动态黏弹特性,确定了基于反曲函数的黏弹模型,建立了动态模量主曲线,研究结果显示,硬质沥青混合料高温性能优异,低温性能和水稳定性均可满足现行规范的要求。在10-3~104Hz频率范围内,骨架级配混合料动态模量高于悬浮级配。基于CAM模型的黏弹分析发现,硬质沥青混合料玻璃态复数模量均表现为骨架级配的大于悬浮级配,而交叉频率均表现为悬浮级配的大于骨架级配,说明悬浮级配硬质沥青混合料低温性能优于骨架级配。

Four hard grade asphalt mixtures of 2 hard asphalt binders and 2 gradations are designed, and their high/low temperature stability and moisture stability are researched. On this basis, the dynamic modulus test at 7 temperatures is conducted to research the dynamic viscoelastic property of the hard grade asphalt mixtures. The viscoelastic models based on sigmoid function and the master curves of dynamic moduli are established. The research result indicates that （1） hard grade asphalt mixture has excellent high temperature performance, its low temperature performance and water stability can meet the requirement of current specification; （2） the dynamic moduli of coarse graded mixture is higher than that of fine graded mixture in the frequency range of 10-3 _ 104 Hz. The viscoelastic analysis based on CAM model shows that the complex moduli of the hard grade asphalt mixtures in glassy state with coarse gradation is higher than those with fine gradation, while the crossing frequencies of fine gradation are higher than those of coarse gradation, it indicates that the finer gradation is beneficial to the low temperature performance of hard grade asphalt mixture.