盐冻融循环对沥青混合料低温性能的影响

Impact of Freeze Thaw Cycles with Salt on Low Temperature Properties of Asphalt Mixture

关键词:  道路工程  沥青混合料  低温性能  盐冻融  应变能密度

Key words:  road engineering  asphalt mixture  low temperature property  freeze thaw with salt  strain energy density

摘要:

采用低温弯曲试验，以最大弯拉应变比、弯曲劲度模量和应变能密度等指标分析了盐冻融循环条件下沥青混合料低温性能的衰变规律，研究了掺加纤维等添加剂后，在盐冻融循环条件下沥青混合料低温性能的改善效果.结果表明：沥青混合料经盐冻融循环后，其最大弯拉应变比、应变能密度显著减小，弯曲劲度模量增大；随着盐冻融循环次数的增加，各指标变化幅度逐渐减小；盐溶液质量分数越高、冻融温度越低，对沥青混合料的低温性能影响也越大；应变能密度与盐冻融循环次数呈指数函数变化；玄武岩纤维对盐冻融循环条件下沥青混合料低温性能的改善效果较好.

Abstract:

Through flexural test at low temperature， the decay law of the low temperature performance of asphalt mixture under freeze thaw cycles with salt was analyzed by maximum flexural tensile strain， flexural stiffness modulus and strain energy density. The effects of fiber addition and the other modifiers on the low temperature performance of mixture were investigated. The results show that maximum flexural tensile strain and strain energy density of asphalt mixture decrease rapidly after freeze thaw cycles with salt， while flexural stiffness modulus increases. With increasing the number of freeze thaw cycles， the variation degree decreases gradually. The higher the mass fraction of salt in the solution and the lower the change of freeze thaw temperature， the larger the influence on strain energy density of asphalt mixture. The variation show exponential function between strain energy density of the mixture and the numbers of the freeze thaw cycles with salt. The improvement of basalt fiber on the low temperature performance of asphalt mixture is very significant under the condition of freeze thaw cycles with salt.