温度及动水压力工况下纤维沥青碎石封层层间黏结性能

Interlayer Bonding Performance of Fiber Asphalt Chip Seal under Different Temperatures and Hydrodynamic Pressures

为解决湿热地区纤维沥青碎石封层与沥青面层层间黏结性能不足的难题,考虑温度及动水压力工况,通过层间拉拔试验及剪切试验,研究了改性乳化沥青类型、碎石岩性及粒径等因素对纤维沥青碎石封层层间黏结性能的影响.基于纤维-沥青界面及封层断裂面处的扫描电镜分析,揭示了封层层间黏结性能的增强机理.结果表明:动水-温度耦合与温度单因素作用下的封层黏结性能变化规律基本吻合;封层黏结性能的破坏形式主要为黏附性破坏,玄武岩碎石封层拉拔强度大于花岗岩碎石封层,且在动水压力作用下更为显著;3~6mm与4~8mm碎石封层的拉拔强度高于5~10mm碎石封层;动水压力为0.1~0.3MPa时,碎石封层剪切强度下降速率达到峰值;纤维均匀撒布在两层乳化沥青之间,在吸附、化学键及扩散共同作用下提升材料内聚力与黏附性,增强了纤维沥青碎石封层层间黏结性能.

To solve the problem of the deficient interlayer bonding performance between fiber asphalt chip seal and asphalt pavement in the hot and humid areas,interlayer pull-off test and shear test were carried out under different temperatures and hydrodynamic pressures,then the impact of factors such as modified asphalt emulsion type,aggregate lithology and aggregate size on the interlayer bonding performance of fiber asphalt chip seal was investigated.Based on the SEM analysis of fiber-asphalt interface and damage interface,the strengthen mechanisms of bonding performance were revealed.Laboratory test results indicate that the results of bonding performance in different hydrodynamic pressure-temperature conditions are mainly in agreement with that in the single factor of temperature;failure modes of bonding performance are mostly of adhesion type,pull-off strength of basalt fiber chip seal is higher than that of granite fiber chip seal,and it shows more significantly in the hydrodynamic pressure condition;pull-off strength of 3-6mm and 4-8mm chip seal is higher than that of 5-10mm;the descending rate of shear strength peaks under the hydrodynamic pressure of 0.1-0.3MPa;fibers are dispersed uniformly between two emulsified asphalt layers with the result that the cohesion and adhesion by the action of adsorption are enhanced,and the bonding performance of fiber asphalt chip seal are strengthened by chemical bonding and diffusion.