冻融循环对沥青-集料界面相力学性能的影响

Effect of Freeze-Thaw Cycle on Mechanical Properties of Asphalt-Aggregate Interface Phase

冻融循环损伤是季冻区沥青路面的早期主要病害,冻融损伤主要集中在沥青-集料界面相,而目前关于冻融损伤的研究对象以沥青混合料为主。本工作针对沥青-集料界面相开展冻融损伤实验研究,制备了集料-沥青-集料“三明治”试件,对其进行多次冻融循环处理,然后对冻融循环后的试件进行剪切实验和拉拔实验,分析冻融循环与其剪切强度、拉拔强度及断裂能的关系,探索冻融循环对沥青-集料界面相力学行为的影响机制。结果表明,随着冻融循环次数的增加,试件的剪切强度与拉拔强度呈下降的趋势,初期下降快,冻融循环15次后数值趋于稳定;在相同冻融循环次数下,SBS改性沥青-集料系统的剪切、拉拔强度衰减率均高于基质沥青;随冻融循环次数的增加,拉拔实验试件断裂面集料裸露的面积逐渐增大,即界面相粘附失效占比逐渐增大。冻融循环对断裂能的影响规律与对强度的影响规律相似。

Freeze-thaw cycle damage is the main early disease of asphalt pavement in seasonal freezing areas.The freeze-thaw damage is mainly concentrated in the asphalt-aggregate interface phase.At present,the research object of freeze-thaw damage is mainly asphalt mixture.This work carries out freeze-thaw damage experimental research on the asphalt aggregate interface phase.The‘sandwich’specimens of aggregate-asphalt-aggregate were prepared and treated with multiple freeze-thaw cycles.The shear and pull-off experiments were carried out on the specimens after freeze-thaw cycles.The relationship between freeze-thaw cycles and shear strength,pull-off strength and fracture energy was analyzed,and the influence mechanism of freeze-thaw cycles on the mechanical behavior of asphalt-aggregate interface phase was explored.The results show that with the increase of the number of freeze-thaw cycles,the shear strength and pull-off strength of the specimens show a downward trend,the initial decline is fast,and the value tends to be stable after 15 freeze-thaw cycles;under the same freeze-thaw cycles,the shear and pull-off strength attenuation rates of SBS modified asphalt-aggregate system are higher than those of matrix asphalt.With the increase of freeze-thaw cycles,the proportion of the fracture surface to the pull-off surface increases gradually.The effect of freeze-thaw cycle on fracture energy is similar to that on strength.