盐冻循环条件下SBS改性沥青砂浆的力学性能分析

The mechanical properties analysis of SBS modified asphalt mortar under salt freezing cycle

在寒冷地区,冬季路面极易出现积雪结冰现象,常使用融雪盐对路面进行融雪除冰,融雪盐的使用会对沥青混合料产生侵蚀。沥青砂浆作为沥青混凝土材料的重要组成部分,在力学性能方面发挥了极其重要的作用。对SBS改性沥青盐冻循环前后的三大指标(针入度、软化点和延度)进行了测试,对经历不同盐冻循环的沥青砂浆试件进行单轴压缩蠕变实验,并通过扫描电镜(SEM)研究其微观结构的变化。结果表明,冻融循环和荷载应力会造成沥青砂浆力学性能的下降,因此在昼夜温差较大的北方寒冷地区的冬季应尽量限制重载车辆的通行量以及融雪盐的用量,以减少对路面结构的损坏。

De-icing salt was often used when the road was covered by snow and ice in cold area,which would cause erosion to asphalt mixture. Asphalt mortar,as an important part of asphalt pavement materials,plays an extremely important role in the mechanical properties of asphalt concrete. The three routine indicators( penetration,softening point and ductility) of the SBS modified asphalt was tested before and after the salt freezing. Uniaxial compression creep test of SBS modified asphalt mortar specimens were conducted after different salt freezing cycles. And the SEM( scanning electron microscope) was used to observe the microstructure of SBS modified asphalt mortar. The analysis results showed that the freeze-thaw cycle and load stress would cause the loss of mechanical properties of SBS modified asphalt mortar. So It is necessary to restrict traffic and overloading and the use of de-icing salt in cold area,in order to reduce the damage of pavement structure.