关键词: 盐冻循环;扫描电子显微镜(SEM);SBS改性沥青;SBS改性沥青混合料;低温性能

Abstract: Deicing salt are offen used to melt ice in roads of cold regions,while asphalt pavement is easy to be damaged by salt freezing cycle.The scanning electron microscope(SEM),bending beam rheometer (BBR)and universal testing machine(UTM-100)were used to analyze the microstructure and low temperature creep performance of styrene-butadiene-styrene tri-block copolymer(SBS)modified asphalt and its mixture before and after salt freezing cycle.The test results indicate that it has great change on microstructure of asphalt and asphalt mixture after freeze-thaw cycle,the salt crystal appear on the surface of the asphalt and its mixture can damage the structure of asphalt film and the compactness of mixture;the water freezing cycle have a great influence on the low temperature performance of asphalt and mixture; the low-temperature cracking resistance of SBS modified asphalt reduces gradually with the decrease of temperature after freeze-thaw cycles; the low concentration of deicing salt can maintain the low temperature anti-cracking performance of SBS modified asphalt and its mixture to a certain extent;the low temperature performance of SBS modified asphalt and its mixture will be reduced by increasing of the number of salt freezing cycles.

Key words: salt freezing cycle;scanning electron microscope(SEM);SBS modified asphalt;SBS modified asphalt mixture;low temperature performance