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利用原子力显微镜(AFM)、动态剪切流变仪(DSR)和弯曲梁流变仪(BBR)对冻融循环前后的基质沥青和苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SBS)改性沥青进行了微观结构观测和高低温性能测试。试验结果表明:经冻融循环后,沥青“蜂形”结构的数量和尺寸出现不同变化,基质沥青中沥青质含量增加且分散状况变差,SBS改性剂三维网状结构遭到破坏;基质沥青的高温性能有所提升,抗疲劳性能降低,SBS改性沥青的高温性能降低,抗疲劳能力提升;融雪盐浓度增大在一定程度上降低了基质沥青的低温抗裂能力,融雪盐浓度为4wt%时,SBS改性沥青的低温抗裂能力得到提高。SBS改性沥青高低温性能总体上优于基质沥青,建议北方等寒冷地区尽量选用SBS改性沥青作为路面材料。
The effects of matrix pitch and styrene-butadiene-styrene triblock copolymer (SBS) before and after freeze-thaw cycles were investigated by atomic force microscopy (AFM), dynamic shear rheometer (DSR) and bending beam rheometer ) Modified bitumen microstructure observation and high temperature performance test. The results showed that: after freeze-thaw cycling, pitch “Bee shape ” of the number and size of the structure there are different variations in asphalt and asphaltene content increases poor dispersion condition, SBS modifier-dimensional network structure destruction ; The high temperature performance of matrix asphalt is improved, the fatigue resistance is reduced, the high temperature performance of SBS modified asphalt is reduced and the fatigue resistance is improved; the increase of the concentration of snowmelt salt reduces the low temperature crack resistance of matrix asphalt to a certain extent, Concentration of 4wt%, SBS modified asphalt cracking resistance improved at low temperature. SBS modified asphalt high temperature performance is generally better than the matrix asphalt, it is recommended that the northern region such as cold as much as possible the use of SBS modified asphalt pavement materials.