盐冻循环条件下改性沥青的微观结构及重复蠕变特性

发布时间：2018-08-30 09:03

【摘要】：为考察在融雪盐环境下路面材料的性能变化情况,对内蒙古寒冷地区常用的SBS(苯乙烯-丁二烯-苯乙烯嵌段共聚物)改性沥青和胶粉改性沥青利用动态剪切流变仪(DSR)进行重复蠕变试验,利用原子力显微镜(AFM)进行微观结构观测,比较分析盐冻循环前后两种沥青的微细观结构以及流变学性能的变化,为寒冷地区道路路面材料的选择和使用提供参考依据。AFM测试发现,SBS改性沥青出现"蜂形"结构,冻融循环后,"蜂形"结构出现不同变化;胶粉改性沥青未出现"蜂形"结构,冻融循环后胶粉改性沥青表面形貌相差不大;重复蠕变试验结果显示:冻融循环前后SBS改性沥青和胶粉改性沥青永久变形与卸载瞬时应变的比值(εP/εL)在加载初期均随着加载次数的增加而增加,一定次数后达到稳定状态;冻融循环后SBS改性沥青的εP/εL降低,胶粉改性沥青的εP/εL基本不变;利用Burgers模型拟合得到蠕变劲度的黏性成分G_v,冻融循环后SBS改性沥青G_v值小于原样SBS改性沥青,胶粉改性沥青G_v值大于原样胶粉改性沥青,且两种沥青水冻循环与盐冻循环G_v值差别不大。胶粉改性沥青具有更好的高温使用性能。
[Abstract]:In order to investigate the performance changes of pavement materials under the environment of snowmelt salt, The repeated creep tests of SBS (Styrene-Butadiene-Styrene Block Copolymer) and Rubber modified Asphalt in Cold region of Inner Mongolia were carried out by means of dynamic shear rheometer (DSR), and the microstructure was observed by atomic force microscope (AFM). The changes of microstructures and rheological properties of two kinds of bitumen before and after salt freezing cycle were compared and analyzed, which provided a reference basis for the selection and application of road pavement materials in cold regions. AFM test found that SBS modified asphalt had a "bee shape" structure. After freeze-thaw cycle, the "bee shape" structure changed differently, the rubber powder modified asphalt did not appear "bee shape" structure, and the surface morphology of the asphalt modified by rubber powder did not differ significantly after freeze-thaw cycle. The results of repeated creep test showed that the ratio of permanent deformation to unloading instantaneous strain (蔚 P / 蔚 L) of SBS modified asphalt and rubber powder modified asphalt before and after freeze-thaw cycle increased with the increase of loading times at the beginning of loading, and reached a stable state after a certain number of times. The 蔚 P / 蔚 L of SBS modified asphalt was decreased after freeze-thaw cycle, and 蔚 P / 蔚 L of rubber powder modified asphalt was almost unchanged, the viscosity component of creep stiffness was obtained by Burgers model fitting, and the GV value of SBS modified asphalt after freeze-thaw cycle was lower than that of original SBS modified asphalt. The GV value of rubber powder modified asphalt is higher than that of raw rubber powder modified asphalt, and the GV value of the two kinds of asphalt is not different from that of salt freezing cycle. Rubber powder modified asphalt has better performance at high temperature.
【作者单位】：内蒙古工业大学土木工程学院;内蒙古电力科学研究院;
【基金】：国家自然科学基金(11162010;51568054)
【分类号】：U414

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