双改性新工艺对大孔隙沥青混合料性能的影响

Effect of new technology of dual modification on performance of large-pore asphalt mixture

大孔隙沥青混合料一般要求其沥青为高黏改性沥青。致力于研究一种SBS湿法和橡胶粉干法双改性大孔隙沥青混合料生产工艺(简称橡胶粉干拌法)。首先,对用该新工艺制备的大孔隙沥青混合料的宏观性能进行评价并与比较试样进行对比,借由原子力显微镜(AFM)及红外光谱(FTIR)分析改性沥青微观性能。结果表明:湿拌法沥青混合料高温动稳定度、冻融劈裂强度及飞散损失率均略微优于干拌法,但差异不大。AFM分析湿拌法与干拌法混合料性能差异的内在原因是沥青“蜂状结构”及“柱状结构”数量、大小及高度存在差异。FTIR显示干拌和湿拌橡胶粉与沥青间都是物理反应变化,而且相差不大。

Macroporous asphalt mixture generally requires high viscosity modified asphalt.In this paper,a production process of SBS wet process and dry process of rubber powder double modified macroporous asphalt mixture(dry mixing process of rubber powder for short)was studied.Firstly,the macro properties of the macroporous asphalt mixture prepared by the new process were evaluated and compared with the comparison samples.Secondly,Atomic Force Microscopy(AFM)and infrared spectroscopy(FTIR)were used to analyze the microscopic properties of modified asphalt.The results show that the dynamic stability at high temperature,freeze-thaw splitting strength and flight loss rate of wet mixed asphalt mixture are slightly better than those of dry mixed asphalt mixture,but the differences are not significant.AFM analysis shows that the intrinsic reason for the performance difference between wet and dry mixtures is the difference in the number,size and height of“bee structure”and“column structure”of asphalt.FTIR showed that physical reaction changes between dry and wet rubber powder and asphalt were not significant.