老化对胶粉和SBS改性沥青流变性能的影响

Effect of Aging on Rheological Properties of Crumb Rubber and SBS Modified Asphalt

关键词:  短期老化  聚合物改性沥青  动态剪切流变试验  微观  流变性能

Key words:  short term aging  polymer modified asphalt  dynamic shear rheological test  microscopic  rheological property

摘要:

为研究短期老化作用对胶粉(CR)改性沥青和SBS改性沥青流变性能的影响，通过旋转薄膜烘箱试验(RTFOT)对CR改性沥青和SBS改性沥青进行短期老化,然后在不同温度和荷载频率下进行动态剪切流变试验(DSR)，结合扫描电子显微镜(SEM)，对CR改性沥青和SBS改性沥青的流变性能和微观结构进行了研究.结果表明：老化前橡胶粉及SBS改性剂都能与沥青达到良好共融，老化后SBS改性剂与沥青的界面结合状况却差于橡胶粉与沥青的界面结合状况；老化作用使CR改性沥青和SBS改性沥青由储存模量G′(弹性)占主导作用转向由损失模量G″(黏性)占主导作用的温度转化点向高温转移；短期老化作用在高温下对SBS改性沥青产生的影响较大；短期老化前后，CR改性沥青较SBS改性沥青具有更强的高温抵抗变形能力和抗车辙能力；随加载频率增大，2种改性沥青的高温抗车辙能力都得到增强.

Abstract:

To investigate the effect of short term aging on rheological property of crumb rubber (CR) and SBS modified asphalt, the short term aging was carried out with a rotating thin film oven (RTFOT). The dynamic shear rheological (DSR) test was performed to measure the pertinent rheological parameters while scanning electron microscopy(SEM) was employed to observe the change in microscopic asphalt internal structure due to short term aging. The results show that before aging, rubber powder and SBS modifier both can well fuse with asphalt, but after aging, interface bonding between SBS modifier and asphalt is worse. For both crumb rubber or SBS modified asphalt, aging caused the transition temperature at which G′ was replaced by G″ to play dominant function shifts towards higher temperature. At high temperatures，short term aging has a greater impact on SBS modified asphalt. Before and after aging, crumb rubber modified asphalt has larger ability to resist deformation and high rut resistance; at high temperatures, both crumb rubber and SBS modified asphalt rut resistance increases with the rise of loading frequency.