聚合物改性沥青结合料老化前后低温流变性能研究

Polymer modified asphalts before and after aging on the low temperature rheological property of asphalt

采用5℃延度实验和弯曲梁流变实验(BBR)结合扫描电子显微镜(SEM)测试,以宏观和微观分析相结合的手段,研究了复合胶粉(CCR)改性沥青、橡胶粉(CR)改性沥青和SBS改性沥青老化前后的低温流变性能。结果表明,老化前3种聚合物改性剂与沥青都能达到很好的共融,CCR改性沥青由于两种改性剂的共同作用产生了比单一改性剂更加无规则的空间网状结构,老化后3种改性剂与沥青间界面特性劣化,CCR改性沥青的改性剂与沥青的界面结合情况好于CR和SBS改性沥青;在正温区内,CCR改性沥青老化前后低温抗裂性能最好,SBS改性沥青次之,CR改性沥青最差,在负温区内,CR改性沥青老化前后低温抗裂性能反而优于SBS改性沥青;不同程度老化作用对CR改性沥青劲度模量S和温度敏感性的影响程度都大于CCR改性沥青和SBS改性沥青。

Using ductility test(5℃),bending beam rheometer(BBR)and scanning electron microscopy(SEM)to study the low temperature rheological properties of composite crumb rubber(CCR),crumb rubber(CR)and SBS modified asphalt from macro and micro dimensions.The results show that:before aging,rubber powder and SBS modifier has good fusion with asphalt,the space grid structure of CCR was more irregular compared with CR and SBS,and after aging,the interface of modifier and asphalt was worse for both asphalts,interface bonding of CCR modified asphalt was batter than the others;when the temperature was above zero,CCR modified asphalt has the best low-temperature crack resistance among them,and then was SBS modified asphalt,CR modified asphalt was the worst wherever aging or not;but when the temperature was below zero,the low-temperature crack resistance of CR modified asphalt was batter than SBS modified asphalt instead;CR modified asphalt has larger influence on stiffness modulus(S)and higher temperature sensitivity than CCR modified asphalt and SBS modified asphalt on different aging effects.