基于综合指数法的胶粉/SBS复合改性沥青性能评价

Performance evaluation of crumb rubber/SBS composite modified asphalt based on comprehensive index method

为了实现废旧轮胎的资源化利用、将废旧轮胎回收粉碎后用于公路工程的建设,制备了不同胶粉活化度的高掺量双螺杆挤出法(twin-screw extrusion process,TSEP)活化胶粉/SBS复合改性沥青试样,对其常规性能进行测试,采用动态剪切流变仪(dynamic shear rheometer,DSR)对复合改性沥青进行高温温度扫描、多应力蠕变恢复(multi-stress creep recovery,MSCR)试验及线性振幅扫描(linear amplitude scanning,LAS)试验,探究胶粉活化度和掺量对复合改性沥青高温流变特性、高温抗车辙性能及中温抗疲劳性能的影响,同时采用综合指数法综合评价高掺量TSEP活化胶粉复配SBS改性沥青性能。结果表明:高掺量TSEP活化胶粉复配SBS改性沥青的常规指标均得到改善,尤其是ERP-B/SBSCMA黏度最低,相较于其他5种改性沥青具有更好的施工和易性;随胶粉活化度的提高,其复合改性沥青的高温抗车辙性能有所下降。33%胶粉掺量的ERP-B/SBSCMA的高温性能优于20%胶粉掺量的ERP-B/SBSCMA-20;随着温度的升高,车辙因子提高了9%~40%;抗疲劳性能也有所提高。ERP-B的活化程度适中,其复合SBS改性沥青具有良好的常规性能、高温抗变形性能及中温抗疲劳性能。

Waste tires can be employed in highway engineering construction after recycling and crushing to realize resource utiliza⁃tion.In this study,high-volume twin-screw extrusion process(TSEP)activated rubber powder/SBS composite modified asphalt samples with different rubber powder activation degrees were prepared,and their conventional properties were tested.At the same time,dynamic shear rheometer(DSR)was used to perform high-temperature temperature scanning,multi-stress creep recovery(MSCR)test and linear amplitude scanning(LAS)test on the composite modified asphalt.Based on these sampling and testing,the effects of rubber powder activation degree and content on high-temperature rheological properties,high-temperature rutting resis⁃tance and medium-temperature fatigue resistance of composite modified asphalt were explored systematically.The performance of SBS modified asphalt with high content of TSEP activated rubber powder was evaluated by comprehensive index method.The results show that the conventional indexes of SBS-modified asphalt compounded with high amount of TSEP-activated binder are improved,especially for ERP-B/SBSCMA which has the lowest viscosity and better construction and ease of use than the other five types of modified asphalt.With the increase of the activation degree of the binder,the high temperature rutting resistance of its com⁃posite modified asphalt decreases.High temperature performance of ERP-B/SBSCMA with 33%binder dosage is better than 20%binder dosage of ERP-B/SBSCMA-20.With the temperature increase,the rutting factor increases by 9%-40%.Fatigue resistance has also been improved.The activation degree of ERP-B is moderate,and its composite SBS-modified asphalt has good conven⁃tional performance,high-temperature deformation resistance,and medium-temperature fatigue resistance.