The composite modified bitumen(SBS/CRMA) was prepared by adding the styrene butadiene-styrene block copolymer (SBS), which was pre-swelled by furfural extraction oil, with the addition of rubber powder.

The effects of furfural extraction oil content, rubber powder content, stirring temperature and stirring time on the properties of modified bitumenwere investigated by orthogonal test. The rheological properties of SBS/CRMA, SBS modified bitumen(SBSMA) and rubber powder modified bitumen(CRMA) were analyzed by dynamic shear rheometer, and the microstructure of SBS/CRMA was observed by fluorescence microscope.

The optimal scheme is 8% furfural extraction oil content, 25% rubber powder content, stirring temperature 210℃ and stirring time 2.5h. SBS/CRMA prepared under the optimal scheme has good performance, including the elongation of 327mm at 5℃, the softening point of 78.0℃, and the elastic recovery of 91.6%. SBS/CRMA is more flexible at low temperatures and harder at high temperatures, with reduced temperature sensitivity and increased resistance to rutting deformation.