Why is the combination of SBS and waste rubber powder used in modified bitumen? What is the effect on bitumen properties?



The combination of SBS (styrene-butadiene-styrene block copolymer) and waste rubber powder is used in modified bitumen to improve the properties of bitumen. SBS has good elasticity and viscosity, which can increase the flexibility and crack resistance of bitumen. Waste rubber powder is a cheap filler that can increase the viscosity and stability of bitumen. Therefore, SBS and waste rubber powder combined with bitumen modification can improve the performance of bitumen.

According to the research results in the reference information, SBS/ waste rubber powder composite modified bitumen (SBS/CRMA) is more flexible at low temperatures, harder at high temperatures, less sensitive to temperature, and more resistant to rutting deformation. Specifically, the optimal composite modification scheme is 8% furfural extraction oil content (mass fraction), 25% rubber powder content (mass fraction), stirring temperature 210℃ and stirring time 2.5 hours. The SBS/CRMA prepared under this scheme has a 5℃ ductility of 327mm, a softening point of 78.0℃, and a elasticity recovery of 91.6%.

Therefore, SBS/ waste rubber powder composite modified bitumen can improve the flexibility, crack resistance and stability of bitumen, so that it has better performance at different temperatures.