Study On Performance Of Warm Mix Recycled SBS Asphalt And Asphalt Mixture

In view of the large stock of waste asphalt mixture on the existing road surface,which causes a waste of resources,Traditional hot recycled asphalt mixture due to high construction temperature and the problem of secondary asphalt aging cannot be used continuously.At the same time,the construction process not only pollutes the environment,high energy consumption,but also limits the proportion of RAP.HMA’s low-temperature performance and the water stability are both terrible.This paper combined with warm mixing technology started a systematic and in-depth research on warm-mix recycled SBS modified asphalt and asphalt mixture.First of all,the paper started a systematic evaluation of the recycled asphalt mixture,including recycled asphalt mixture grading composition and asphalt aging degree,etc.Started a artificial simulation of the natural aging of SBS modified asphalt.And then compared with the different rejuvenation methods,including the components modification,rejuvenators modification and composition modification.Selecting a reasonable rejuvenation method.The results show that it had a obvious variation in the gradation of recycled asphalt mixture and asphalt aging is serious.The SBS modified asphalt aged by RTFOT(300min,163℃)are closer to natural aging asphalt.Comprehensive rejuvenation effect and economic considerations,Selecting compositions modification as a reasonable rejuvenation method.Secondly,Mixing Sasobit(S)and Evotherm(E)into the composite recycled SBS modified asphalt separately.Study its influence on the temperature sensitivity,adhesion and high temperature performance of warm-mix recycled SBS modified asphalt and analyze the microstructure of warm-mix recycled SBS modified asphalt.The results show that Sasobit has perfect compatibility in the recycled SBS modified asphalt,its viscosity is greatly reduced,and G* is obviously increased,but its force ductility value is reduced,and its adhesion to aggregate is insufficient,and a series of chemical reactions can occur with recycled asphalt.Evotherm mixed in recycled SBS modified asphalt can greatly promote the low-temperature performance,what’s more,the viscosity will be declined,the high temperature indexes of recycled asphalt will be decreased.Evotherm only plays a physical mixing role with asphalt.Finally,this paper started a grading mix design about the warm-mix recycled SBS modified asphalt mixture,and researched road performance verification,comprehensive benefit analysis.The results show that the quantity of asphalt is positively correlated with the quantity of RAP.Sasobit and Evotherm can reduce the mixing and molding temperature of the SBS asphalt mixture by 10～17℃ and 15～23℃ respectively on the basis of RAP content of 0%,10%,30% and 50%.Warm mix recycled SBS modified asphalt has good economic and environmental benefits.