Improving the Resistance of Asphalt to Thermal Oxygen Aging by Adding Waste Rubber Powder

The accumulation of waste tires has wasted substantial resources and has caused environmental pollution, which are not easy to reverse. Rubber powder prepared from waste tires could improve asphalt performance and prolong the service life of pavement. Therefore, the influence of rubber powder on the rheological and adhesion properties of different asphalts before and after aging were studied. At same time, the relation between rheological properties and functional groups of rubber modified asphalt after aging was investigated. The results show that the complex modulus of base asphalt and styrene-butadiene-styrene (SBS) modified asphalt were increased by 45% and 58%, respectively, after adding rubber powder. Moreover, the resistance to the deformation and elastic recovery ability of asphalt can be improved by adding rubber powder. After aging, compared with the original asphalt carbonyl functional group index, the increased amount is reduced by 90% and 49%, respectively, and the aging resistance of asphalt was improved. Furthermore, the correlation coefficient between the rheological parameters and the functional group index was higher than 0.91, indicating that the improvement in the rheological properties of asphalt was mainly due to the changes in the carbonyl and sulfoxide functional groups. Compared with the original asphalt, the range of rubber powder modified asphalt and composite modified asphalt under aging increased by 68% and 2%, respectively. Rubber powder has a promoting effect on improvements in the adhesion properties of asphalt when it was aged.