Abstract: In this paper， ternary blending modifier （TBM） made of the waste polyethylene （RPE）/waste polypropylene （RPP）/polypropylene grafted maleic anhydride blend with a mass ratio of 6/4/0.7 was prepared through twin?screw extrusion together with a zonal feeding technique. The effect of different mixing time and temperature on the dynamic stability of the modified AC?20?based asphalt was studied. The morphological evolution of TBM in the modified asphalt was analyzed with a variation of mixing time. The effect of TBM content on the high?temperature and low?temperature properties of the modified asphalt was compared at TBM contents of 0， 0.2， 0.3， 0.4， and 0.5 wt%. The results indicated that under the conditions of a dry mixing time of 30 s， a wet mixing time of not less than 180 s， and a wet mixing temperature of 170 ℃， the optimum content of TBM for the modified asphalt was 0.4 wt%. This work provides a theoretical basis for the applications of RPE and RPP blends in the modified asphalt.

Key words: recycled polyethylene, recycled polypropylene, blend, modified asphalt mixture, property