Performance Evaluation of Using Waste Polyethylene Terephthalate (PET) Derived Additives for Asphalt Binder Modification

Waste polyethylene terephthalate (PET) can be used as a modifier of asphalt to improve the high-temperature performance and fatigue performance of asphalt binder. However, the high melting temperature of PET, poor compatibility with virgin bitumen, and easy segregation are the main technical problems in its practical engineering application. Therefore, this study adopted triethylenetetramine to aminate PET plastics to obtain PET additives with low melting temperature, which were used to prepare PET modified asphalt (PET-VB). Subsequently, through a series of tests, including softening point, ductility, penetration, viscosity, storage stability, Fluorescence microscopy, dynamic shear rheology and multiple stress creep recovery, the effects of PET additive contents on the physical properties, compatibility, rheological properties and high-temperature properties of the virgin bitumen were evaluated. The results showed that the softening point difference of PET-VB binder is reduced to 0.3 °C ~ 0.7 °C due to the improvement of the compatibility between PET and asphalt by ammonolysis, and its storage stability is significantly improved. Moreover, PET additives contribute to improving the high-temperature properties and hardness of virgin bitumen, but reduce its ductility. PET-VB has the equivalent low-temperature fluidity with virgin bitumen, and when only 1% PET additives are added, the average recovery rate of PET-VB can increase by 11.1%, effectively improving its high-temperature deformation resistance. Overall, the proper use of waste PET plastic derivative additives as asphalt performance enhancer has important practical application value.