Correlation Analysis Between Rheological Properties of Plastic-Modified Asphalt Binders and Melt Flow Index

This study investigates the correlation between the melt flow index (MFI) of plastics and the rheological properties of plastic-modified asphalt binders (PMAB). To this end, virgin and waste low-density polyethylene (LDPE) plastics, with different MFI values, were used to prepare modified asphalt binders. Common asphalt binder tests including softening point, ductility, and rotational viscosity were conducted alongside the performance grading (PG) tests at high, intermediate, and low temperatures. Experimental results showed that plastics with lower MFI considerably increased the asphalt binder stiffness and rutting resistance but reduced workability and flexibility, particularly at low temperatures. Conversely, higher-MFI plastics enhanced blend uniformity and fatigue resistance at intermediate temperatures, though reduced stiffness at high temperatures. Correlation analysis between MFI and asphalt binder properties highlighted strong relationships, especially at intermediate and low temperatures, confirming MFI as a key factor in plastic modified asphalt binder performance. In addition, the results showed LDPEs with very low MFI values (less than ۰.۷۵ g/۱۰ min) do not properly disperse in the asphalt binder, leading to poor storage stability. These findings emphasize the critical role of MFI for enhancing the workability and performance of PMABS.

کلیدواژه ها:

Asphalt Binder ، Plastics ، Melt Flow Index (MFI) ، Low Density Polyethylene (LDPE)