Asphalt/polyethylene blends: Rheological properties, microstructure and viscosity modeling

• Different polyethylene and grafted polyethylene-based polymers were used to modify asphalt.
• Grafted polymers allow for an improvement in the miscibility between polymer and asphalt.
• Elastic properties of the binder at high temperatures were enhanced. These results allow knowing the reduction of rutting.
• Grafted polymers showed strong interactions, which are evidenced by the apparition of a plateau region at low frequencies.
• Frequency sweeps to estimate the ZSV in asphalts and blends were analyzed in this work.

In this work, an analysis on chemically-grafted polyethylenes as asphalt modifiers was carried out. Results show that the softening point of asphalt increased, while the penetration degree decreased in blends prepared with grafted polyethylene. The phase distributions of micrographs from fluorescence microscopy show that non-grafted polyethylene polymers were not readily miscible with asphalt. Rheological tests indicate that most of asphalt blends exhibit improved performance at higher temperature with grafted polyethylene such as enhancing rutting resistance, flow activation energy and superior time–temperature-dependent response as compared to the reference polyethylene blends. Zero shear viscosity (ZSV) was calculated using the different models available in literature to determine its suitability in predicting the rutting behavior of asphalt binders.