Abstract
This study investigates the microstructural evolution and rheological behavior of bitumen modified with partially devulcanized rubber (DVR) in combination with virgin polyethylene (vPE) and recycled polyethylene (rPE). The structural characteristics of the modifiers were evaluated through sol–gel analysis and crosslink density determination, while fluorescence microscopy was employed to assess the dispersion of polymer phases within the bitumen matrix. Rheological properties were analyzed using dynamic viscosity and shear stress-shear rate measurements. The results demonstrate that rPE-modified systems exhibit significantly improved compatibility with bitumen, leading to a finer and more homogeneous microstructure compared to vPE-based compositions. This enhanced dispersion contributes to a 20-35% increase in viscosity and higher shear resistance, indicating the formation of a more developed internal structure. The incorporation of Aerosil (А) further increases viscosity by approximately 1.5-2 times due to the formation of a threedimensional network that restricts phase mobility and enhances interfacial interactions. Overall, the DVR-rPE-A system exhibits superior rheological stability and structural homogeneity. The findings provide new insights into the mechanisms governing polymer-rubber-bitumen interactions and demonstrate the potential of recycled polyethylene for tailoring the rheological performance of modified binders.