Enhancement of Compatibility and Rheological Properties of Waste Low‐Density Polyethylene/Plasticizer Diisononyl Phthalate‐Modified Asphalt Using Furfural Extraction Oil and Polyphosphoric Acid

This study aimed to optimize the rheological properties and compatibility of waste low‐density polyethylene (LDPE)/plasticizer diisononyl phthalate (DINP) modified asphalt using furfural extraction oil (FEO) and polyphosphoric acid (PPA). Conventional performance and temperature scanning tests initially determined the optimum dosage ranges of FEO and PPA. The effects of FEO and PPA on the properties of waste LDPE/plasticizer DINP‐modified asphalt were investigated using dynamic shear rheology (DSR), multi‐stress creep recovery (MSCR), bending beam rheometer (BBR), segregation test, and microscopic tests. The results indicated that 1.2% FEO and 0.5% PPA significantly enhanced the high‐temperature rheological properties of waste LDPE/plasticizer DINP‐modified asphalt, with minimal impact on the low‐temperature rheological properties. The fluorescence microscopy (FM) analysis and scanning electron microscopy (SEM) test revealed that the addition of FEO and PPA resulted in a more uniform dispersion of LDPE within the asphalt. Fourier transform infrared spectroscopy (FTIR) spectra demonstrated that the incorporation of FEO and PPA introduced new characteristic peaks in the infrared spectra of the waste LDPE/plasticizer DINP‐modified asphalt, suggesting that chemical modification had occurred. FEO and PPA are added to the waste LDPE/plasticizer DINP‐modified asphalt to improve its rheological properties and compatibility, which is of significance for promoting the construction of green transportation.