Compound modification of asphalt with styrene-butadiene-styrene and waste polyethylene terephthalate functionalized additives

The modification of asphalt binder using recycled plastics such as polyethylene terephthalate (PET) may improve its rheological characteristics while providing secondary environmental benefits. In this study, the chemical recycling of PET was conducted to synthesize additives and used in conjunction with styrene-butadiene-styrene (SBS) to modify asphalt binder. The properties of the modified asphalt binder (PS-MB) were characterized through both conventional binder tests, including penetration, softening point, viscosity, and storage stability tests, and Superpave binder tests, such as multiple stress creep recovery (MSCR), rutting factor (G∗/Sinδ), fatigue factor (G∗Sinδ), and low temperature creep stiffness tests. These properties were then compared with those of the unmodified asphalt binder and asphalt binder modified with SBS (S-MB). To study the effects of PET additives on the physical and chemical structures of S-MB, additional analyses were done using scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy. The outcomes of the laboratory investigation indicated that using waste PET derived additives as modifiers for SBS modified asphalt binder not only provides a functioning way to recycle waste PET, but also enhances the rheological properties of SBS modified asphalt binder as a paving material.