Effect of short-term aging on rheological properties of bio-asphalt/SBS/PPA composite modified asphalt

Substituting petroleum asphalt with bio-asphalt produced by biological waste recycling can mitigate the dependence on non-renewable resource oil. This study aimed to investigate the effectiveness of bio-asphalt as a substitute for petroleum asphalt by analyzing its rheological properties. Therefore, in this study, modified asphalt was prepared using styrene-butadiene-styrene copolymer (SBS), polyphosphoric acid (PPA), and bio-asphalt (BA) as modifiers, and the short-term aging test of the modified asphalt was carried out. Then the rheological properties of the modified asphalt were analyzed through the Temperature Scanning (TS) test, the Multiple Stress Creep Recovery (MSCR) test, and the Bending Beam Rheometer (BBR) test; finally, the Fourier Transform infrared spectroscopy (FTIR) test, Fluorescence Microscopy (FM) test to study the modification mechanism and microscopic characteristics of asphalt. The results show that adding BA improved the low-temperature rheological properties of modified asphalt while reducing the high-temperature rheological properties of PPA modified asphalt. The BA, SBS, and PPA combination exhibited excellent performance in high and low-temperature conditions. The short-term aging process enhances the high-temperature rutting resistance of modified asphalt but adversely affects its low-temperature performance. Fluorescence microscopy tests have demonstrated that BA improves the compatibility of SBS and PPA in asphalt. Meanwhile, FTIR has revealed that BA and SBS are physically mixed, and BA and PPA undergo a chemical reaction. This study suggests that BA could be a viable and sustainable alternative to petroleum asphalt, with promising performance characteristics when combined with SBS and PPA modifiers.