Study on the high-temperature performance and self-healing capability of asphalt modified with pyrolysis oil from waste tires and polyphosphoric acid

To develop a novel self-healing asphalt binder and address the challenge of poor performance of waste tire pyrolysis oil-modified asphalt at high temperatures, this study employed polyphosphoric acid and waste tire pyrolysis oil for composite modification of asphalt. Subsequently, comprehensive evaluations of the modified asphalt were conducted using experimental techniques such as temperature sweep, time sweep, differential scanning calorimetry, Fourier-transform infrared spectroscopy, and fluorescence microscopy. The entropy weight method was utilized to determine the optimal dosage of modifiers in the asphalt binder and evaluate the comprehensive performance of the modified asphalt. Experimental results indicate that the introduction of polyphosphoric acid not only effectively maintains the self-healing properties of the modified asphalt but also significantly improves the negative impact of waste tire pyrolysis oil on the high-temperature performance of the asphalt binder. Analysis using the entropy weight method revealed that the optimal dosages of 2% polyphosphoric acid and 4% waste tire pyrolysis oil served as modifiers, resulting in the superior overall performance of the modified asphalt at these concentrations. In conclusion, the development of polyphosphoric acid/waste tire pyrolysis oil composite modifiers offer a novel avenue for the sustainable enhancement of asphalt modification.