Influence of Compatibilizer on the Performance and Microstructure of SBS Modified Asphalt

The compatibility between styrene–butadiene–styrene (SBS) and asphalt is a crucial factor that limits the improvement of SBS-modified asphalt performance. Compatibilizers can enhance the compatibility between SBS and asphalt, thereby improving the pavement performance of asphalt. Compatibilizers primarily consist of light components such as aromatics and saturates, which can release the performance of SBS polymers to a certain extent and subsequently improve the performance of asphalt. However, excessive light components can weaken the high-temperature performance of asphalt. Therefore, this study investigates the effect of the dosage of compatibilizers on the compatibility performance of SBS-modified asphalt through conventional indicators, fluorescence microscopy, and frequency sweep tests. The results show that an increased dosage of compatibilizers leads to more uniform dispersion of SBS in asphalt and smaller particle size, as observed through fluorescence microscopy. Furthermore, the compatibility of SBS-modified asphalt improves with the increasing dosage of compatibilizers, as determined by frequency sweep tests. Finally, the conventional test indicators reveal that the high-temperature performance of SBS-modified asphalt initially increases and then decreases with an increase in the dosage of compatibilizers, while the low-temperature performance gradually improves. These findings provide insights for the preparation of high-performance SBS-modified asphalt.