Performance assessment of self-healing polyurethane elastomer as an additive in modified asphalt†

Since the development of polymer-modified asphalt, its functionality and preparation process have been continuously optimized, thus improving driving comfort and extending the service life of asphalt pavements. However, traditional polymer-modified asphalt is faced with certain limitations in terms of production and storage. To address these issues and enhance the storage stability of modified asphalt materials, a novel polyurethane (PU) elastomer with high elasticity and self-healing properties, named S-PU, was developed using dynamic covalent bond reversible technology. S-PU was applied as a modifier for asphalt modification. Through conventional performance and fluorescence microscopy (FM) tests, the optimal dosage of S-PU for asphalt modification was determined. The best asphalt modification effect was achieved when the S-PU content was 10%. Furthermore, atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FT-IR) were employed to analyze the micromorphology and modification mechanism of S-PU-modified asphalt. The results reveal an increase in the size of the “bee-like” structures after asphalt modification, along with chemical crosslinking between S-PU and asphalt molecules. This study introduces a novel approach for preparing self-healing asphalt through the utilization of dynamic covalent chemistry, offering new perspectives in the field.