Research on Morphological Characteristics and Performance Relationship of SBS-Modified Asphalt

To investigate the relationship between the morphological characteristics and performance of Styrene-Butadiene-Styrene (SBS)-modified asphalt, laser confocal microscopy experiments were conducted to observe the microstructures of modified asphalt under various preparation factors and calculate relevant characteristic parameters. Subsequently, performance tests were carried out, and the most representative characteristic parameters were selected through correlation analysis. Finally, surface function modeling was employed to analyze the particle size characteristic parameters corresponding to the optimal conditions for various performance attributes. Results indicate that SBS-modified asphalt with different morphological characteristics exhibits distinct rheological performance advantages. Among the SBS morphological features, the weighted average particle size showed the strongest correlation with the rheological performance of SBS asphalt, making it a useful parameter for analyzing its influence on rheological properties. When the weighted average particle size of SBS particles falls within the range of 2.5–3.5 μm, it corresponds to a stronger network structure, resulting in greater asphalt modulus and improved stress relaxation capacity. When the weighted average particle size of SBS particles falls within the range of 2.0–2.5 μm, it corresponds to a network structure with a balance of strength, ductility, and elasticity. Finally, when the weighted average particle size of SBS particles falls within the range of 1.7–2.0 μm, it corresponds to a network structure with excellent elasticity and ductility.