Low-temperature performance investigation on fiber-reinforced high-viscosity asphalt mastic

This study investigates the low-temperature rheological properties and microscopic mechanisms of high-viscosity modified asphalt mastic modified with fibers. The effects of two asphalt types (high-viscosity modified asphalt and SBS-modified asphalt), two filler types (limestone mineral powder and dust), two fiber types (polyester and basalt), and four fiber contents (0%, 0.5%, 1%, and 1.5%) on the low-temperature rheological behavior of high-viscosity modified asphalt mastics under long-term aging were evaluated using bent beam rheological test (BBR), infrared spectrum test (FT-IR), and differential scanning calorimetry test (DSC). Results indicate that increasing fiber and filler content reduces the low-temperature cracking resistance of high-viscosity modified asphalt mastic. The incorporation of high-viscosity additive enhances the viscoelasticity of the mastic. Compared to mineral filler, the asphalt binder plays a dominant role in determining the low-temperature performance of the mastic. The two fiber types exhibit considerable differences in their effects on low-temperature rheological properties. Overall, both fibers and high-viscosity modified asphalt tend to harden under long-term aging, reducing mastic flexibility. At the same fiber content, basalt fiber-reinforced mastic shows higher low-temperature continuous grading temperature, pure viscosity parameter, and relaxation time compared to polyester fiber-reinforced mastic, indicating a more pronounced adverse effect of basalt fiber on low-temperature rheological performance.