Waste-chopped basalt fiber as a high-performance asphalt mixture modifier: Multi-temperature domains performance characterization based on fiber characteristic parameters

This study systematically investigates the synergistic effects and mechanisms of waste-chopped basalt fiber (WCBF) with varying characteristic parameters (lengths: 3, 6, 12 mm; diameters: 7, 16, 25 μm) on asphalt mixture (AM) performance across high, medium and low-temperature domains. The primary objective is to establish a quantitative relationship between the characteristic properties (length and diameter) of WCBF and the multi-temperature performance of basalt fiber reinforced asphalt mixture (BFAM), thereby optimizing the fiber characteristic parameters to achieve sustainable pavement applications. Uniaxial dynamic creep tests, direct tensile cyclic fatigue tests, and thermal stress-restrained sample tests were employed to evaluate high-temperature deformation resistance, intermediate-temperature fatigue behavior, and low-temperature crack resistance. Dynamic modulus analysis and equal cross-section theory were further applied to elucidate the synergistic mechanisms. The results indicate that the characteristic parameters of WCBF consistently influence the asphalt mixture across diverse temperature domains. When the fiber diameter remains constant, the performance of BFAM exhibits an initial increase followed by a subsequent decrease with increasing fiber length. Conversely, when the fiber length is fixed, a decrease in performance is observed with an increase in fiber diameter. The optimal performance of the asphalt mixture when blended with BF-6-7 was observed across all temperature domains. The characteristic parameters of the fibers directly affect the monofilament dispersion and interfacial adhesion regulated by the specific surface area, the formation of the stress transfer spatial network, and the proportional regulation of the viscoelastic components, which are the main factors affecting the performance of AM. Notably, smaller diameters maximized the cross-sectional moment of inertia, while intermediate lengths balanced fiber-asphalt interactions and defect minimization. This paper reuses waste-chopped basalt fibers by changing their characteristic parameters, and the modification effect and mechanism of fiber characteristic parameters on the performance of asphalt mixtures were studied, providing ideas and technical references for the efficient utilization of WCBF.