Surface functional properties of basalt fibers-modified asphalt mixtures for tunnel pavement

Basalt fibers (BFs) have emerged as a prevalent additive in pavement materials due to their capacity in enhancing mechanical properties of asphalt mixtures. With high thermal stability, superior mechanical properties, robust chemical stability, and inherent flame retardancy, BFs are anticipated further to improve the surface functional properties (i.e., skid resistance, noise reduction, and flame retardant performance) of asphalt pavements, thereby facilitating the construction of high-quality tunnel pavement systems. Hence, this study comprehensively investigated the effects of BFs on these surface functional properties in three asphalt gradations (OGFC-16, SMA-16, and AC-16) for tunnel pavement. Results showed that the incorporation of BFs increased the final skid resistance values of OGFC-16, SMA-16, and AC-16 asphalt mixtures by 9.76 %, 4.30 %, and 5.76 % (in terms of British Pendulum Number data), respectively, and significantly decreased decay rates of skid resistance by 46.67 %, 22.22 %, and 14.75 %, respectively. These improvements collectively enhanced the skid resistance and its durability of asphalt mixtures. Regarding noise reduction, incorporating BFs enhanced the performance of SMA-16 and AC-16 asphalt mixtures by 17.02 % and 12.62 %, respectively, albeit with a slight decrement in OGFC-16 (2.72 %). However, the OGFC-16 asphalt mixture with BFs outperformed SMA-16 and AC-16 gradations in reducing traffic noise. Furthermore, BFs-modified asphalt mixtures exhibited increased values of peak heat release rate (pkHRR, by 2–14.93 %), time to ignition (TTI, by 10.52–44.32 %), and fire propagation indicator (FPI, by 6.84–25.57 %), leading to the enhanced ignition resistance and reduced fire hazards. Notably, OGFC-16 gradation demonstrated the most substantial improvement. Therefore, incorporating BFs holds considerable potential for enhancing the surface properties of asphalt pavements, contributing to constructing high-quality tunnel pavements with safety, comfort, and long-lasting durability.