Comparative Study on Asphalt Mixtures for the Surface Course of Semi-rigid Base Pavements of High-grade Highways

This study focuses on the surface course of semi-rigid base pavements of high-grade highways. Three types of asphalt mixtures are designed and compared: traditional lignin-fiber SMA-13, AC-13, and basalt-fiber SMA-13. Starting from aspects such as material selection, mix proportion design, and performance testing, the applicability of different types of asphalt mixtures is comprehensively evaluated. Through experiments, the physical and mechanical properties of these mixtures are analyzed, their stability under different environmental conditions is assessed, and their cost-effectiveness is compared. The experimental results show that basalt-fiber SMA-13 performs excellently in terms of high-temperature stability, low-temperature crack resistance, and water-damage resistance, and its optimal asphalt content is significantly lower than that of lignin-fiber SMA-13. The economic benefit analysis indicates that AC-type asphalt mixtures have an obvious price advantage. However, in the long run, due to its excellent performance and lower material cost, basalt-fiber SMA-13 may be more economical. This study provides a scientific basis for the design, construction, and maintenance of semi-rigid base pavements. Meanwhile, while ensuring pavement performance, efforts are made to reduce the overall construction cost, achieving a win-win situation of economic and social benefits.