From performance enhancement to mechanism elucidation: A comprehensive review of straw fiber-modified asphalt mixtures

With the widespread adoption of green and low-carbon principles in road engineering, biomass-modified materials, particularly straw fiber, have attracted considerable attention due to their environmental sustainability and customizable functionalities. This paper systematically reviews the preparation methods of straw fiber, its modification techniques, and the mechanisms by which it influences the road performance of asphalt mixtures. The results demonstrate that modification treatments significantly enhance the compatibility and interfacial adhesion between straw fiber and the asphalt matrix. Incorporating an optimal amount of straw fiber significantly improves the comprehensive road performance of asphalt mixtures, including high-temperature deformation resistance, low-temperature crack resistance, and moisture stability. Mechanistically, straw fiber reinforces the structure of the asphalt mixture through effects such as viscosity enhancement, reinforcement, and bridging, thereby optimizing stress transfer and enhancing the viscoelasticity of the mastic. Currently, further in-depth research is required to bridge discrepancies among existing studies, promote standardized applications, and enhance the correlation between microscopic mechanisms and long-term road performance.