Enhancing crack resistance in basalt fiber asphalt mixtures: a full-field time-domain investigation of stress distribution and pore structure optimisation
Lin Kong, Jiarui Xu, Haibo Yang, Pengfei Wu, Xueyou Li, Delong Ma, Zilin Wang, Dongya Ren, Changfa Ai
Abstract
This study explores the crack propagation process and the mechanism underlying enhanced crack resistance at phase interfaces in basalt fiber asphalt concrete (BFAC). Semicircular bending tests were conducted on asphalt concrete (AC) and BFAC using a Universal Testing Machine (UTM). Real-time strain and displacement variations were captured across different temperatures using the Extended Digital Image Correlation (XTDIC) system, providing insights into the influence of basalt fibers on stress distribution during loading. Additionally, X-ray Computed Tomography (CT) enabled three-dimensional visualization and quantification of microstructural changes, including pore number, volume, and equivalent diameter, before and after fiber incorporation. Results indicate that basalt fibers establish a complex spatial stress network, optimizing pore distribution and delaying micro-crack propagation. They effectively disperse stress concentrations, mitigate small defects, and refine pore structures, thereby enhancing internal density and deformation resistance. This study systematically elucidates the reinforcement mechanism of BFAC by integrating strain evolution analysis with microstructural characterization, offering a comprehensive understanding of its crack resistance behavior.