Abstract: To reveal the freeze-thaw (F-T) damage mechanism of porous asphalt mixtures (PAMs) in cold regions, Fourier transform infrared (FTIR) spectroscopy was used to analyze the chemical composition changes of high-viscosity asphalt before and after freeze-thaw cycles. Pull-out tests were carried out to evaluate the mechanical degradation of the asphalt-aggregate interface. And combined with super depth microscopy and direct observation method, the macroscopic and microscopic morphology evolution of materials were characterized. The research results show that F-T cycling significantly intensifies water-oxygen coupling process of asphalt, causing the continuous accumulation of characteristic functional groups such as hydroxyl, carbonyl and sulfoxide groups, which leads to asphalt oxidation aging. The F-T cycling effect causes continuous attenuation of the adhesion force of asphalt-aggregate interface, and the failure mode develops from cohesive failure to detachment failure. Macro-micro analysis shows that F-T cycling induces asphalt hardening and deterioration and forms ice crystal residues on the surface of the mixture, weakening overall performance. With increasing F-T cycles, PAMs gradually experience detachment, crack development and skeleton structure damage, resulting in a decrease in mechanical properties. By analyzing the characteristics of the damage stages, the three-stage evolution mechanism of freeze-thaw damage development is revealed, and its main control indicators are determined. The research results can provide reference for the identification of freeze-thaw damage stages and the design of frost resistance durability of PAMs.

Key words: road engineering; porous asphalt mixtures; freeze-thaw damage; mechanism analysis; oxidation aging; asphalt-aggregate interface

摘要： 为揭示寒区多孔沥青混合料的冻融损伤机制，采用傅里叶红外光谱仪分析了冻融循环前后高黏沥青的化学组成变化，通过拉拔试验评价了沥青-集料界面力学性能衰退，并结合超景深显微镜与直接观测法对材料的宏微观形貌演变进行表征。研究结果表明：冻融循环显著加剧了沥青的水-氧耦合过程，使羟基、羰基和亚砜基等特征官能团持续积累，引发沥青氧化老化；冻融作用导致沥青-集料界面黏附力不断衰减，破坏模式由黏聚破坏向脱落破坏发展。宏微观分析表明：冻融循环诱导沥青硬化与劣化，并在混合料表面形成冰晶残留物，削弱整体性能；随着冻融次数增加，多孔沥青混合料逐渐出现脱落、裂隙发育与骨架结构损伤，力学性能随之下降；通过分析损伤阶段特征，揭示了冻融损伤发展三阶段演化机制并确定其主控指标。研究结果可为多孔沥青混合料冻融损伤阶段判别及抗冻耐久性设计提供参考。

关键词: 道路工程；多孔沥青混合料；冻融损伤；机制解析；氧化老化；沥青-集料界面