Abstract: The frost resistance of road concrete is one of the most important factors in the durability of cement pavement.In order to understand the essence of road concrete frost resistance changes in the law，the freezing regularity of road concrete under different water-cement ratios and gas contents have been explored using the quick freeze method， and the stomatal structure and pore structure of road concrete have been analyzed using a Scanning Electron Microscope- Image Pro-plus (SEM-IPP) that were invented by the research group and Mercury Injection Porosimetry (MIP)，with the results of both macro and micro tests having been analyzed.The results show：the average pore diameter and stomatal spacing decreased by 30% and 22% respectively when the water-cement ratio decreased by 0.04，meanwhile，the frost resistance of road concrete increased by 15%; the average pore diameter and stomatal spacing decreased by 44% and 51% respectively, the frost resistance of road concrete increased by 35% when increased air entraining content 1/10 000.The increase in percentage of the <50 nm holes and the decrease of the average pore diameter and stomatal spacing resulting from the decreasing water-cement ratio or increasing air entraining content improved the internal structure of the pores and pore structures and reduced fractures，large holes，and hole connectivity，thus making the internal microstructure dense，which is beneficial to the improvement of frost resistance of road concrete.

Key words: highway engineering, road concrete, frost resistance performance, micro structure, micro-mechanism

摘要： 道路混凝土抗冻性是影响水泥路面耐久性的重要因素之一，为了从本质上认识道路混凝土抗冻性变化规律，通过快冻法探寻了不同水灰比 和含气量条件下道路混凝土抗冻性的变化规律，借助自主研发的SEM-IPP法及压汞试验计算分析道路混凝土的气孔结构和孔结构，基于宏观与微观 试验结果分析，揭示微观结构对抗冻性的影响机理。结果表明：水灰比从0.44降至0.40，平均气孔孔径和气孔间距分别下降30%和22%，道路混凝 土抗冻性提高15%；在水灰比为0.44条件下，掺入引气剂1/10 000，平均气孔孔径和气孔间距分别下降44%和51%，道路混凝土抗冻性提高35%；降 低水灰比和增加含气量增大了混凝土内部＜50 nm孔所占百分比并降低平均孔径和气孔间距，从而改善了混凝土内部气孔结构和孔结构，同时使得 混凝土微观结构中裂缝和大孔数量减少，整体趋于连续密实结构，降低了孔间连通性，有利于道路混凝土抗冻性的提高。

关键词: 道路工程, 道路混凝土, 抗冻性, 微观结构, 微观机理