【摘要】 为加快推进建筑材料的低碳化发展，实现混凝土的全固废再生利用，以碱激发再生混凝土为研究对象，系统分析再生细骨料不同取代率对其宏观性能及微观结构的影响规律。通过工作性能、物理力学性能测试、微观表征手段及损伤过程测试，探讨再生细骨料作用机制。结果表明：再生细骨料的使用会对碱激发再生混凝土的工作性能、干表观密度、毛细吸水能力和孔隙率产生一定的不利影响，而对于超声波速与力学性能，再生细骨料存在最优取代率(50%);当再生细骨料取代率为100%时，混凝土力学性能劣化幅度不超过20%,总体性能退化较小，表明其在碱激发体系中具有较好的适用性；再生粗骨料的掺入会进一步加剧性能劣化，对结构致密性和破坏形态影响更为显著；微观分析表明，再生细骨料中的碳酸钙与碱溶液反应生成凝胶，对基体结构形成一定补偿作用；再生骨料的掺入使得碱激发再生混凝土受压破坏过程中的阶段特征变得模糊，裂缝拓展情况更为复杂；研究成果不仅能为碱激发再生混凝土的应用提供理论支持，还可为再生骨料的利用策略提供参考。更多还原

【Abstract】 To accelerate the low-carbon development of construction materials and achieve full waste recycling in concrete production, alkali-activated recycled concrete was taken as the research object, and the effects of different replacement ratios of recycled fine aggregate(RFA) on its macroscopic properties and microstructure were systematically evaluated. Through the test of workability, physical and mechanical properties, microstructural characteristics, and damage evolution, the mechanism of RFA was discussed. The results show that the use of RFA have adverse effects on the workability, dry apparent density, capillary water absorption, and porosity of alkali-activated recycled concrete to a certain extent. For ultrasonic pulse velocity and mechanical performance, there is an optimal replacement ratio of 50% for RFA. When the RFA replacement ratio is 100%, the deterioration in mechanical properties does not exceed 20%, and the overall performance degradation is small, suggesting that it has good applicability in alkali-activated systems. The incorporation of recycled coarse aggregate further aggravates performance deterioration and has a more pronounced influence on structural compactness and failure morphology. Microstructural analysis reveals that calcium carbonate in RFA reacts with the alkaline solution to form gel products, which partially compensates for matrix defects. The addition of recycled aggregates blurry the stage characteristics of compressive failure and lead to more complex crack propagation behavior. The research findings can not only provide theoretical support for the application of alkali-activated recycled concrete, but also provide reference for the utilization strategy of recycled aggregate.更多还原