Abstract: To improve the mechanical properties and shrinkage properties of recycled base, different dosages of recycled aggregate and alkali-activated lithium slag were used to prepare alkali-activated lithium slag recycled cement stabilized macadam mixtures, and their mechanical properties, microscopic properties and shrinkage properties were investigated. The gray correlation method was further employed to investigate the correlation between the proportions of recycled aggregate and alkali-activated lithium slag and various performance parameters of the mixture. The results indicate that as the proportion of recycled aggregate increases, the mechanical properties of the recycled cement stabilized macadam mixture firstly increase and then decrease, while the drying shrinkage coefficient and temperature shrinkage coefficient gradually increase. The optimal proportions of alkali-activated lithium slag and recycled aggregate are 15% and 40%, respectively. Compared with the mixture of only 40% recycled aggregate, the alkali-activated lithium slag recycled cement stabilized macadam mixture exhibits an increase in 7-day compressive strength, splitting strength, and flexural strength by 12.9%, 8.8%, and 12.7%, respectively. Additionally, its 7-day and 28-day drying shrinkage coefficients decrease by 15.8% and 28.1%, respectively, while the average temperature shrinkage coefficient is reduced by 5.4%. The analysis of gray correlation method indicates that the correlation between the dosage of alkali-activated lithium slag and the mechanical properties and average temperature shrinkage coefficient of the mixture is higher, and the effect of recycled aggregate dosage on the drying shrinkage coefficient of the mixture is more significant. Microscopic experiments demonstrate that alkali-activated lithium slag participates in the hydration reaction, generating hydrated silicate and ettringite, which optimizes the interfacial transition zone of the mixture and makes its microstructure denser.

Key words: highway engineering; cement stabilized macadam mixtures; recycled aggregates; alkali-activated lithium slag; microscopic properties; gray correlation analysis

摘要： 为了改善再生基层的力学性能和收缩性能，以不同掺量的再生骨料、碱激发锂渣制备碱激发锂渣再生水泥稳定碎石混合料，并对其力学性能、微观特性和收缩性能进行了研究。采用灰色关联法进一步分析了再生骨料和碱激发锂渣掺量与混合料各项性能的关联性。结果表明：随再生骨料掺量的增加，再生水泥稳定碎石混合料的力学性能先升高后降低，干缩系数和温缩系数逐渐升高；碱激发锂渣和再生骨料的最佳掺量为别为15%和40%，较纯40%再生骨料混合料，碱激发锂渣再生水泥稳定碎石混合料的7 d抗压强度、7 d劈裂强度、7 d弯拉强度分别提升了12.9%、8.8%、12.7%，7 d、28 d干缩系数分别降低了15.8%、28.1%，平均温缩系数下降了5.4%。灰色关联法分析表明，碱激发锂渣掺量与混合料的力学性能及平均温缩系数的关联度更高，再生骨料掺量对混合料干缩系数的影响更显著。微观试验表明，碱激发锂渣参与水化反应，生成水化硅酸盐和钙矾石，优化了混合料的界面过渡区，使混合料的微观结构更加紧实。

关键词: 道路工程；水泥稳定碎石混合料；再生骨料；碱激发锂渣；微观特性；灰色关联分析