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

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