水泥稳定再生碎石物理力学性能研究进展

Research Progress on Physical and Mechanical Properties of Cement Stabilized Macadam Incorporating Recycled Aggregate

再生集料的使用对交通基础设施建设的可持续发展具有重要意义,将其用于集料占比大而强度要求低的水泥稳定碎石基层具有较大的推广价值,但目前相关研究及应用较少,缺乏系统总结。本文对水泥稳定再生碎石物理力学性能研究进行综述,统计了再生集料基本性能指标,总结了再生集料、水泥、龄期和外掺物等因素对水泥稳定再生碎石物理力学性能的影响,得到以下结论:再生集料性能较低,应进行表面处理并合理掺配,当掺量小于40%时,水泥稳定再生碎石各项性能降幅均较小,掺量较大时性能降低显著;再生集料替代粒径越大,干燥收缩性能越高,但强度、刚度和抗冲刷等性能降低;水泥掺量的增加提高了水泥稳定再生碎石的强度、刚度、抗冲刷和疲劳等性能,但其收缩性能降低,因此在满足基层强度和刚度的基础上,应适当减少水泥掺量以有效降低收缩;水泥稳定再生碎石的强度和收缩等均在28 d龄期达到稳定,因此其应进行适当龄期的养护,以满足后续面层施工要求;添加适当的外掺物虽然降低了水泥稳定再生碎石的强度和刚度,但提高了其收缩和疲劳性能,因此可缓解基层开裂。然而,不同粒径的再生集料对水泥稳定再生碎石物理力学性能的影响机理不明确,可将其作为今后研究的切入点,为其在路面工程设计和施工中的应用提供理论和技术支撑;此外,不同来源的再生集料对水泥稳定再生碎石性能的影响不同,今后研究应以吸水率和压碎值等作为修正系数控制指标,对其掺量与水泥稳定再生碎石性能模型进行修正。

The application of recycled aggregate material in transportation infrastructure construction is essential for sustainable development.There is great potential for the use of large proportions of recycled aggregate in cement stabilized macadam bases with low strength requirements.However,there is a lack of systematic research and applications in this area.Research on the physical and mechanical properties of cement stabilized macadam incorporating recycled aggregate has been reviewed in this paper.The basic performance indicators of recycled aggregates are summarized,and the effects of recycled aggregate,cement,age and additives on the physical and mechanical performance of cement stabilized macadam are analyzed.The following conclusions are drawn:the performance of recycled aggregates is relatively limited,and thus surface treatment and appropriate mixing should be conducted.When the recycled aggregate content in cement stabilized macadam is less than 40%,the performance of the macadam decreases only slightly,while a higher aggregate content causes a significant decrease in performance.The larger the particle size of the recycled aggregate is,the greater the dry shrinkage performance,but with a decrease in strength,stiffness and anti-scouring performance.Increasing the cement content can improve the strength,stiffness,anti-scouring and fatigue performance of cement stabilized ma-cadam incorporating recycled aggregate,but shrinkage performance decreases.Therefore,the cement content should be reduced appropriately to effectively reduce shrinkage while ensuring the strength and stiffness of the subgrade.The strength and shrinkage of cement stabilized maca-dam incorporating recycled aggregate stabilize at 28 days;appropriate maintenance should be performed to meet requirements of subsequent surface construction.Adding appropriate additives reduces the strength and stiffness but improves the shrinkage and fatigue properties;this can be used to reduce base cracking.However,effects of different particle sizes on physical and mechanical properties of cement stabilized macadam incorporating recycled aggregate are still unclear.The results of this study can be used as the basis for future research to provide theoretical support for the application of recycled aggregates with different particle sizes in pavement engineering design and construction.In addition,recycled aggregates from different sources have varying impacts on the performance of cement stabilized macadam.Therefore,in future research,water absorption and crushing value should be used as the control indexes of the correction coefficient,and models of content and performance should be modified accordingly.