随着我国公路的大规模建设，砂石资源的供需矛盾愈发突显，这已然成为制约公路行业健康发展的重大隐患。镁渣作为工业固体废料，具有潜在的水化活性和胶凝特性，具备替代路用地材的潜力，但关于其作为道路基层材料的研究应用却鲜有涉及。为此，本文提出将镁渣材料应用于道路基层，对水泥稳定镁渣基层材料组成设计、综合路用性能及路用效果等方面展开研究，以期提高工业镁废渣的固废资源化利用水平，避免由于镁废渣不当处置与堆存所带来的环境污染和安全隐患，实现经济、社会效益双增收。具体研究内容如下：

（1）以某镁业公司所生产的优化镁渣作为研究对象，研究了镁渣材料的压碎值、密度、吸水率、粒径分布、含泥量、针片状含量、自由膨胀率、化学成分及矿物组成等技术特性，结果表明镁渣材料除存在表面孔隙多、强度较低等缺陷外，其余工程特性均较为良好。

（2）结合现行规范、级配设计理论以及常用级配类型，提出采用N法设计悬浮密实型级配，采用贝雷法和SAC级配设计方法联合设计骨架密实型级配。针对镁渣材料易碎的特性，提出采用室内击实试验对设计级配进行修正，利用压密试验对混合料级配类型进行合理性验证，结果表明设计级配经优化调整后符合预设级配类型。

（3）以合成级配为基础，研究了各配合比的无侧限抗压强度、间接抗拉强度、抗压回弹模量、弹性模量、水稳定性能和抗冻性能，同时基于光学仪器分析了各配比的强度形成机理，结果表明水泥稳定镁渣基层材料具有优良的力学性能、水稳定性和抗冻性能。对比分析各性能指标，得出影响混合料性能的主要因素有水泥掺比、结构类型和养护龄期，综合分析指明所设计的骨架密实型级配性能更优。

（4）结合府谷县道路翻修改造工程，铺筑了全长200m的水泥稳定镁渣试验段，分析了水泥稳定镁渣基层材料的主要施工工艺，并采集了试验路段的现场数据，结果表明水泥稳定镁渣基层材料路用性能良好，能够满足二级及二级以下公路基层、底基层技术要求，而且可节约集料成本约25%~35%。

With the large-scale construction of highways in China, the contradiction between supply and demand of sand and gravel resources has become more and more prominent, which has become a major hidden problem restricting the healthy development of the road industry. As an industrial solid waste, magnesium slag has potential hydration activity and cementation properties, and has the potential to replace road surface materials, but little research has been done on its application as a road subgrade material. To this end, this study proposes the application of magnesium slag materials to road subgrade, the design of cement stabilised magnesium slag subgrade material composition, comprehensive road performance and road effect, in order to improve the level of solid waste resource utilisation of industrial magnesium slag, to avoid environmental pollution and safety hazards caused by improper disposal and stockpiling of magnesium slag, and to achieve economic and social benefits. The specific research content is as follows.

(1) Taking the optimized magnesium slag produced by a magnesium industry company as the research object, the crushing value, density, water absorption, particle size distribution, mud content, needle-like content, free swelling ratio, chemical composition and mineral composition of the magnesium slag material were studied. The results show that the engineering characteristics of the magnesium slag material are good except for the defects of large surface pores and low strength.

(2) Combined with the current criterion, grading design theory and common grading types, the N method is proposed to design the suspended dense grading, and the Bailey method and SAC grading design method are used to jointly design the skeleton dense grading. In view of the fragile characteristics of magnesium slag material, the indoor compaction test is proposed to correct the design gradation, and the compaction test is used to verify the rationality of the mixture gradation type. The results show that the design gradation conforms to the preset gradation type after optimization and adjustment.

(3) Based on the synthetic gradation, the unconfined compression strength, indirect tensile strength, compressive rebound modulus, elastic modulus, water stability and frost resistance of each ratio were investigated, and the strength formation mechanism of each ratio was analysed based on optical instruments. The results show that the cement-stabilised magnesia base material has excellent mechanical properties, water stability and frost resistance. By comparing various performance indexes, it is concluded that the main factors affecting the performance of the mixture are cement mixing ratio, structure type and curing age. Comprehensive analysis indicates that the designed skeleton dense gradation has better performance.

(4) Combined with the Fugu County road renovation and transformation project, paving a total length of 200 meters of cement stabilized magnesia test section, analysis of the main construction process of cement stabilized magnesia grass-roots materials, and collected the test section of field data, the results show that the cement stabilized magnesia grass-roots materials road performance is good, can meet the two levels and two levels of road grass-roots, sub-base technical requirements, and can save aggregate costs of about 25% ~ 35%.

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