地聚物稳定碎石基层路用性能研究

Research on Road Performance of Geopolymer-Stabilized Crushed Stone Base Course

摘要: 本文通过与水泥稳定碎石做比较，研究地聚物稳定碎石在道路基层上的性能表现，两组试验胶凝剂含量均为5%。从原材料出发，发现地聚物有着绿色环保的优点。通过击实试验，得出地聚物稳定碎石比水泥稳定碎石的最大干密度更高，说明前者的密实性更好。通过单轴抗压试验、劈裂试验、冻融循环试验以及干缩试验来综合考量地聚物稳定碎石的路面性能。结果表明：地聚物稳定碎石的抗压强度和劈裂强度均略低于同掺量下的水泥稳定碎石。根据冻融循环试验结果，进行破坏机理分析，得到地聚物稳定碎石的破坏是由于自身刚性不足而引起的脆性断裂。本文末尾对地聚物稳定碎石和水泥稳定碎石28 d抗压强度的损坏试件进行微观试验，利用SEM-EDS技术分析了两种材料的微观形貌与元素组成，利用XRD技术分析了地聚物的元素组成和晶格结构，并总结出地聚物材料的强度形成机理。最终得出：地聚物稳定碎石满足规范中对道路基层材料的要求，有望代替水泥成为新型绿色半刚性基层材料。

Abstract: This paper studies the performance of geopolymer-stabilized crushed stone in road base by comparing it with cement-stabilized crushed stone, with the content of both binders being 5%. Starting from raw materials, it is found that geopolymer has the advantage of being environmentally friendly. Through compaction tests, it is concluded that the maximum dry density of geopolymer-stabilized crushed stone is higher than that of cement-stabilized crushed stone, indicating that the former has better compactness. The pavement performance of geopolymer-stabilized crushed stone is comprehensively evaluated through uniaxial compression tests, splitting tests, freeze-thaw cycle tests and dry shrinkage tests. The results show that the compressive strength and splitting strength of geopolymer-stabilized crushed stone are slightly lower than those of cement-stabilized crushed stone with the same dosage. Based on the results of the freeze-thaw cycle test, the failure mechanism is analyzed, and it is found that the failure of geopolymer-stabilized crushed stone is caused by brittle fracture due to insufficient rigidity. At the end of the paper, microscopic tests are conducted on the damaged specimens of geopolymer-stabilized crushed stone and cement-stabilized crushed stone with 28-day compressive strength. The microstructure and elemental composition of the two materials are analyzed by SEM-EDS technology, and the elemental composition and lattice structure of geopolymer are analyzed by XRD technology. The strength formation mechanism of geopolymer materials is summarized. Finally, it is concluded that geopolymer-stabilized crushed stone meets the requirements of the specifications for road base materials and is expected to replace cement as a new type of green semi-rigid base material.