Comprehensive Performance Evaluation of Lead–Zinc-Tailing-Based Geopolymer-Stabilized Aggregates

As an innovative inorganic cementitious material, geopolymer holds significant application potential in the field of road engineering. Based on the theoretical basis of industrial solid waste resource utilization and combined with geopolymerization technology, this study investigates the feasibility of applying lead–zinc-tailing-based geopolymer–stabilized aggregate (LZT-GSA) in road engineering through systematic mechanical property tests, durability assessment, and microstructural characterization. The study focuses on the influence of cementitious material admixture on the unconfined compressive strength, splitting tensile strength, compressive resilient modulus, drying shrinkage, and freeze–thaw cycle resistance of LZT-GSA. The experimental results demonstrated that LZT-GSA exhibited excellent properties in terms of mechanical performance and durability, which were remarkably better than those of conventional cement-stabilized aggregates (CSA). However, the incorporation of a small amount of lead–zinc tailing alone can weaken the mechanical properties of CSA. The drying shrinkage of LZT-GSA was slightly higher than that of CSA due to the difference in the intrinsic reaction mechanism between LZT-GSA and CSA. The effective cementing and wrapping effect of geopolymer gel on discrete aggregate dramatically improves the structural compactness of LZT-GSA. The leaching concentration of heavy metals in LZT-GSA is far below the requirements of environmental protection standards. These research results not only provide theoretical support for the resource utilization of lead–zinc tailings, but also lay a technical foundation for its practical application in road engineering.