关键词: 黄金尾矿　, 混凝土　, 处理方式　, 抗压强度　, 孔隙结构　, 内养护

Abstract: To achieve the large-scale and high-value-added utilization of gold tailings (GTs) and to avoid the high ener gy consumption associated with conventional drying pretreatment,this study proposes the use of pre-wetted GTs as a partial re placement for fly ash in the preparation of ordinary concrete.Four mixtures were designed,including a control group,a dry GTs group,a dry GTs with compensatory water group,and a pre-wetted GTs group,all with a water-to-binder ratio of 0.29.The effects of the three GTs treatment methods on the fresh properties,mechanical properties,autogenous shrinkage,chloride ion permeability,and microstructure of concrete were systematically compared.In addition,X-ray diffraction (XRD),thermogravi metric analysis (TGA),and nanoindentation were employed to reveal the internal curing mechanism.The results indicate that the pre-wetted GTs group (GT-p) exhibited increases in compressive strength of 6.4%,8.8%,and 9.0% at 3 d,7 d,and 28 d,respectively,compared with the control group,while reducing autogenous shrinkage by 15.8% and the total charge passed by 4.6% at 28 d.Furthermore,the pore structure was significantly refined (with fewer harmful pores and more gel pores),and the microscopic elastic modulus was increased by 12.40%.Mechanism analysis confirms that the pre-wetted GTs (with a 12-h wa ter absorption of 20.1%) continuously release water during cement hydration,maintaining a higher internal relative humidity in the paste,effectively mitigating the self-desiccation effect,and promoting the formation of hydration products and the deposition of C-S-H gel,thereby optimizing the interfacial transition zone and matrix densification.Meanwhile,the GT-p group achieved the highest eco-efficiency and cost-effectiveness,balancing environmental and economic benefits. In summary,the use of pre wetted GTs as a replacement for fly ash in concrete production represents a technical route featuring high performance,low cost,and low carbon emissions,providing a reliable theoretical basis and engineering reference for the large-scale resource utili zation of GTs.