Experimental Investigation into the Mechanical Properties of Fine-Grained Tailings After Cemented Modification

Fine-grained tailings pose significant challenges for direct resource utilization applications such as tailings dam construction and backfill preparation due to their fine particle size, high specific surface area, and extended natural consolidation period. This investigation examined the mechanical properties of cemented fine-grained tailings under varying mix proportions and conditions. The cemented tailings were prepared using raw tailings material containing approximately 95% particles sized 0-74 μm. A comprehensive experimental program comprising 36 flexural tests and uniaxial compressive tests was conducted, with cement-sand ratio (A), curing age (B), and specimen immersion time (C) as controlled variables. The strength development mechanism was characterized through XRD and SEM, while mechanical performance data were systematically analyzed using range analysis, ANOVA, and regression analysis. Key findings demonstrate that ① the flexural strength of cemented tailings ranged from 0.43 to 2.07 MPa, with compressive strength varying between 3.02 and 12.52 MPa; ② both compressive and flexural strengths exhibited positive correlations with factors A and B, while showing negative correlation with factor C; ③ hydration products consisted primarily of C-S-H gels and zeolite-like phases, whose interwoven microstructure collectively ensured specimen integrity; ④ all three factors significantly influenced mechanical strengths with identical hierarchical impact: A > B > C; and ⑤ a comprehensive predictive model based on ternary quadratic polynomial regression was developed and validated. These results provide a scientific foundation for sustainable resource utilization of fine-grained tailings as solid waste materials.