Study on mix ratio optimization, microstructure evolution, and economic benefits of iron tailings-fly ash-limestone powder ternary geopolymer

作者：Kun Huang, Kun Huang, Yunhan Jiang, Guojun Cai, Ruifeng Chen, Zhaolin Li, Kai Huang, Kai Huang, Lulu Liu, Xixi Huang · 发表于：Journal of Cleaner Production · 年份：2026 · DOI：10.1016/j.jclepro.2026.147514 · 被引用次数：6 · 研究领域：Concrete and Cement Materials Research、Magnesium Oxide Properties and Applications、Microbial Applications in Construction Materials

Iron ore tailings (IOT) can be synergistically combined with other solid wastes under alkaline conditions to form eco-friendly cementitious materials. This study synthesized a ternary geopolymer using sodium silicate (Na 2 SiO 3 ) and sodium hydroxide (NaOH) as a composite alkali activator, along with IOT, fly ash (FA), and limestone powder (LSP) as precursors. We systematically examined the effects of activator modulus ( M ), alkali-to-precursor ratio ( A / P ), water-to-binder ratio ( W / B ), and FA replacement ratio ( ω ) on mechanical performance through orthogonal design and single-factor testing. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analysis were employed to characterize the microstructure, pore features, and alkali-activation mechanism. A cost comparison between the developed geopolymer and ordinary Portland cement (OPC) was also performed. Orthogonal test results revealed the following order of factor significance on strength: M > ω > A / P > W / B , with optimal levels of M = 1.2, A / P = 0.38, W / B = 0.26, and ω = 30 %. In single-factor tests, strength increased nonlinearly with extended curing time and reduced alkali modulus. A low-modulus activator ( M = 1.0) created a highly alkaline environment that accelerated the dissolution of reactive Si-Al components from FA/IOT and calcium from LSP. Interactions among these dissolved species promoted C-(A)-S-H gel for...