DOI: 10.11799/ce202512026
Influence law of sulfate ion concentration on the strength of coal gangue-based filling material
XIA Junwu
WANG Yujing
CHEN Guohua
SONG Kangjia
Abstract：Given the challenges in quantitatively analyzing complex ionic species within high-salinity mine water and the dominance of SO42-in both concentration and material erosivity,we investigated the effect of SO42-concentration on the mechanical behavior of coal gangue-based filling materials.We prepared specimens using coal gangue and simulated mine water(sodium sulfate solution at 0-30000 mg/L SO42-)as core components,adding a curing agent for consolidation,then tested compressive strength and performed SEM microscopy across curing ages.Results demonstrate that during days 1～7,moderate SO42-boosts strength whereas excess concentrations weaken it,and by days 14～28,the 30000 mg/L SO42-group achieves optimal enhancement;SEM imaging at 28 days reveals escalating SO42-concentrations drive denser interlaced networks of ettringite crystals and C-S-H gels while visibly reducing pores,aligning consistently with macroscopic strength progression.Specimens fabricated with sodium sulfate solution outperform tap-water counterparts in compressive strength,confirming the feasibility of the dual-waste filling material.
Keywords：filling materialssodium sulfate solutioncoal ganguesulfate ioncompressive strength
Publication Date：2025-12-20
Online Publishing Date：2026-01-29(First online date of this platform, not the publication date of the document)
Pages：7( 203-209 )