Durability of CO<sub>2</sub>-fly ash-based backfill materials in cation water deterioration
Ichhuy Ngo, Liqiang Ma, Jiangtao Zhai, Yangyang Wang, Tianxiang Wei
Abstract
This study aims to investigate the weakening of CO2-fly ash-based backfill (CFBF) material in cation water. Weakening is determined in an order of Na+ > Ca2+ > Mg2+ by slake durability and mechanical properties analysis. Na+ damages the microstructure of CFBF through the ion exchange phenomenon, causing the ejection of tetrahedral calcium. In Ca2+ and Mg2+ water, N-M-A-S-H gel is precipitated and filled in openings via a two electrical-layer mechanism, which mitigates the materials from further deterioration. On this basis, the suitable cation type and concentration range are proposed as criteria to implement CFBF in mine-water affected backfill coal mining.
Topics & Concepts
Fly ashDurabilityMicrostructureMaterials scienceGeotechnical engineeringIon exchangeEnvironmental scienceMetallurgyMineralogyMining engineeringIonGeologyChemistryComposite materialOrganic chemistryRock Mechanics and ModelingTailings Management and PropertiesConcrete and Cement Materials Research