全固废地聚物隔离墙材料干湿循环耐久性研究OA

Conventional bentonite-,cement-and geopolymer-based cutoff walls suffer sharp rises in hydraulic conductivity during dry-wet cycling,compromising long-term performance.To address this problem,carbide slag(CS),red mud(RM),ground-granulated blast-furnace slag(GGBS)and silica fume(SF)are combined to fabricate four full-solid-waste geopolymer materials(CG,CGS,RCG,RCGS).Their basic properties and dry-wet durability are tested,and MIP/SEM-EDS are used to track pore-structure evolution and reveal durability mechanisms.After 7 days of curing,all four materials meet the anti-seepage design requirement for cement-based cutoff walls for unconfined compressive strength and hydraulic conductivity;the CG mix still meets the design requirements after ten dry-wet cycles,far outperforming conventional walls.The fraction of medium-to-large pores(≥50 nm)governs hydraulic-conductivity evolution,and keeping it≤5％effectively suppresses pore connectivity and the deterioration of anti-seepage performance.Mechanistic analysis shows that although the CS-RM co-activation system forms a denser early-age gel structure,the high water demand of SF increases shrinkage-swelling stress,and the inert RM particles cause stress concentration,jointly accelerating durability deterioration.In contrast,CS-only activation enables ongoing secondary hydration and crack self-sealing,refining the pore structure and minimizing durability degradation.The results guide rational design and engineering application of full-solid-waste geopolymer cutoff walls.