Effects of industrial solid wastes on the rheological behavior and electrical resistivity-acoustic emission responses of cement-based grouted bodies under loading

Industrial solid waste-modified cement grouts provide a promising pathway for reducing cement consumption and promoting waste utilization, yet comparative evidence remains limited on how different wastes influence mechanical performance and non-destructive indicators under the same loading framework. This study investigates cement-based grouted bodies modified with fly ash (FA), S95 slag powder (SP), or coal gangue powder (CG) across water-cement ratios (W/C = 0.5-0.9) and replacement levels (0-40%). Slurry viscosity and grouted-body formation ratio were measured, and specimens were tested under monotonic uniaxial compression with synchronized monitoring of compressive strength, electrical resistivity, acoustic emission (AE), and wave velocity. Increasing W/C consistently reduced formation ratio, strength, and wave velocity. At a fixed W/C, SP generally improved strength at moderate replacement (20-30%), FA maintained near-reference strength mainly at 10-20%, whereas CG predominantly decreased strength, particularly at ≥30%. Loading-induced electro-mechanical responses were waste-dependent: resistivity at peak load (ρ_max) showed the strongest association with strength for FA and SP systems, while cumulative AE ring count (CRC) was more informative for CG. An eco-efficiency proxy further indicated diminishing strength return per unit replacement with increasing replacement level, with SP exhibiting comparatively higher efficiency at low-to-moderate replacement.