Abstract
In the Abitibi‑Témiscamingue region’s mining sector in Canada, underground mines utilize cemented paste backfill (CPB) for secondary ground support. The conventional CPB formulation employs a binder known as the reference binder (RB), consisting of 20% general use Portland cement (GU) and 80% ground granulated blast furnace slag (GGBFS). This reference binder (RB = 20GU/80GGBFS) demonstrates excellent mechanical and hydro-geotechnical properties for CPB. However, its high cost, limited availability of GGBFS, and the environmental impact associated with GU production highlight the critical need for research into alternative, cost-effective, and environmentally friendly binders.
This study explores the use of electrical arc furnace slag (EAFS) and circulating dry scrubber dust (CDSD) from the steelmaking industry to partially replace GGBFS and act as a substitute for type GU cement. The EAFS undergoes a processing stage involving screening and grinding, resulting in a product termed ground EAFS (GEAFS). Various formulations of the ternary blended binder GGBFS/GEAFS/CDSD are evaluated for their unconfined compressive strength (UCS) at 7 and 28 days to assess their suitability as binders for CPB.
The result of this study demonstrates the feasibility of completely replacing type GU cement and substituting up to 30% of GGBFS in the reference binder (RB) without compromising the UCS at 28 days (UCS28d). These highly promising findings suggest the potential to lower the cost and carbon footprint of CPB while promoting the recycling of metallurgical waste within the mining industry, aligning with a circular economy approach.