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Preparation and performance of composite activated slag-based binder for cemented paste backfill
Faguang Yang1, Fan Wu2, Baogui Yang1
1School of Energy and Mining Engineering, China University of Mining & Technology (Beijing), Beijing, 100083, China.
Chemosphere
|October 1, 2022
Summary
A novel composite activated slag-based binder (CASB) effectively replaces ordinary portland cement (OPC) in cemented paste backfill. This sustainable binder utilizes industrial byproducts, reducing costs and immobilizing heavy metals.
Area of Science:
- Materials Science
- Chemical Engineering
- Environmental Science
Background:
- Ordinary portland cement (OPC) use in cemented paste backfill (CPB) is costly and environmentally impactful.
- Blast furnace slag (BFS) and fly ash (FA) are abundant industrial byproducts with potential for cement replacement.
Purpose of the Study:
- To develop and characterize a novel composite activated slag-based binder (CASB) as a sustainable alternative to OPC for CPB.
- To optimize the CASB composition and investigate its hydration mechanism, mechanical properties, and environmental benefits.
Main Methods:
- Orthogonal experimental design and efficacy coefficient method for CASB ratio optimization.
- X-ray Diffraction (XRD), Thermogravimetric (TG), and Scanning Electron Microscopy (SEM) for hydration product analysis.
- Compressive strength testing and rheological property evaluation of CASB-CPB under various conditions.
Main Results:
- Optimum CASB ratio determined as 15:12:13:60 (FA: CC: DG: BFS).
- CASB hydration involves coupled alkali-sulfate activation, yielding C-S-H gels and ettringite (AFt).
- Increased mass concentration improved compressive strength but reduced slurry flowability; CASB reduced filling costs and immobilized heavy metals.
Conclusions:
- CASB is a viable, cost-effective, and eco-friendly alternative binder for CPB.
- This research promotes solid waste utilization and enhances the economic and ecological benefits of mining operations.
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