Results
Slag-bound paste had lower yield stress and plastic viscosity than the Portland-cement comparison. Both increased over time. Finer slag and higher temperatures increased these measures; higher silicate modulus reduced them.
How it was tested
The authors prepared 20 alkali-activated slag mixtures using gold-mine tailings, distilled water and a 16% activator dosage. Rheometer measurements were taken immediately after mixing and at 0.5, 1 and 2 hours. A Bingham model was fitted to the measurements.
Study limits
The authors state that testing was limited to laboratory rheology. Section 3.1 describes lower early yield stress and viscosity when binder content rose from 6% to 8%; the conclusion instead describes a decrease beyond 8%. These statements are inconsistent.
Further work proposed
The authors propose investigating paste–rock interactions under placement and curing conditions, including applied stress. They also recommend considering flow behaviour alongside strength when choosing slag fineness.
Original sources
Yunpeng Kou; Haiqiang Jiang; Lei Ren; Erol Yilmaz; Yuanhui Li (2020). Rheological Properties of Cemented Paste Backfill with Alkali-Activated Slag.