Towards Understanding the Rheological Properties of Slag-Cemented Paste Backfill

ABSTRACT

Ground Granulated Blast Furnace Slag (GGBS) has been increasingly used as replacement of Portland cement (PC) at different proportions in cemented paste backfill (CPB) material due to its relative low cost and sustainable utilization of the metallurgical slag. However, our understanding of the effect of adding GGBS to CPB on its flowability (defined by the rheological properties) is limited. Therefore, the aim of this study is to clarify and quantify the rheological properties of Slag-CPB and the key factors (e.g., transportation distance or time, temperature, mixing water quality, GGBS proportions) that affect them. Results show that curing time and temperature have a significant impact on the rheology of the Slag-CPB samples. Furthermore, the yield stress and viscosity of Slag-CPB are a function of its initial sodium chloride, GGBS and sulphate contents. It was also noticed that sulphate can inhibit, as well as activate the hydration of slag, depending on the slag’s initial content. Additionally, the rheological properties of Slag-CPB decreased when the concentration of sodium chloride increased. The results presented in this manuscript will provide a better understanding of the rheological properties of Slag-CPB and thus contribute to the better designing of Slag-CPB with optimal flowability and suitable mechanical stability.

KEYWORDS:

• Tailings
• rheological properties
• cemented paste backfill
• yield stress
• viscosity
• slag

Acknowledgments

The authors thank the Natural Sciences and Engineering Research Council (NSERC) of Canada and China Scholarship Council (CSC) for their financial support, and Lafarge Canada for providing the pozzolanic binder (blast furnace slag).

Disclosure statement

No potential conflict of interest was reported by the author(s).