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Open AccessArticle

Low-Carbon Binder for Cemented Paste Backfill: Flowability, Strength and Leaching Characteristics

1
College of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China
2
Science and Technology Innovation Center of Smart Water and Resource Environment, Northeastern University, Shenyang 110819, China
3
China Railway Construction Heavy Industry Co. Ltd., Changsha 410100, China
*
Author to whom correspondence should be addressed.
Minerals 2019, 9(11), 707; https://doi.org/10.3390/min9110707
Received: 5 September 2019 / Revised: 8 November 2019 / Accepted: 10 November 2019 / Published: 15 November 2019
(This article belongs to the Special Issue Alkali Activated Materials: Advances, Innovations, Future Trends)
Blast furnace slag was used as the main raw material to prepare the alkali activated slag (AAS), a low-carbon binder, for cemented paste backfill (CPB). The optimum parameters for preparing the AAS binders using an orthogonal experiment were obtained. Under the optimum conditions (NaOH content was 3 wt. %, Ordinary Portland cement (OPC) content was 7 wt. %, and gypsum dosage was 4 wt. %), the 28 days compressive strength of the binder was 29.55 MPa. The flow ability of the fresh CPB slurry decreased with solid content due to the increased yield stress, while the flow ability increased when rising the binder dosage. A predictive model for the compressive strength of CPB samples was reached through multivariate analysis and the R2 values were higher than 0.9. Sensitivity analysis showed that the solid content is the most important parameter which influences on the development of the CPB strength with a correlation coefficient of 0.826. From the Toxicity Characteristic Leaching Procedure (TCLP) tests, the leaching concentrations of Pb and Cd were below the threshold. As a result, the AAS has potential application as an alternative binder and cemented paste backfill. View Full-Text
Keywords: backfill; alkali activated slag; water film; compressive strength; TCLP backfill; alkali activated slag; water film; compressive strength; TCLP
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MDPI and ACS Style

Qiu, J.; Zhao, Y.; Long, H.; Guo, Z.; Xing, J.; Sun, X. Low-Carbon Binder for Cemented Paste Backfill: Flowability, Strength and Leaching Characteristics. Minerals 2019, 9, 707.

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