Journal Published Online: 06 December 2019
Volume 43, Issue 5

Hydration Effects on Specific Gravity and Void Ratio of Cemented Paste Backfill

CODEN: GTJODJ

Abstract

This article presents the results of a laboratory study on the variation of specific gravity (Gs) and void ratio (e) in a cemented paste backfill (CPB) with different cement contents and curing times. CPBs consist of a mixture of mine tailings, portland cement, and mine process water. In this study, a helium stereopycnometer device was used to determine Gs for specimens having cement contents of 3.0, 5.3, 7.5, and 11.1 % by the weight of dry tailings. Curing times of 4 h, 1, 3, 7, 14, and 28 days were considered for testing purposes. In total, 240 helium stereopycnometer tests were conducted in this study, which shows that Gs decreases in the CPB specimens as specimens cure over time and the cement hydrates. Furthermore, 96 tests were conducted to determine e of the CPB specimens with different combinations of cement contents and curing times. The results of these tests indicate that similar to Gs, e decreases with an increase in curing time as the specimens hydrate. The reduction in Gs and e is attributed to the formation of hydration products, which have a lower density than the cement and fill the void space between the particles. The results show that the variation of Gs that is due to the hydration process should be considered in the calculation of e; otherwise, this physical property, especially for specimens with high cement contents, is overestimated.

Author Information

Jafari, Mohammadamin
Department of Civil and Mineral Engineering, University of Toronto, Toronto, ON, Canada
Shahsavari, Mohammad
Department of Civil and Mineral Engineering, University of Toronto, Toronto, ON, Canada
Grabinsky, Murray
Department of Civil and Mineral Engineering, University of Toronto, Toronto, ON, Canada
Pages: 17
Price: $25.00
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Details
Stock #: GTJ20190094
ISSN: 0149-6115
DOI: 10.1520/GTJ20190094