Relevance of SEM to long-term mechanical properties of cemented paste backfill

Niroshan, Naguleswaran, Yin, Ling, Sivakugan, Nagaratnam, and Veenstra, Ryan Llewellyn (2018) Relevance of SEM to long-term mechanical properties of cemented paste backfill. Geotechnical and Geological Engineering, 36 (4). pp. 2171-2187.

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Abstract

This paper is an attempt to relate the microstructure to long-term mechanical properties of the cemented paste backfill produced from a hard rock mine tailing from North Queensland in Australia bound with flyash-based geopolymer (geopolymer), flyash-blended cement (FBC), and general purpose cement (GPC). A relatively high slump (260 mm) paste backfill mix with 74 wt% solids has been used to prepare cylindrical paste backfill samples with a diameter of 50 mm and a height of 100 mm. The uniaxial compressive strength tests were conducted on all samples after curing for 112 days to obtain their strength, failure strain and Young's modulus. Fractured samples were examined under scanning electron microscope to understand the failure mechanisms at the microstructural scale. The results show that binders significantly affected the mechanical properties of paste backfills (ANOVA, p\0.05). The paste backfill bound with geopolymer gave the lowest strength and Young's modulus, while the paste backfills bounded with FBC and GPC showed comparable higher strength and modulus values. This was attributed to the relatively well-packed paste backfills with less cracks and smaller pore sizes in these paste backfills bound with FBC and GPC binders. In particular, needle-shaped particles, which were originally identified in GPC, highly influenced the mechanical property of paste backfills. These results indicate that fly ash can be used to partially replace the cement as a binder for paste backfills to achieve economic and environmental benefits.

Item ID: 52082
Item Type: Article (Refereed Research - C1)
Keywords: mine tailings, paste backfill, microstructure, scanning electron microscopy (SEM), uniaxial compressive strength (UCS), Young's modulus
Additional Information:

A version of this publication was included as Chapter 6 of the following PhD thesis: Niroshan, Naguleswaran (2018) Cemented paste backfill modification using different types of binders and insight into its mechanical, micro-structure, and flow properties. PhD thesis, James Cook University, which is available Open Access in ResearchOnline@JCU. Please see the Related URLs for access.

ISSN: 1573-1529
Date Deposited: 23 Jan 2018 01:40
FoR Codes: 09 ENGINEERING > 0905 Civil Engineering > 090501 Civil Geotechnical Engineering @ 100%
SEO Codes: 87 CONSTRUCTION > 8702 Construction Design > 870201 Civil Construction Design @ 100%
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