Akademik Veri Yönetim Sistemi
3rd International Conference on Opencast Mining Technology & Sustainability, Singrauli, Hindistan, 22 - 23 Ocak 2021, ss.30-40
Abstract —The
use of coal mining wastes (e.g., fly ash) in the construction materials are
poor to effectively manage such high amounts of existing and ever-increasing
wastes. Hence, there is an urgent need to search for alternate techniques or
ways to reuse/recycle and hence lessen the surface discharged amounts of coal
wastes. In this study, cemented coal fly ash backfill
(CCB) was utilized as a ground support element in a Turkish lignite coal mine. To
reduce the cement-related costs, CCB samples were prepared by using a fly ash
content of 75%, 77.5%, and 80% as a function of curing time (2, 7, 28, and 90
days). The fresh (e.g., slump and setting time) and
hardened (e.g., compressive strength and mercury porosity) geotechnical
properties of CCB samples were investigated in the laboratory. Results illustrate
that, at a constant slump value (20 cm), the backfill containing
a fly ash content of 75%, 77.5%, and 80% provided a water/cement (w/c) ratio of 0.99, 1.08, 1.19. The w/c ratio of CCB increases
from 0.99 to 1.19 due to the decreased cement amount (25% to 20%) which led to
the strength reduction of backfill formulated with high amounts of fly ash. Finally, understanding the geotechnical properties of CCB mix
still remains critical for the ultimate design of an effective and efficient CCB
material for underground mines.
Keywords—cemented
coal fly ash backfill; setting times; slump; water/cement ratio; compressive
strength; porosity