Research Article

Effects of Fine Gangue on Strength, Resistivity, and Microscopic Properties of Cemented Coal Gangue Backfill for Coal Mining

Table 1

Chemical composition and physical properties of the materials used.

Major elementCement (%)Fly ash (%)Gangue (%)

SiO222.2752.4228.46
Al2O35.5932.4816.11
Fe2O33.473.6210.86
CaO65.903.057.15
MgO0.811.013.50
TiO21.260.80
Specific gravity (g/cm3)3.12.22.0
Specific surface (m2/kg)349415499
Fineness (>45 µm) (%)542.5453.78
Moisture content (%)0.568.0
Loss on ignition (%)23.8

Notes: for measuring SiO2, samples were first burned at 800°C to remove organic matter and then measured in a NaOH solution at 650°C. All other oxides were measured from samples subject to sealed digestion in HF + HNO3 at 185°C.