Effect of tartaric acid on hydration of a sodium-metasilicate-activated blend of calcium aluminate cement and fly ash F
Pyatina, T Sugama, T Moon, J James, S
Pyatina, T
Sugama, T
James, S
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Alternative Title
Abstract
An alkali-activated blend of aluminum cement and class F fly ash is an attractive solution for geothermal wells where cement is exposed to significant thermal shocks and aggressive environments. Set-control additives enable the safe cement placement in a well but may compromise its mechanical properties. This work evaluates the effect of a tartaric-acid set retarder on phase composition, microstructure, and strength development of a sodium-metasilicate-activated calcium aluminate/fly ash class F blend after curing at 85 °C, 200 °C or 300 °C. The hardened materials were characterized with X-ray diffraction, thermogravimetric analysis, X-ray computed tomography, and combined scanning electron microscopy/energy-dispersive X-ray spectroscopy and tested for mechanical strength. With increasing temperature, a higher number of phase transitions in non-retarded specimens was found as a result of fast cement hydration. The differences in the phase compositions were also attributed to tartaric acid interactions with metal ions released by the blend in retarded samples. The retarded samples showed higher total porosity but reduced percentage of large pores (above 500 ?m) and greater compressive strength after 300 °C curing. Mechanical properties of the set cements were not compromised by the retarder.
Keywords
C (programming language), Calcium, Calcium compounds, Cement additives, Compressive strength, Computerized tomography, Curing, Fly ash, Geothermal wells, Hydration, Mechanical properties, Metal ions, Metals, Microstructure, Phase composition, Scanning electron microscopy, Thermogravimetric analysis, X ray diffraction, X ray spectroscopy, Aggressive environment, Alkali activated cements, Attractive solutions, Calcium aluminate cement, Increasing temperatures, Retardation, Strength development, X-ray computed tomography, Cements
Source Title
Materials
Publisher
MDPI AG
Series/Report No.
Collections
Rights
Attribution 4.0 International
Date
2016
DOI
10.3390/ma9060422
Type
Article