Hydration mechanisms of supersulfated cement: The role of alkali activator and calcium sulfate content

Considerable attention has been given to special cements, capable of reducing CO 2 emissions, energy and limestone consumption. Supersulfated cements are made of blast furnace slag (GBFS), calcium sulfate (CS), and small quantities of activator, but achieving their optimal proportions is complex. In...

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Bibliographic Details
Published in:Journal of thermal analysis and calorimetry 2018-11, Vol.134 (2), p.971-980
Main Authors: Rubert, S., Angulski da Luz, C., F. Varela, M. V., Pereira Filho, J. I., Hooton, R. D.
Format: Article
Language:English
Subjects:
Analytical Chemistry
Chemistry
Chemistry and Materials Science
Inorganic Chemistry
Measurement Science and Instrumentation
Physical Chemistry
Polymer Sciences
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Summary:Considerable attention has been given to special cements, capable of reducing CO 2 emissions, energy and limestone consumption. Supersulfated cements are made of blast furnace slag (GBFS), calcium sulfate (CS), and small quantities of activator, but achieving their optimal proportions is complex. In this paper, the effects of the both CS and alkali activator (KOH) contents were studied. The main results showed that the compressive strength, heat of hydration, and consumption of anhydrite phase were strongly influenced by the alkaline content, while low calcium sulfate or alkaline content increased the formation of CSH. The instability of ettringite was verified: with low CS, the probable hypothesis was its conversion into monosulfate due to the scarcity of sulfate; with high CS, it was associated with intense, rapid consumption of anhydrite with high KOH content, followed by the precipitation of ettringite on the surface of slag grains and its conversion into monosulfate.
ISSN:1388-6150
1588-2926
DOI:10.1007/s10973-018-7243-6