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Gypsum-Free Portland Cement Pastes of Low Water-to-Cement Rat10

Published online by Cambridge University Press:  21 February 2011

FrantiŠek ŠkvÁra
FrantiŠek ŠkvÁra*
Affiliation:
Institute of Chemical Technology, Department of Glass and Ceramics Technology 5, 16628 Prague 6, Czech Republic
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Abstract

Gypsum-free portland cement is a low porosity hydraulic binder based on finely groundportland cement clinker with addition of synergetic system containing an anion-active surface active agent (usually a sulphonated polyelectrolyte) and an inorganic salt (usually sodium carbonate) for regulation of the hardening process. The properties of GF cement are different from ordinary portland cement; they display, for example, higher strength, better corrosion resistance and thermal stability. These positive differences arise from the different mineralogy and microstructure of the hydration products, for example the absence of portlandite crystals. The main component of the binder product in hardened GF cement pastes is C-S-H (mean C/S ratio 2.7, based on EDAX analysis) intergrown with very fine Ca(OH)2 and highly dispersed C-A-H phases (hexagonal and cubic). The absence of crystalline formations in the GF hardened pastes is responsible for highermechanical strength. In the Czech Republic, GF cement is produced in the cement works of CEVA Prachovice Inc. ( Holderbank group) and is used for special works in the building industry.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 370: Symposia Va/Vb – Microstructure of Cement-Based Systems/Bonding and Interfaces in Cement... , 1994 , 153
Copyright
Copyright © Materials Research Society 1995

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