Ceramics-Silikáty 53, (4) 276 - 282 (2009) |
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ALUMINOSILICATE POLYMERS - INFLUENCE OF ELEVATED TEMPERATURES, EFFLORESCENCE |
Škvára František 1, Kopecký Lubomír 2, Myšková Lenka 1,
Šmilauer Vít 2,
Alberovská Lucie 1,
Vinšová Lenka 1 |
1 Institute of Chemical Technology Prague, Department of Glass and Ceramics,
Technická 5, 166 28 Prague, Czech Republic
2 Czech Technical University in Prague, Faculty of Civil Engineering, Department of Structural Mechanics,
Thákurova 7, 16629 Prague, Czech Republic
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Keywords: Aluminosilicate polymer, Geopolymer, Efflorescence, Temperature |
Sodium is obviously bonded in the aluminosilicate polymer structure as Na(H₂O)n⁺ and not as Na⁺. The Na bond in the
aluminosilicate polymer structure is weak and this fact explains the tendency of aluminosilicate polymer material to the
formation of efflorescence in a humid environment. The strength values of the aluminosilicate polymer fired at temperatures
in the range of 200-1000°C attain their maximum at 200°C; they decline gradually afterwards. The aluminosilicate polymer
strength after firing is substantially higher than the residual strength of Portland cement. The Na bond in the structure suffers
a fundamental change and, starting from 600°C, the character of the Na bond is the same as that in vitreous materials. The
Na leaching declines in a very significant way after firing at temperatures above 600°C and the tendency to the formation
of efflorescence disappears. Aluminosilicate polymer materials exhibit excellent material properties. Nevertheless, there are
also some drawbacks associated with their application. They are, first of all, an easy leaching of alkaline components and
the formation of efflorescence. |
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