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Minerals 2018, 8(10), 444;

Kaolinite Claystone-Based Geopolymer Materials: Effect of Chemical Composition and Curing Conditions

Unipetrol Centre for Research and Education, Revoluční 84, 400 01 Ústí nad Labem, Czech Republic
Received: 24 August 2018 / Revised: 25 September 2018 / Accepted: 3 October 2018 / Published: 11 October 2018
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This work describes the role of chemical composition and curing conditions in geopolymer strength, leachability of chemical elements and porosity. The study focuses on geopolymer material prepared from calcined kaolinite claystone, which is not studied frequently as a raw material for geopolymer production, although it has a high application potential as it is easily commercially available and allows preparation of geopolymers with low viscosity. The composition of geopolymers and their curing methods were selected considering their ease of use in the praxis. Therefore, the potassium water glass itself was used as alkali activator without any KOH or NaOH addition. Chemical composition was changed only by the density of water glass in the range of 1.2 to 1.6 g·cm−3. Geopolymers were cured at a temperature within the range of 5 °C–70 °C to speed up the solidification process as well as by microwave radiation. High compressive strengths were obtained for geopolymers with the highest densities of the water glass (1.5 and 1.6 g·cm−3) in dependence on various curing conditions. Higher strengths were achieved in the case of samples where the solidification was not accelerated. The samples cured at lower temperatures (5 °C) showed lower porosity compared to the other curing types. The lowest leachability of Si and alkalis was reached for the samples with water glass density 1.5 g·cm−3. View Full-Text
Keywords: geopolymer; claystone; leachability; compressive strength; porosity geopolymer; claystone; leachability; compressive strength; porosity

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Hájková, P. Kaolinite Claystone-Based Geopolymer Materials: Effect of Chemical Composition and Curing Conditions. Minerals 2018, 8, 444.

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