Publikace (přehled)

This work describes the role of chemical composition and curing conditions on the geopolymer’s strength, leachability of chemical elements and porosity. The study focuses on the geopolmer material prepared from calcined kaolinite claystone, which is not studied frequently as a raw material for the geopolmer production, although it has high application potential as it is easily commercially available and allows preparation of geopolymers with low viscosity. 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 density of water glass in the range of 1.2 to 1.6 g.cm-3. Geopolymers were cured at temperature within the range from 5°C to 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 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.