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.

A metakaolinite-based geopolymer binder was prepared by using calcined claystone as the main raw material and potassium as the alkaline activator. Chamotte was added (65 vol%) to form geopolymer composites. Potassium hydroxide (KOH) was used to adjust the molar ratio of K/Al and the effect of K/Al on thermo-mechanical properties of geopolymer composites was investigated. This study aimed to analyze the effect of K/Al ratio and exposure to high temperatures (up to 1200 °C) on the compressive and flexural strengths, phase composition, pore size distribution, and thermal dilatation. With an increasing K/Al ratio, the crystallization temperature of the new phases (leucite and kalsilite) decreased. Increasing content of K/Al led to a decline in the onset temperature of the major shrinkage. The average pore size slightly increased with increasing K/Al ratio at laboratory temperature. Mechanical properties of geopolymer composites showed degradation with the increase of the K/Al ratio. The exception was the local maximum at a K/Al ratio equal to one. The results showed that the compressive strength decreases with increasing temperature. For thermal applications above 600 °C, it is better to use samples with lower K/Al ratios (0.55 or 0.70).

Geopolymer foam is classified as a lightweight material with high porous in its matrix which has great offer for applications requiring fire-resistant, thermal, and acoustic properties. However, the high sensitivity to humid environments can be a major barrier of geopolymer foam that limits the variety of applications of this material. Based on this drawback, two types of hydrophobic agent (Lukosil M130 and Lukofob ELX) were used as an impregnator to treat the surface of geopolymer foam samples. This paper presented the results of water absorption properties of the untreated and treated geopolymer foam composites. The obtained properties were flexural strength, compressive strength, density, total water absorption, the rate of water absorption, and water absorption coefficient. The results showed that the samples after being impregnated with hydrophobic agents improved significantly their waterproof property especially using Lukosil M130. Moreover, the samples treated with Lukosil M130 had positive impact on their mechanical strength.

The aim of this paper is investigation of the photocatalytic properties of TiO₂ thin films prepared by PECVD with metal nanoparticles built‐up on the film surface. The deposition of TiO₂ films was carried out in the radio frequency (RF) low‐pressure PECVD reactor. Layers were deposited at two different substrate temperatures (40 and 300 °C). The surface of TiO₂ films was subsequently covered by noble metal nanoparticles—silver, platinum, and gold, deposited by different methods. For determination of the photocatalytic decomposition the Acid orange 7 (AO7) C₁₆H₁₁N₂NaO₄S organic dye was used. Selected samples were used for antibacterial tests (Gram‐negative bacteria Escherichia coli). The results clearly proved that presence of metal clusters resulted in enhancement of the photocatalytic and antibacterial activity.