The objective of this study was to determine the structural and textural description of municipal solid waste incineration (MSWI) bottom ash that was subjected to a six-month seasoning process. Bottom ash samples, with a particle size fraction of 0.063–0.1 mm, were seasoned in a closed landfill and collected for laboratory analyses at monthly intervals. The research focused on determining the structural parameters, using methods such as nuclear magnetic resonance spectroscopy (¹H NMR), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), and the textural parameters, using low-pressure nitrogen adsorption (LPNA) at −196.15 °C. The analyses of the porous structure of the bottom ash samples revealed differences in texture of ASH 1 to ASH 6, specifically in the pore volume (micro- and mesopores), specific surface area, and pore size distribution. Changes in the structural and porous characteristics of the samples were attributed to the duration of the seasoning process. The results of the structural analysis of the bottom ash suggest its application in the concrete industry, potentially enhancing the long-term mechanical strength of concrete. The results of the textural analysis indicate the possible use of MSWI bottom ash in environmental applications, as the internal surface area could be further developed.

Slags and ashes generated in thermal waste treatment facilities require proper management. In line with the principles of the circular economy, new, more economical, and ecological possibilities for utilizing these substances are sought. These waste materials exhibit characteristics similar to rocks in many aspects. This study focuses on analyzing the similarities and differences between nine selected rocks and three samples of slags and ashes obtained from municipal waste incineration. The main research device used was a polarizing microscope, using reflected, transmitted, and fluorescent light. Additionally, low-pressure gas adsorption equipment, as well as helium and quasi-liquid pycnometers, were used for complementary analysis. The parameters analyzed mainly covered broadly defined petrographic properties of rocks and slags, with a particular emphasis on porosity, porous structure, and the spatial distribution of pores and fractures. The conducted analyses confirmed a significant similarity between slags and ashes and clastic sedimentary rocks such as sandstones and mudstones. The research results underscore the importance of petrographic microscopic studies for analyzing materials other than rocks. They also allow for exploring applications for slags and ashes in areas traditionally reserved for natural rock resources. The findings also indicate the necessity of using methods other than microscopic ones to describe the pore space of rocks. The lower measurement range of the optical microscope is limited to approximately 1 μm, covering only macropores. Other methods extend this characteristic to micro- and mesopores. Therefore, a combination of different methods is often employed to obtain a more comprehensive characterization of rock porosity.

The aim of this research was to measure the filtration properties of waste coal ash under the influence of hydrostatic pressure generated in a three-axial compression apparatus. The scope of work included determining the compactibility parameters, maximum bulk density and optimal moisture content. Permeability tests were performed for a sample with an average grain composition at three compaction indices $I_S$: 0.964, 0.98 and 1.00. The hydrostatic pressure ranging from 0.5 to 1.8 bar corresponded to the layer depths from 2.17 to 7.83 m. Gradually increasing the pressure during the first loading cycle caused irreversible changes in the structure of the sample by local material agglomeration or grain interlocking. The water permeability coefficient was higher in the second loading cycle than in the first cycle. It was shown that waste coal ash cannot be used as a construction material on its own. To obtain constant filtration properties, the waste coal ash material should be doped, or an optimal compactionshould be used ($I_S$ = 1.00). The results presented in this study are important for assessing the use of waste coal ash for construction engineering purposes.

The aim of this study was to analyze properties of natural and waste-containing porous materials intended for use in construction. Experiments using the hydrostatic buoyancy method were conducted to assess the fundamental characteristics of studied samples that include bulk density, porosity, and water absorption. The investigation focused on the behavior of both natural and laboratory-prepared porous materials subjected to water absorbability measurement. The time required for complete saturation process with water was determined, together with the minimum saturation time that still ensured satisfactory measurement accuracy. For composite-cement stones, the results of bulk density measurements and the characterization of pore space, including total, open, and isolated porosity, were analyzed. Based on the findings, practical recommendations were proposed regarding the displacement procedure and the interpretation of results obtained during the determination of absorbability of materials with complex internal structures. The conclusions drawn from the research conducted are crucial for environmental protection, as they contribute to better characterization and assessment of the quality of products with a smaller negative impact on the planet.

In this work, the results of ellipsometric studies of bilayer films of broadband oxides (Al₂O₃:ZnO, Al₂O₃:TiO₂) are presented. Thin layers of ${\mathrm{A}\mathrm{l}}_2{\mathrm{O}}_3,\mathrm{Z}\mathrm{n}\mathrm{O}$ and $\mathrm{T}\mathrm{i}{\mathrm{O}}_2$ were deposited on silicon substrate using the atomic layer deposition (ALD) method. The desired ranges of antireflective properties were selected, and then, based on optical modeling, the appropriate thicknesses of individual layers were determined. Optical constants were determined based on ellipsometric measurements in the spectral range of 193–1690 nm. For several selected samples, this range has been extended to 470–6500 cm⁻¹. B-spline function, Tauc–Lorentz, Cody–Lorentz and Psemi-M0 oscillator models were used to describe the optical properties of the investigated films. Reflectance spectra for layers on a silicon substrate were determined in the range from 200 to 2500 nm. Additionally, complementary studies, SEM and EDS analyses, were also performed. The EDS investigations enabled the determination of the composition of the bilayer films. Spectrophotometric analysis demonstrated consistency between the obtained experimental data and theoretical predictions, confirming the validity of the applied model. The studies showed significant improvement in antireflective properties depending on the thickness of the prepared layers while maintaining an extinction coefficient close to zero, across much of the investigated spectral range, regardless of the layer thickness.

The growing demand for sustainable and circular construction materials has increased interest in reusing by-products from municipal solid waste incineration. Due to the variability in the chemical composition of bottom ash (BA) between different plants, sampling seasons, and particle sizes, an individualized approach depending on its origin is essential. This study examines the potential of BA as a binding material in composite structures. Composites were prepared from BA fractions of different granulometries, including ground and thermally treated material. Compressive strength tests and structural analyses of density, porosity, and water permeability were performed to evaluate the influence of particle size and heat treatment on binding activity. The results show that smaller particle sizes significantly improved compressive strength, while the highest strength was obtained for samples calcined at 1000 °C, with an average increase of 84% compared to untreated material. Thermal treatment enhanced binding activity through the mobilization of hydration-active compounds bound in non-reactive mineral phases formed during water cooling and also increased water permeability due to the breakdown of porous structures. These findings confirm the potential of BA as a secondary binder in construction materials; however, further research is needed to improve its reactivity and mechanical performance.