In the context of intensified construction and stricter requirements for the energy efficiency of buildings, the use of thermal insulation materials and technologies is becoming particularly important. One promising area in this field is the use of thermal insulation mixtures, which are versatile, adaptable, and highly reliable in operation. Mixtures based on fillers with a porous structure and materials that impart thermal insulation properties, which provide higher thermal insulation properties, are of great interest. However, the development of dry thermal insulation mixtures is hampered by insufficient study of their physical, mechanical, and operational characteristics. This article presents the results of research work on the development and study of dry building thermal insulation mixtures. A distinctive feature of the work is the creation of a composition of dry building thermal insulation mixtures based on local raw materials, such as diatomite, its thermal modification at a temperature of 900 °C, the use of expanded perlite sand, lime, and Portland cement. Research into the properties of modified diatomite has shown that its surface after thermal treatment differs from the surface of unburned diatomite in that it becomes more active and has a 3–4 times higher increase in strength. Modified diatomite and expanded perlite sand have low thermal conductivity, and this property was used in the creation of building thermal insulation mixtures, which was confirmed by research, as the thermal conductivity coefficient ranged from 0.128 to 0.152 W/m °C. The developed dry thermal insulation lime–cement mixture is intended for both interior and exterior finishing works, which is confirmed by the results obtained for determining the frost resistance of the solution and the frost resistance of the contact zone, and corresponds to the F35 grade and has a strength of up to 3.59 MPa.

Marbleized limestone processing waste (MLPW) was used as the primary raw material in this study. White Portland cement (CEM I 52.5, M500) and gray Portland cement (CEM I 42.5, M450) were employed as binders. The mixtures were prepared with an MLPW content ranging from 70 to 85 wt.% while maintaining a constant water-to-cement ratio (w/c) of 0.25. The specimens were manufactured by hyperpressing under compaction loads of 200 and 300 kN and subsequently cured for 7 days in a sealed moist environment. Specimens compacted at 200 kN achieved compressive strengths corresponding to brick strength grades M350 and M400. Increasing the compaction load to 300 kN resulted in specimens meeting the requirements of strength grades M400 and M500. When gray Portland cement (M450) was used as the binder at identical MLPW contents and water-to-cement ratio, specimens compacted at 300 kN attained compressive strengths corresponding to grades M400 and M450. The mechanical performance of the hyperpressed bricks produced with both white and gray Portland cement correlated well with the microstructural characteristics observed by scanning electron microscopy (SEM). The average density of all specimens exceeded 2100 kg/m³, allowing the developed materials to be classified as heavyweight concrete. The study aims to develop optimized compositions and a manufacturing technology for hyperpressed bricks based on marbleized limestone processing waste, thereby promoting the sustainable utilization of industrial by-products in the production of high-performance masonry materials.

For the experimental studies, waste from the processing of marbleized limestone (MLPW) was used as the primary raw material. White Portland cement M500 was employed as the binder. Inorganic red, green, and blue pigments were used to produce colored products. The specimens were moulded under a compaction force of 300 kN. The products were cured for 7 days in a water-curing environment. After 7 days of water curing (tested at the total age of 9 days), the compressive strength of the specimens ranged from 48.3 to 53.8 MPa, corresponding to a high early-age strength level typically associated with brick grades M450–M500. The results of the experimental studies indicate that the incorporation of pigments at dosages of 3.5–6.5% enables the production of colored hyperpressed bricks without a substantial change in their average density; however, it has a noticeable effect on their strength characteristics. For all pigments investigated, the highest mean strength values were obtained at a pigment content of 5%, whereas a further increase in the dosage to 6.5% was accompanied by a reduction in the mean strength. The microstructure of the investigated specimens was characterised by a predominantly dense and heterogeneous structure consisting of a cement matrix, mineral particles of MLPW of various sizes, pores, and microcracks. Fine inclusions morphologically distinct from the surrounding phase were observed within the cement matrix and were presumed to correspond to the incorporated pigments. Energy-dispersive X-ray spectroscopy (EDS) was performed to determine their elemental composition and assess the distribution of the pigment components. The aim of this study was to develop compositions and a manufacturing technology for colored hyperpressed bricks based on waste from the processing of marbleized limestone.

This paper presents a study of thermal-insulating dry-mix mortars containing shell limestone, shell limestone extraction waste, and hollow microspheres. The effects of shell limestone and fillers on physical, mechanical, and thermal properties were investigated. The microstructure of shell limestone was examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) using a JEOL JSM-7000F scanning electron microscope. The elemental mass fractions confirmed the carbonate nature of the shell limestone raw material (wt.%: O, 50.3–43.7; Ca, 34.1–44.2; C, 15.6–12.1). Finely dispersed fillers, hollow glass microspheres, and amorphous aluminosilicates were found to be suitable for producing a low-density thermal-insulating lime–shell limestone–cement composition. The particle size of the shell limestone powder was 5.67 × 10⁻⁶ m, with calcium carbonate (CaCO₃) and silica (SiO₂) contents of 71.0% and 22.5%, respectively. The shell limestone and microsphere proportions in the binder substantially affected thermal conductivity (0.090–0.113 W/(m·°C)), compressive strength (3.25–4.05 MPa), adhesion strength to the substrate (0.8–1.2 MPa), flexural tensile strength (2.0–2.5 MPa), and water absorption coefficient (0.3–0.5%). The optimum thermal-insulating dry-mix formulation contained, by mass: lime, 25–40%; shell limestone, 15–20%; glass microspheres, 15–20%; amorphous aluminosilicates, 5–10%; diatomite, 2–10%; and cement, 0.5–4.0%.

This article presents the results of a research study on the development and evaluation of a mineral modifying additive for concrete produced from mineral-processing tailings, shale waste from shungite production, and silica fume. Compositions of both the modifying additive and concretes based on it were developed. The properties of the mineral modifying additive were studied; mechanochemical activation was applied to increase and modify its activity, and its pozzolanic activity was determined. Depending on the component ratio, CaO absorption ranged from 7.9% to 94%. In the technology of high-strength and functional concretes, high-carbon slag with a fraction of 10-20 mm was used as a partial replacement for natural coarse aggregate. The introduction of 3-15% mineral modifying additive into B40 concrete increased the 28-day compressive strength by 0.19-16%. The greatest increase was observed for concrete containing 8% mineral modifying additive by cement mass. Because compressive strength is not directly correlated with freeze-thaw resistance and water impermeability, capillary suction tests were performed. This non-destructive durability indicator makes it possible to assess concrete permeability, characterize the pore structure, indirectly evaluate freeze-thaw resistance through water-absorption behavior, and estimate the potential resistance of concrete to repeated freezing and thawing. After 24 h, the maximum increase in capillary suction ranged from 4.13% to 5.17%. Direct freeze-thaw testing confirmed freeze-thaw resistance grade F400. Three main criteria were used to assign the freeze-thaw resistance grade: average mass loss not exceeding 2%, compliance with the compressive-strength ratio XminII >= 0.9 XminI, and absence of cracks, spalling, and edge scaling on the specimens.

Despite the large volumes of marbleized limestone processing waste (MLPW) generated by the stone industry, its utilization in the production of high-strength masonry materials remains limited, and systematic comparative studies of white and gray Portland cements in hyperpressed MLPW-based bricks are scarce. In this study, four mixture formulations containing MLPW (70–85 wt.%), white Portland cement (CEM I 52.5, M500) or gray Portland cement (CEM I 42.5, M450), and water were prepared at a constant water-to-cement ratio of 0.25. Specimens were manufactured by hyperpressing under compaction pressures of 28 and 41 MPa and cured for 7 days in a sealed moist environment. The formulations compacted at 28 MPa achieved compressive strengths corresponding to brick strength grades M350 and M400. Increasing the pressure to 41 MPa yielded grades M400–M550 with white cement; under identical conditions with gray cement, grades M400 and M450 were attained. Among the tested formulations, those containing 75–80 wt.% MLPW (20–16 wt.% cement) showed the most favorable combination of compressive strength and density. The mechanical performance correlated well with the microstructural features observed by scanning electron microscopy (SEM) and EDS analysis. The average density of all specimens exceeded 2100 kg/m³, classifying the materials as heavyweight concrete. The novelty of this work lies in the comparative evaluation of white and gray Portland cements in hyperpressed MLPW bricks and the establishment of relationships between compaction pressure, binder type, overall mixture composition, and resulting strength grades. The results demonstrate a promising route for converting high volumes of industrial marble waste into high-strength masonry units. However, further investigation of durability-related parameters, including water absorption, frost resistance and flexural strength, is required before the practical application of the developed materials can be fully evaluated.