The research on determining rational parameters of heat treatment of a concrete mixture based on hollow aluminosilicate microspheres has defined the features of the intensifying action on the structural concrete mixture by low-pressure steam with optimum heat and mass transfer. Optimum values of temperature, humidity and speed of the medium have been identified. The obtained heat treatment parameters are subject to general regularities of structures for the formation of hydraulic bindings and are in accordance with production conditions, thus providing possibilities for their adaptation into production. The mechanisms for determining the strength of concrete stone according to the structural and thermal effectiveness of the active medium have been defined. Thanks to the strength-building mechanisms obtained, it is possible to reduce the thermal destruction capacity of the system while reducing the process heat consumption. It is confirmed that the main direction in reducing the destructive capacity is determined by the mass flow of moisture, which has the greatest heat capacity and the least thermal conductivity at the initial stages. The invention relates to periods of temperature rise and isothermal heating without impairing the mechanical properties of concrete. It is shown that the real duration excludes high-temperature destruction processes, thereby increasing the mechanical strength of concrete and reducing the overall energy consumption. Thus, there is a reason to argue that it is possible to produce strong and light concrete products under accelerated structure formation and new technologies for heat treatment of concrete based on lightweight fillers with reduced heat consumption.

This study investigates the microstructural transition and densification behavior of xanthan gum–modified soil using quantitative scanning electron microscopy (SEM) analysis. Soil specimens were prepared with 0%, 3%, 6%, and 9% xanthan gum content. SEM images were processed using image analysis techniques to determine the solid area fraction and characteristic particle size parameters. A densification index was introduced to quantify the ratio between solid and pore phases within the observed microstructure. The results reveal a non-monotonic structural evolution with increasing polymer content. The solid area fraction reached its maximum at 3%, indicating the compact particle arrangement. At 6%, a pronounced decrease in densification was observed, suggesting disruption of particle packing due to non-uniform polymer distribution. At 9%, partial recovery of structural continuity occurred, accompanied by evidence of polymer agglomeration and spatial heterogeneity. Based on quantitative metrics and microstructural observations, three structural stages were identified: discrete particle stage, bridged stage, and matrix-dominated stage. The findings demonstrate that xanthan gum dosage significantly influences soil microstructure in a nonlinear manner. This SEM-based approach provides a systematic framework for identifying microstructural transitions in biopolymer-modified soils.

This article presents the results of a computational parametric study, a global sensitivity analysis, multi-objective optimization, and a technical and economic evaluation of the parameters of phase-change materials (PCMs) incorporated into the building envelope of an office building in a sharply continental climate (using Astana, Kazakhstan, as an example). The study was conducted using simulation modeling, incorporating dynamic thermal calculations in the EnergyPlus software package and the NSGA-II genetic algorithm. The CondFD algorithm was used, for which results of independent verification and experimental validation conducted by other researchers have previously been published. This study used this validated implementation without conducting additional experimental verification of the structure under consideration. Based on the results of a parametric analysis (1232 calculations) and an optimization run (≈25,000 calculations), the range of quasi-optimal phase transition temperatures for the PCM was determined to be 23–25 °C. For further analysis and a technical–economic evaluation, a value of 24 °C was selected as the recommended compromise solution, with a PCM layer thickness of 16 mm and a distance of 15 mm from the inner surface of the wall. This compromise solution reduces annual specific energy consumption for heating and cooling by 22% and hours of thermal discomfort by 42% compared to a reference concrete wall without PCM. A technical and economic assessment, based on post-processing of the simulation results using current electricity rates and market data on the cost of PCM, shows a simple payback period ranging from 3.8 to 38 years, depending on the assumed cost of the encapsulated PCM layer. The results are limited to the specific case considered (south-facing orientation, standalone office module, and continuous ventilation) and are intended for subsequent experimental verification. The information in this article can be used by architects and engineers in the early stages of designing energy-efficient office buildings in regions with a sharply continental climate.

This study investigates the multi-objective optimization of phase change materials (PCM) in building envelopes for office buildings under sharply continental climate conditions. The study employed simulation modeling with dynamic solutions in EnergyPlus (CondFD algorithm) and the NSGA-II genetic algorithm. During the computational experiments, the optimal values for the PCM melting temperature (24–25°C), layer thickness (15–21 mm), and its position relative to the inner wall surface (10–20 mm) were determined. The results show that a properly selected PCM can reduce annual energy consumption by up to 22% and hours of thermal discomfort by up to 42% compared to a traditional concrete wall. The obtained calculation data can be used by architects and engineers when designing energy-efficient office buildings in regions with a sharply continental climate. As such, these results provide design-oriented practical guidance for integrating PCM into building envelope design to support eidence-based decision-making at early stages of any projects.

This study presents the control test process to assess the bearing capacity, crack resistance, and crack opening width of the volume block ceiling slabs and the floor slab of the inter-block corridor. These parameters play an important role in ensuring the reliability and durability of buildings, especially when volumetric blocks are used in construction. The study's first phase focuses on the methodology of load-carrying capacity testing of ceiling slabs. The study's second phase focuses on the materials' crack resistance. The analysis of cracks in the material structure is a key aspect since cracks can lead to deterioration of its mechanical properties and reduced durability. The third stage of the study focuses on the crack opening width. This parameter is important in determining the criticality of cracks and their effect on structural integrity. The fourth stage of the study covers the analysis of the floor slabs of the interlocking corridor. Considering the peculiarities of loads and operating conditions in this context, tests analyzing the bearing capacity and stability of the slabs are carried out. The crack opening width reached 0.9 mm and the vertical deflections exceeded 50 mm, the deflection in the inter-block corridor floor slab before failure was about 11 mm. The test results indicate its sufficient strength, stiffness, and crack resistance. The study provides a deeper understanding of the properties and characteristics of materials used in construction and optimizes their use to improve the strength and durability of buildings.

In this study results of the active medium parameters influence formed by hot air on the thermal heating process of weakly reactive coal from the formation «Maikubensk 3B» for the extraction of additional heat are represented. In the course of the research the regularities of the hygroscopic moisture and volatile combustible substances release for the obtaining additional heat have been determined. Optimal temperature ranges of the stage heating taking into account thermal destruction of coal in the temperature range from 20 C to 600 C, the main steps of the insulated heating process, the moisture content gradient propagation lines and dependence of the heat transfer and mass transfer coefficients on the temperature and the humidity during the thermal heating process in the horizontal coal heating reactor. The results show that it is possible to release volatile combustible gases with a gradual increase of temperatures in the obtained mode. The heating mode comprises a pre-heating stage with hydroscopic moisture release, in the temperature range from 20 C to 105 C, the stage of isothermal heating in the temperature range from 105 C to 400 C and the phase of flame-free combustion in the temperature range from 400 C to 600 C with the temperature rise above the set value. Process simulation was carried out in the Comsol Multiphisics software environment for the weakly reactive coal real-world heating conditions. Keywords: coal heating, weakly reactive coal, isothermal heating, step-by-step heating, Lagrange method, non-liner equation, non-stationary process.