Medetbek Kambarov

This article presents a methodology for the comprehensive assessment of facade systems that combines LCA and LCC approaches and is adapted to the climatic and economic conditions of Kazakhstan. A MATLAB-based software implementation automates calculations based on ISO and EN standards, integrating life cycle matrix models with discounted cash flows and Monte Carlo simulation to account for uncertainties. The effectiveness of the methodology is demonstrated using a sample case: a comparison of four types of facades (SFTC, a ventilated facade with ceramic granite, PIR/PUR sandwich panels, and a facade with integrated photovoltaic modules) over a 50-year period. The input data for this example were taken from publicly available secondary sources and are not tied to a specific project. Therefore, the resulting values illustrate the structure of the model’s input data and the order of magnitude, but do not constitute a project-specific assessment. Even from this example, it is clear that the difference in life-cycle costs between the systems is significantly smaller than the difference in capital costs. The rate of growth in energy tariffs and the discount rate have the strongest influence on the LCC variance, while the price of materials has a weaker influence. After filling in the input matrices with data from a specific project, the methodology can be used to compare different options for building envelopes in various climatic regions of Kazakhstan.

Given the high energy intensity of the cement grinding process, the development of new and effective intensifiers is a pressing issue. The aim of this work is to develop grinding intensifiers from secondary raw materials produced during carpet manufacturing and gas processing wastes, and to study their effect on the structure and strength of modified cement stone. Methods of physicochemical analysis of raw materials and the obtained grinding intensifier, as well as standard methods for testing cement stone were used in the work. The possibility of obtaining an effective intensifier through the interaction of HYPAN (Hydrolyzed polyacrylonitrile) and diethanolamine was established. The optimal dosage of the grinding intensifier was determined to be 0.1%, which allows increasing the grade strength of modified cement stone by 31.2% and reducing the water consumption by 11%, which is explained by hydration due to the additional effect of reducing the electrokinetic potential between cement particles and increasing the fineness of cement particle grinding. Physicochemical analysis methods established that there is practically no free water in the modified cement stone sample and that the formation of the structure in the cement stone was achieved to a much greater extent. It has been established that, over time, the amount of C-S-H hydration products and calcium sulfoaluminate in the cement matrix of modified cement stone increases, which leads to an increase in the strength of the cement.

This article presents the results of a study exploring the potential use of gas processing waste as a raw material for synthesizing cement grinding intensifiers. Effective raw materials for synthesizing grinding intensifiers were identified: methyldiethanolamine (a gas processing waste) and hydrolyzed polyacrylonitrile (HIPAN) obtained from recycled nitrofiber. The use of alkanolamines as a raw material for synthesizing grinding intensifiers was substantiated. Physicochemical methods demonstrated the effectiveness of the methyldiethanolamine purification method. Optimal conditions for synthesizing grinding intensifiers were determined. Physicochemical analysis of the resulting grinding intensifiers revealed that all compositions exhibit a very strong C=O (amide) peak at 3300 cm⁻¹, a broad N-H elongation peak at 1236 cm⁻¹, and a strong C-N (amide III) elongation, which together confirm the clear presence of the amide group (-CONH-) required for grinding intensifiers. It was determined that the cumulative distribution curve of the product obtained with the addition of 0.25% of the synthesized grinding intensifiers G+M and G+T shifts toward finer grinding due to the unique combination of active components (alkanolamines, HIPAN), which allows them to act synergistically. HIPAN provides increased efficiency due to its high basicity, which reduces the electrostatic attraction between particles, leading to finer grinding and increased productivity.

This paper presents data on the synthesis of cement grinding intensifiers produced from oil and gas processing wastes, namely secondary alkanolamines. The results of physicochemical characterization of the raw materials are reported, including the optimal purification conditions for the wastes and the synthesis parameters of the grinding intensifiers, as well as the physicochemical properties of the obtained products. It was found that the optimal conditions for producing the grinding intensifier involve conducting the reaction at 45°C for 6 hours with a 1:9 component ratio. The effects of the synthesized intensifiers on the cement clinker grinding process were investigated, including their influence on particle size distribution and the mineralogical composition of modified cements. The particles of the modified cement were shown to exhibit a predominantly spherical morphology; the maximum laser diffraction value reached 13.5%, the intensity was 88%, and the particle size was mainly around 2 μm (more than 53.5%), while the fraction of particles within the 100-200 μm range was 4.87%. X-ray diffraction and differential thermal analysis revealed that hydration of the modified cement is accompanied by a slight decrease in the diffraction intensity of calcium silicate phases (C2S and C3S), whereas an increase in the diffraction intensity of calcium hydroxide (Ca(OH)2) was observed. This indicates the formation of calcium hydroxide and calcium silicate hydrate (C-S-H) during cement hydration. The diffraction peaks of these phases were detected within the ranges of 30-33° 2θ and 40-45° 2θ. In addition, the presence of aluminate (C3A) and ferrite (C4AF) phases within 40-45° 2θ corresponds to calcium carbonate (CaCO3) observed in low-intensity regions between 29.4° 2θ and 48.5° 2θ, which is associated with CO2 absorption from the atmosphere. These changes reflect phase transformations during hydration and the formation of phases that are critical for strength development. The optimal dosage of the grinding intensifier in the cement composition was determined to be 0.02 wt.% (based on dry residue).

The article presents the second stage of the investigate the effect of the modified additive on the strength characteristics of foam concrete. This work describes a method for manufacturing foam concrete samples, selects a modifying additive composition with different percentages of components, and analyzes their strength characteristics. The purpose of introducing plasticizing additives (post-alcohol bard) in foam concrete D600 to reduce water consumption and the expected increase in strength. To evaluate the changes in strength, samples were made and tested in compression at the age of 3, 7, 14, and 28 days of normal moisture curing. According to research results, the use of such additives can significantly reduce formwork removal times, increase the load-bearing capacity of structures, and expand the scope of application of foam concrete—even to structural and thermal insulation products. Additives improve not only strength but also structural uniformity, reducing the number of macropores and increasing the density of the material.

A theoretical study of the porosity influence on external building enclosures was conducted using ANSYS and Blender software packages. A foam concrete block with porosity up to 15% was investigated as an example of an external enclosure design. Pore content was analyzed from 1.5% to 15%. The percentage analysis of pores revealed that the thermal flow value shows a significant difference at 15% porosity, reaching up to 11.3 W/m², while porosity up to 10% indicates 12.2 W/m². Furthermore, with a difference of 1.31 times, the thermal flow value reaches 15 W/m² at 1.5% porosity. Additionally, the increase in porosity positively affects the effective thermal conductivity of the foam concrete structure and its thermal resistance. The obtained research results can be used to eliminate costly experiments and provide an accurate assessment of the thermal conductivity coefficient for external enclosures made of foam concrete blocks, taking porosity into account during residential building design

This paper reports a study of the frequencies and vibration modes of a vertical steel tank with a variable wall thickness in the ANSYS software suite using a finite-element model of vibrations of a tank with a volume of 3000 m³ for oil and petroleum products, hardened by a prestressed winding. The simulation was carried out for two variants of fixing the upper edge of the tank wall, which correspond to cases of absence or presence of tank coating. The estimation cases for the coefficients of the tension force of the wire relative to its tensile strength were investigated: at k₁=0.2; k₂=0.4; k₃=0.6 and k₄=0.8. Variation studies were carried out both taking into account the additional loads caused by the action of hydrostatic pressure from the maximum and half poured oil into the tank, and without oil. The magnitude of changes in the vibration frequencies of the tank wall without the influence of the coating varies within 12–27 % and when taking into account the influence of tank coating, 21–62 %, depending on the degree of filling of the tank. The revealed pattern relates to the fact that a decrease in the tension force of the filament in the winding leads to an increase in the frequency of oscillations. Thus, pre-stress can be applied to regulate the oscillation frequency of the tank wall. By decreasing which in the winding, it is possible to increase the natural frequencies of the wall and to lower the frequencies through an increase in the prestress. The research results can be used in the future as anti-seismic measures in the design and construction of steel vertical cylindrical tanks, as well as to improve the strength characteristics of existing cylindrical structures

Shrinkage has a great influence on the operation of the heat accumulator design, therefore, when developing structures with heat storage materials, it becomes necessary to determine the pressure in a non-expanding (closed) storage structure from the compressibility coefficient of the material, which can be considered an operational characteristic of the material. The article presents data on shrinkage (and expansion) of the investigated heat-storage materials and a method for estimating the pressure that can develop in sealed battery structures completely filled with heat-storage materials in a crystalline state. It has been determined that, for the normal operation of structures with heat storage material, it is necessary either to create conditions in it that allow avoiding an increase in pressure, or when filling the structures of the accumulator of heat storage material, take into account the shrinkage of the material, or use heat storage material with melting temperatures lower than is required when working at atmospheric pressure. pressure.

Development of the engineering procedure for the thermotechnical calculation of a building envelope with air chambers and a heat­reflecting coating