The study presents the treatment of soil with chitosan and xanthan gum, examines the influence of the pH of base solutions on the solubility and activity of these biopolymers, and investigates the changes in soil properties resulting from their application. The first stage of the study is devoted to the peculiarities of preparing soil reinforcement with biopolymers and their mixing process. The obtained samples were analyzed for their texture, which allowed identifying the optimal conditions for maximum solubility. The second stage of the study is devoted to evaluating the modified soil's behavior under wetting conditions. The moisture level of the soil directly affects its physical and mechanical properties. Understanding these changes makes it possible to predict the behavior of the soil under different service conditions. The study considered 10 soil samples prepared with base solutions of different acidity (pH 4, pH 7, pH 9), among which one sample serves as a control sample without modification with biopolymers. This makes it possible to evaluate the effect of modification on soil properties and to identify optimal conditions for its use. The analysis showed that the solutions' moisture level and acidity significantly affect the samples' structural characteristics. At the same time modified soils show improved performance compared to the control sample, the sample reinforced with chitosan increased density by 16 %. These data are important for the development of effective solutions in geotechnical and construction engineering.

This study examines the behavior of frozen soils at a construction site in Astana, Kazakhstan. Field static load tests (SLT) and dynamic load tests (DLT), were conducted using driven piles embedded in alluvial Quaternary deposits overlying a 2.5 m permafrost layer. SLT results reveal settlements below 20 mm at a maximum load of 1400 kN, supporting a design capacity of 1167 kN after applying a safety factor of 1.2. Notably, creep behavior was observed in the upper soil layers, and lateral displacement patterns indicate complex interactions within the frozen soil. These findings highlight the need for further research into soil creep and lateral deformations in frozen environments.

The research investigates the transformative potential of fly ash, an industrial byproduct, in enhancing concrete compressive strength and addressing environmental concerns associated with its disposal. The study employs a rich dataset from Mendeley Data, comprising 471 data points, to comprehensively explore the impact of fly ash on concrete strength at different ages. The analysis involves determining optimal compositions with fly ash, evaluating the fraction of cement replacement, and analyzing the generalized effect on compressive strength through graphical representation. Results reveal an inverse relationship between fly ash content and compressive strength, with nuanced patterns emerging at different curing ages. Despite the negative correlation, opportunities exist to optimize concrete formulations for specific strength requirements by judiciously incorporating fly ash. The weighted sum analysis identifies a composition with 33.6% replacement of binder by fly ash as optimal in the long term, showcasing the potential of this waste product as a valuable resource in sustainable concrete engineering.

This study evaluates regional variability in seasonal frost-penetration depth beneath the existing pavement structure and the frost susceptibility of pavement subgrade soils under the climatic conditions of Kazakhstan. Normative frost-depth values were compared with values calculated using a freezing index-based expression for eight cities representing northern, southern, western, and eastern Kazakhstan. Relative differences between the two estimates ranged from 6.6% to 37.7% (mean absolute percentage difference: 23.2%). The formula-based estimate exceeded the normative value in seven cities, whereas it was 37.7% lower in Shymkent, demonstrating that a uniform calculation approach may introduce substantial regional bias. Complementary laboratory tests performed in accordance with GOST 28622 on seven soil specimens produced final vertical heave values of 7.16–18.91 mm. Lean clay, clayey sand, and silty sand generally showed greater heave than the tested poorly graded sand soils, although one clayey-sand specimen exhibited a markedly lower response, highlighting within-class variability and the need to account for moisture state and fines characteristics. The laboratory measurements provide a controlled assessment of relative frost susceptibility; they are not a direct validation of regional frost-depth estimates. The findings support region-specific calibration of frost-depth calculations and the combined use of drainage, non-frost-susceptible replacement layers, thermal insulation, and geosynthetic reinforcement where local hydrogeological and traffic conditions justify these measures.

In modern low-rise housing construction, metal tiles, rolled roofing, various types of wooden roofing, metal roofing, precast reinforced concrete slabs, wavy asbestos cement sheets, reinforced concrete rafters are used for roofs and roofs. The production of many of these types of roofs has a limited industrial base, requires significant consumption of materials and labor intensity of construction work, or involves significant consumption of wood, and their production volumes do not meet the demand of modern construction. An alternative solution is the production of one of the slab materials – cement-chipboard (CB). The purpose of the article is to develop a roof structure using cement-chipboard, a comprehensive study of the stress-strain state of this structure, and the development of an approximate method for calculating the strength and deformability of a СB on an elastic base.