Technobius

Comprehensive overview of the macroscopic thermo-hydro-mechanical behavior of saturated cohesive soils

2025-03-02T00:36:51+05:00

Understanding the effects of temperature on the hydro-mechanical behavior of geomaterials (i.e., soil and rock) has gained significance over the past three decades. This is due to new applications in which these materials are subjected to non-isothermal conditions. Examples of such applications include geothermal systems, nuclear waste disposal, and energy geo-structures. The analysis and design of such applications requires a thorough understanding of the macroscopic thermo-hydro-mechanical (THM) behavior of the geomaterials. Although various aspects of this behavior have been documented in the literature, a comprehensive overview of such behavior is lacking. This article presents such an overview of the macroscopically observed THM behavior of saturated cohesive soils.

Rehabilitation of lengthy sewer pipelines by polymer-composite CIPP

2025-03-02T21:38:27+05:00

This study examines the feasibility of Cured-in-Place Pipe (CIPP) technology for trenchless rehabilitation of aging sewer pipelines, addressing the severe deterioration of Karaganda’s sewer networks. A 3 km section was inspected using CCTV, ultrasonic, and shock-pulse methods to assess pipeline conditions, revealing structural defects with depreciation levels reaching 70-100%. The CIPP method was successfully applied to restore the integrity of 2.6 km pipelines while minimizing excavation, stabilizing the average flow rates and velocity of 0.8-1.2 m pipelines at 710 liter/s and 1.2 m/s, respectively. Hydraulic analysis confirmed that rehabilitated pipelines maintained sufficient flow velocity for self-cleaning and increased capacity, reducing blockage risks. The findings demonstrate that CIPP is a sustainable alternative to pipeline replacement, offering a viable solution for long-length sewer rehabilitation and supporting strategic urban infrastructure renewal.

Field studies of frozen soils composed of alluvial Quaternary deposits

2025-03-02T21:38:29+05:00

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.

Prediction of compressive strength and density of aerated ash concrete

2025-03-06T20:12:54+05:00

The article presents the results of studies on forecasting the compressive strength and density of aerated ash concrete. A theoretical review was conducted on the variability of strength and density of cellular concretes when selecting their compositions. A series of experiments was conducted to study the dynamics of changes in the compressive strength and density of non-autoclaved gas-ash concrete during the initial stages of hardening under natural conditions and after thermal treatment to select a composition of the specified quality. It was revealed that it is possible to control both the strength and the density at the early stages of hardening to forecast these parameters at the design age of 28 days. It was established that the compressive strength of aerated ash concrete samples hardening under natural conditions increased by an average of 42.62% at the design age compared to the strength at 7 days, while the density decreased on average by 19.19%. For aerated ash concrete samples that underwent thermal treatment (steaming), the increase in strength averaged 34.67%, and the decrease in density was 11.07%. The obtained results are of practical value for scientists and engineers engaged in the development of cellular concrete compositions.

Effect of glass waste on ceramics and concrete production

2025-03-18T18:25:41+05:00

The article is devoted to the study of using glass waste for ceramics and concretes production. The results of the spectral analysis of glass composition are presented, and phase changes and their impact on the microstructure and strength properties of ceramics and concrete are studied. Scanning electron microscopy and energy dispersive X-ray spectroscopy of the final material are discussed. As a result, it was revealed that after 28 days, concrete with added glass powder delayed the strength rise, but by day 112, the strength had considerably grown to 76.36 MPa. This results from pozzolanic reactions, where calcium hydroxide and glass combine to generate more hydration products that boost strength. Glass-based ceramic shows 13.20 MPa compressive strength, which satisfies construction material criteria, and was achieved by adding glass waste at a level of 10% of the clay mass. In addition to lowering the demand for natural mineral resources, the use of glass in ceramic blends promotes sustainable development and lessens the environmental load. Both the ceramic and concrete samples had a high content of SiO₂ and Al₂O₃ oxides. These are the main components that provide the material with high mechanical strength and chemical resistance. In the Spectral analysis of glass, in all the graphs, we see a high tendency for silicon dioxide (silica). This is explained by the fact that SiO₂ belongs to the group of glass-forming oxides, i.e., it is prone to the formation of supercooled melt-glass.

Physicochemical properties of silica fume and fly ash from Tau-Ken Temir LLP and Pavlodar CHP for potential use in self-compacting concrete

2025-03-18T18:24:44+05:00

This article presents the results of a study on the structural and chemical properties of silica fume and fly ash from local plants, focusing on their potential as mineral additives in self-compacting concrete. Scanning electron microscopy (SEM) and X-ray fluorescence (XRF) analysis were used to investigate particle morphology, microstructure, and elemental composition. Silica fume was characterized by a high SiO₂ content (>75%), spherical particle morphology, and a smooth surface, which promotes the formation of a dense cement matrix. Fly ash exhibited a complex chemical composition dominated by SiO₂ and Al₂O₃ oxides, with spherical particles and surface roughness enhancing adhesion to the cement paste. The results demonstrated that the combined use of silica fume and fly ash has the potential to improve concrete workability, increase strength, reduce the water-cement ratio, and enhance durability due to microstructure densification. Partial cement replacement with these additives may not only optimize concrete performance but also reduce the environmental footprint of cement production. The findings highlight the efficiency of silica fume and fly ash as pozzolanic components for developing high-performance and sustainable self-compacting concrete.