Many types of the corrosion of Portland cement stone immersed into inorganic liquid media are conditioned by chemical exchange reactions between the substances dissolved in them and cement hydration products. To prevent the corrosion formation in corrosive media it is necessary to form cement clinker hydration products that do not enter into ion exchange reactions in the solutions. The concrete structure defines the penetration rate of corrosive ions and that of the removal of corrosion products, in other words the behavior of corrosive processes. The investigations that were carried out showed that the presence of finely dispersed organogenic calcite (chalk) in the cement stone composition results in a change of the phase composition of the hydrates of new formations, i.e. it results in a decreased content of the free calcium hydroxide and the binding of aluminate phases to form stable hydration products. The use of this additive contributes also to the compaction of the microstructure of cement stone due to the occupation by additive grains of the vacancies in the gaps between the cement grains and due to an increased dispersion of hydration products for which calcite particles serve as crystallization centers. All these factors contribute to an increased corrosion resistance of the cement stone and the concrete exposed to the action of corrosive solutions.

MATEC Web of Conferences, open access proceedings in Materials science, Engineering and Chemistry

This research presents the results of studies on the physical and mechanical properties of the soil–polymer composites developed by the Scientific and Production Company “Special Polymer Technologies” SPT^® by injecting polyurethane material into clay soils to strengthen the foundations of erected structures. A novel method is proposed to determine the strain characteristics of these composites, embracing the preparation of model specimens in cylindrical containers with subsequent static and dynamic load testing. The results of static tests showed a significant increase in the strain modulus in comparison to that of the soil, resulting in soil stabilization due to a decrease in the initial content of moisture squeezed out of the modified soil. A coefficient of increase in the deformation modulus (K_E) is introduced to quantitatively assess the soil stabilization efficiency. An original technique is also proposed for assessing composite durability, and it is based on analyzing the mass loss after cyclic wetting and drying. The proposed soil stabilization approach promotes and improves digital construction technologies such as Building Information Modeling (BIM) by enabling the accurate simulation and prediction of the behavior of loaded soil in foundation systems. The introduced quantifiable metrics can be integrated into Digital Twin- or BIM-based project planning tools, contributing to sustainability, safety, and reliability in modern construction practices.

Complex industrial systems are still very dependent on the operator’s human errors. Many automated control systems have been developed for the needs of rail transport. The safety of train movement directly depends on some of them. In case of a malfunction during the operation of such systems, they pass into a safe state and most traffic safety tasks are transmitted to the operator or station operator. To obtain quantitative values ​​of the probability of timely execution of operations by the duty officer at the station, a functional-semantic network and a corresponding model are proposed. This work investigates the connection between the probability of timely execution of operations and the psychophysiological state of the duty officer in case of complex industrial systems problems on the railway transport.

A mechanism of the influence of the electric field of the negatively charged particle surface of hydrosilicate gel on the diffusion coefficient of calcium cations Са²⁺ has been described. The formula was derived for the dielectric water permittivity in the boundary layer. The dependences of the dielectric permittivity of water in boundary layers on the distances to the surface were given for different electrosurface potentials that characterize the calcium hydrosilicates CHS of a different basicity. The values of the diffusion coefficients of calcium ions Са²⁺ were calculated for the concrete with different water-to-cement ratio.

The objective of this study is to develop a physical model of a prestressed reinforced concrete railway sleeper, to construct a corresponding finite-element model, and to compare the experimental and numerical results. During operation, many of them sustain damage due to cracks. The article deals with the crack resistance of sleepers, specifically the impact of anchoring on reinforcement. Physical models of concrete sleepers were designed and fabricated; they included specimens with non-anchored or anchored reinforcement. Their finite-element models were constructed, and both computational and full-scale experiments were carried out; they also included their loading to failure. It is found that the anchoring of reinforcement does not improve the crack resistance or strength of the models, and even leads to a slight reduction in their properties. It has therefore been found that the anchoring of reinforcement does not improve the resistance of sleepers up to the formation of transverse cracks in the under-rail and mid-section areas; however, it can be considered as a technological measure, as well as a measure for protecting the ends of rebars from contact with the external environment to prevent leakage currents from flowing through them. The results obtained make it possible to design sleepers with anchored reinforcement to achieve the required crack resistance.