Keyword: «durability»

This study investigates the effect of polymethylsilsesquioxane aerogel on the water absorption of cement composites. The relevance of this research is driven by the need to enhance the durability of concrete structures exposed to aggressive water saturation and cyclic temperature variations. Concrete cube specimens with a 100 mm edge were fabricated using a constant mixed design, with aerogel added at 0%, 0.2%, 0.375%, and 0.475% by cement mass. Water absorption tests were performed in accordance with GOST 12730.3-2020. The results demonstrate that aerogel incorporation proportionally reduces water absorption. At the maximum dosage (0.475%), water absorption decreased from 5.70% to 3.10%, representing an approximate twofold reduction. These findings confirm the potential of superhydrophobic nanoporous aerogels as effective bulk modifiers for developing a water-repellent cement matrix without significantly increasing the structural mass.

The article describes technogenic waste in the context of its widespread use in construction. It provides a brief review of scientific studies that confirms the mechanisms of action of additives in concrete mixtures, describes the environmental impact on the environment, and formulates recommendations for further research.

The article presents the results of research on the use of fiber concrete as a material for the production of reinforced concrete sleepers. The advantages of dispersed reinforcement compared to traditional rod reinforcement are substantiated, and the regulatory requirements for concrete for underrail bases according to Russian standards are presented. The analysis of the composition of the fiber concrete mixture, the technology of molding, and the strength indicators is conducted. Recommendations are given for optimizing the dosage of steel fiber and the modes of heat and moisture treatment. It has been shown that the use of fiber concrete can increase the crack resistance, durability, and fatigue strength of sleepers, as well as reduce the labor intensity of production.

The paper discusses the mechanisms of the alkaline-silica reaction in concrete and its impact on the reduction of the material's physical and mechanical properties. Domestic and foreign regulatory documents governing the testing of the reactive capacity of coarse aggregate are studied. The paper presents the methodology of experimental studies aimed at assessing the degradation of the strength characteristics of high-strength concrete by determining the reduction factors.