durability

The increasing accumulation of waste tires has encouraged the development of sustainable strategies for incorporating rubber into cement-based materials. In addition to aggregate replacement, fine rubber crumb can function as a modifier of the cement matrix, influencing hydration processes and microstructure development. This review summarizes current research on the effects of fine rubber particles on hydration kinetics, interfacial transition zone formation, mechanical performance, and durability.

The article provides review of modern cement repair mortars for restoring the surface of reinforced concrete structures and analyzes their composition, properties, application technologies and environmental impact. The features of the composition of repair mortars and the role of mineral additives, hardening accelerators and nanomodifiers in the formation of the microstructure of cement mortar are shown. The possibility of using composite cements and alkali cements to obtain repair mortars with increased durability is demonstrated.

The article presents the results of research on the crack resistance of high-strength concretes modified with fly ash and basalt fiber. It is shown that fly ash, acting as a pozzolanic additive, reacts with portlandite and forms additional low-basic calcium silicate hydrates (C-S-H), thereby densifying the microstructure of the cement paste and reducing the development of microcracks. Basalt fiber performs the function of dispersed reinforcement and increases the strength and energy characteristics of concrete.

The technological features of obtaining hydrophobized polymer coatings based on unsaturated polyester resins are considered. The feasibility of investigating the hydrophobicity of the studied materials is substantiated. It has been established that moisture exposure is one of the key factors in the degradation of the polymer matrix, leading to a reduction in mechanical performance and protective properties of the coatings. The relationship between the composition of the system, surface morphology, and wetting characteristics of polyester composites is analyzed.

This review analyzes key factors contributing to damage in reinforced concrete (RC) structures, including reinforcement corrosion, chemical attacks, cyclic and long-term mechanical loads, and extreme temperature effects. The study highlights crack formation as a primary damage mechanism, leading to structural degradation. Advanced computational modeling techniques, such as finite element analysis, offer valuable insights into crack propagation and corrosion processes but require further refinement.

This study reviews the current state of research and limitations on the fatigue strength of web-flange connections in steel runway beams for overhead cranes. It evaluates key factors influencing fatigue strength, including stress-strain behavior, notch classifications, and various web-flange configurations (welded, rolled, combined). The research stresses the need for accurate fatigue life assessments, particularly for both new and older structures built with simplified standards.

Для визначення показників довговічності систем зі структурним резервуванням запропоновано метод, який ґрунтується на застосуванні багатовимірних ациклічних марковських моделей. На основі запропонованого методу для дубльованої системи із паралельним резервуванням визначено гамма-процентний ресурс, інтенсивність відмов та ймовірність розподілу за відмовами.

This paper describes the synthesis of geopolymer materials using thermally modified clay rocks of Georgia and metallurgical granulated blast-furnace slag; as well as the study of their physical and mechanical properties, durability, and corrosion resistance in aggressive solutions.The methods of chemical, X-ray phase, differential thermal analysis and SEM were used.

Among the several kinds of thermoplastic adhesives, structured and non-structured polyvinyl acetate (PVA) adhesives have a rather wide application and are used currently for forming adhesive joints from different wood species, especially oakwood. To ensure proper conditions of oakwood adhesive joints use, it is important to have fast and accurate methods of predicting their strength and durability. The strength changes of the oakwood adhesive joints bonded with structured and non-structured PVA adhesives have been investigated by conducting long-term experiments.