To obtain high-quality concrete constructions it is not enough to execute it only in concrete of high class. One of the effective ways to improve the reliability and durability of concrete is its reinforcing by various kinds of fibers. The article presents the researching results of the influence of brands of portland cement and disperse reinforcing by polyethylene terephthalate fibers (PET-fiber) on concrete durability. Standard compression tests of the cubical prototypes of fine-grained sand concrete made of two brands of portland cement-PC400 and PC500 with different percentage of PET-fibers have been conducted. The optimum content of PET-fibe, wherein there is a maximum increase of durability of fine-grained fiber-reinforced concrete, has been set.

The usage of the low-cost catalysts for methylene blue removal from wastewater was investigated. Heterogeneous Fenton-like process consists of the use of a hydrogen peroxide solution, and an iron-rich catalyst, red mud and black nickel mud were used for that purpose. The factors such as the catalyst dose and the hydrogen peroxide solution volume were monitored. The results of experiments showed that the degradation of methylene blue dye in Fenton-like oxidation process using selected catalysts can be described by a pseudo-second-order kinetic model. The highest dye removal efficiency (87.15 %) was achieved using the black nickel mud catalyst after 30 minutes of reaction.

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The article analyzes temperature fields over foam concrete samples reinforced by PET fibers. The samples are developed at the Votkinsk branch of Kalashnikov Izhevsk State Technical University. The effectiveness of reinforced PET fibers has already been proven, but so far, the effect of PET reinforcement on the thermophysical properties of foam concrete has not been well studied. In the laboratories of the Technical University in Zvolen, Slovakia (TUZVO), the heat transfer is analyzed using natural convection by heating reinforced foam concrete samples. The method of holographic interferometry is used, which allows to visualize temperature fields in real time. Temperature fields arising above the samples are displayed and recorded by a Mach-Zehnder interferometer using the «living boundary» method throughout the entire length of the interference fringes. A method for calculating the parameters of heat transfer by analogy with the heating of a flat plate has been proposed. Qualitative and quantitative analyzes of holographic interferograms of the temperature fields are carried out. The local heat transfer parameters are calculated: the heat transfer coefficient α and the heat conductivity coefficient λ. It has been established that the samples of foam concrete reinforced by PET fibers made in Russia have a higher heat resistance and better insulation than foreign analogues.