This paper presents studies on the possibility of utilization of technogenic waste from the metallurgical industry by the method of complex processing in order to reduce the anthropogenic load on the environment of the region with the example of the zinc silicate-magnetite-carbon system. The selected sample of clinker dump from welting was subjected to chemical and scanning electron microscopic analyses and thermodynamic modeling. Thermodynamic studies were carried out in the temperature range 1600–2200 K and pressure p = 0.1 MPa, modeling the process of electric melting of clinker from welting in an arc furnace using the software application Astra 4 developed at the Bauman Moscow State Technical University (Moscow, Russian Federation). As a result of the thermodynamic modeling, the optimal temperature range was established, which was 1800–1900 K. Thermodynamic studies established that it is possible to drive away zinc from the system under study by 99–100% in the entire temperature range under study. The maximum degree of silicon extraction (αSi) in the alloy is up to 69.44% at T = 1900 K, and the degree of iron extraction (αFe) in the alloy is up to 99.996%. In particular, it was determined and proved that clinker waste from welting can act as a secondary technogenic raw material when it is processed as a mono mixture to produce iron silicides with a silicon content of 18 to 28%.

A new methodology to obtain metallic functional materials with predefined sets of strength properties has been developed. It has been shown that in order to accurately estimate set of material properties at the macro‐level, information from the micro‐level needs to be taken into account. As a result a two‐level estimation model, based on the theory of fuzzy sets, has been proposed. To demonstrate the developed methodology, a reinforcing steel has been analysed. Using microstructural information, derived from an available set of experimentally obtained digital images of material microsections under different heat treatment conditions, macroscopic strength properties of reinforcing steel have been determined.

No abstract

No abstract

In the article the questions of application of the mining waste: dropout of quartzite sandstone crushing as filler in the fibre concrete production were considered. Composite binders based on cement and dropout of quartzite sandstone crushing were also developed. The effectiveness of composite binders’ usage consisting in improving the physical and mechanical characteristics and reduction of their prime cost compared to the cement with a slight increase in the complexity of their production was proved. The compositions of concrete dispersed reinforced with steel wave fiber and without it were developed. The efficiency of the use of dispersed reinforcement of fine-grained concrete is proved, which consists in improving the performance characteristics.

No abstract

The necessary fiber content in the first place is determined by the requirements of bending strength and resistance to dynamic loads. The fiber content depends on the composition and consistency of concrete, fiber properties and mixing techniques. The most widespread types of fibers, their advantages and disadvantages, possible areas of their application are considered. Fibers whose modulus of elasticity is greater than the modulus of elasticity of a concrete matrix, such as steel fibers or glass fibers, increase the workload on the cracks.

fine-grained fiber concrete used in 3D printing is significantly different from conventional heavy concrete, which is determined by the increased consumption of cement, low water-cement ratio and the absence of large aggregates. The largest grain size of fine aggregate is selected taking into account the thickness of the section, the frequency and type of reinforcement, as well as the method of concrete placement. Despite the fact that the tensile strength of concrete on fine sand is more than 1.5 times higher than the strength of concrete on coarse sand, while there is a decrease in compressive strength. Due to the peculiarities of the technology of concrete manufacturing for layering, the use of coarse sands is impractical, and therefore it was decided to use quartz sand with a particle size module of 1.12 as a filler.