Results of research of waste ash-and-slag mixture being a waste product of thermal power plants are presented. Effectiveness of its use as a mineral component of a complex organic-mineral additive is shown. Methodology of mathematical modeling and optimization of properties of concrete modified by complex organomineral additive allowing to reduce cement consumption by 20% without loss of concrete strength is presented.

Keywords: оrganomineral additives, industrial waste, mathematical modelling, cement saving

The article proposes new compositions of a fast-hardening concrete mixture using Portland cement, fine and coarse aggregates, basalt fiber, a complex modifying additive including acetone-formaldehyde resins and magnesium chloride (bischofite). The results of scientific and experimental studies are presented and the influence of the proposed additives on the formation of the structure, rheological and physico-mechanical properties of fast-hardening concrete is determined. Analysis of the test results showed that the proposed formulations, including a complex additive and basalt fiber, contributed to a decrease in the water-cement ratio, increased mobility of the mixture and increased strength of hardened concrete in the early and final hardening periods.

Keywords: concretes, oil and gas storage, modifying additives, fiber, mobility, setting time, strength

This article discusses strength testing of welded joints by pulling joint materials using an automated material testing system.

Keywords: YAG laser welding, packaging of photonic devices, laser processing of materials.