The article presents results of self-compacting concrete with microsilica and grinded concrete crush additive study. The work presents concrete mix designes and mechanical tests results.Found that with the use of complex additive it is possible to obtain concrete of class B80 with a strength of at least 60 MPa after 7 days of hardening under normal conditions. High frost resistance of such concrete is noted. Concluded the possibility of complex additive application and potential advantages of its usage in self-compacting concrete.

Keywords: self-compacting concrete, silica, active mineral additives, concrete crushing screening, concrete, concrete scrap, finely ground filler, secondary filler, construction waste, determination of mechanical characteristics of concrete, high-strength concrete

The analysis of the frequency-controlled drive currently used on the technological equipment of the Volgogradneftemash enterprise is presented. Taking into account the peculiarities of the pumping and ventilation equipment installed at the enterprise, the principles of regulation are determined and the influence of a frequency-controlled drive on the quality of electrical energy is evaluated. The negative influence of the frequency-controlled drive of ventilation and pumping equipment on individual indicators of electricity quality was noted. In order to reduce this influence, an energy-saving device has been proposed for installation. The issues of the possibility of using an energy-saving device at the facility are considered, as well as an analysis of its efficiency during operation from the point of view of improving the quality of electricity in the internal power supply system of the Volgogradneftemash open Joint stock company is carried out. The use of the device is an effective solution, since it leads to high energy efficiency of technological equipment by reducing current surge, suppression of higher harmonics and electromechanical interference.

Keywords: electric drive, ventilation system, frequency-controlled drive, quality of electrical energy, energy saving device

The article is devoted to the problems of the use of building waste in the demolition of houses, as well as substandard products at housing enterprises. The issues of concrete scrap processing, methods of its crushing to obtain materials that can be reused to create reinforced concrete products and structures are considered. Concrete scrap has been investigated for compliance with requirements for large aggregate for construction works. Compositions based on conventional coarse aggregate, concrete scrap and conventional fine aggregate have been developed. For the compositions, the technological characteristics of the concrete mixture are determined, as well as the physical and mechanical characteristics of the concrete at 28 days of age. The use of such compositions for the production of reinforced concrete structures is justified.

Keywords: concrete scrap, secondary crushed stone, concrete, characteristics of concrete scrap, recycling, construction waste, large aggregate from concrete scrap, application of concrete scrap

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