The active use in the production of building materials of waste after the renovation of housing is a relevant and promising direction. the load on logistics for the supply of inert materials is reduced, landfills and waste storage sites are being destroyed, and the cost of building materials from recycled materials is being reduced. The use of recycled clay bricks allows to solve the problem of solid waste disposal, but also to reduce the environmental damage caused to the environment by mankind from the excessive development of natural resources. Finely ground brick cullet has pozzolanic properties and can be used as an additive in a cement mixture, and a large fraction is used in aggregates of cement compositions.

Keywords: Сlay brick scrap, renovation, preparation, pozzolanic activity, hydraulic activity, binder, hardening, aggregate, mortar, strength

A study was made of aggregates used for the production of decorative concretes. Since slabs of these concretes are planned to be used for floors and platforms that are subject to high mechanical stress, aggregates must have the necessary properties. The resistance of crushed stone to impact on a copra, abrasion in a shelf drum and frost resistance were studied. For sands used as aggregates, such characteristics as granulometric composition, particle size modulus, stability of the stabilized mixture, etc. were determined. According to the results obtained, aggregate samples were determined that are most suitable for the production of decorative concrete, which are used for the installation of decorative floors and platforms.

Keywords: wear-resistant materials, decorative effect, size modulus, crushed sand, crushed stone

Hardening of concrete in the conditions of a construction site under constantly changing temperature and humidity conditions does not provide the desired performance properties of concrete and reinforced concrete structures. An assessment was made of the influence of the conditions of hardening of concrete samples at a water-cement ratio (W / C) of 0.45 and a hardening of 28 days. The hardening of concrete samples took place under conditions of a normal hardening chamber (air temperature T = 20 ± 50С, humidity W = 90 ± 2%), samples in water when completely immersed in a bath at water temperature T = 20 ± 30С and samples immersed in a plastic bag , hardening in the conditions of the air environment of the laboratory (T=20±50C). The samples gain the greatest strength when hardening completely immersed in water, and the smallest when hardening in an insulating polyethylene sheath.

Keywords: concrete scrap, fractionated crushed stone, water-cement ratio, hardening conditions, clinker hydration, strength development kinetics, moisture migration

The hardening of steel-making slags is slow and the strength properties of the cement stone do not provide the specified operational properties. By creating an optimal composition (steelmaking slag + blast furnace) and chemical activation, a composite material with high strength is obtained. The compressive strength of concrete samples at the age of 28 days of hardening in a normal hardening chamber is 28 to 54 MPa. Caustic soda and sodium silicate were used as a chemical activator of hardening. The greatest strength is provided by the ratio of chemicals as NaOH: Na2 SiO3 × nH2O = 1: 1 and at a dosage of 8% of the mass of the composite slag-alkali binder. The optimum ratio of ground granulated blast furnace slag and steelmaking slag is 3: 1 to obtain high compressive strength and minimum water absorption in the early stages of hardening.

Keywords: steelmaking slag, blast furnace slag, homogenization, hardening activator, hydration, strength

Experimental studies were conducted on the selection of rocks whose properties would satisfy the requirements for decorative concrete blocks made from them. Such properties as decorative effect, compressive strength, water absorption, abrasion resistance, impact resistance, frost resistance, etc. were evaluated. The properties of fine aggregate were also evaluated, from carbonate rocks — sand. Based on the work carried out, proposals were developed for a rational selection of the composition of decorative concrete

Keywords: decorative features, abrasivity, marbled limestone, frost resistance, aggregates

Up to now, the problem of recognizing printed characters of different fonts with high speed and reliability is not solved. The team of authors carried out research of images of printed characters of different fonts for the purpose of revealing the signs necessary and sufficient for recognition of signs by a computer. These features were a certain combination of directions, formed by elements of the contours of signs. According to the developed program for the computer, the image of each printed character stored in the computer's memory device was scaled up, uncharacteristic signs of signs, certain defects were eliminated and the contour of the sign was highlighted. The contour was represented in the form of a sequence of definite directions formed by its elements. All printed characters of the Russian alphabet of different fonts were recognized by a certain technique, despite the different types of printed fonts, for certain possible defects.

Keywords: printed sign, direction, standard view, recognition, outline, font, tag, serif, reading device, information