In this paper we consider some problems of economics and organization of construction which can be solved by linear programming method. In the first problem it is required to determine the set of construction machines for excavation of given amount of soil to minimize the cost of work execution. In the second problem the earth is transported from two pits and it is required to determine how much earth must be digged from each of the two pits to provide for the minimum cost of transportation.

Keywords: soil excavation, sand, crushed stone, minimum cost, linear programming, two-phase simplex-method

Storage of volatile and flammable liquids is carried out, as a rule, in vertical steel tanks. In total storage, they make up more than 80%. That is why research in this area is important in industry. The issue of reducing the cost of manufacturing tanks and reducing material costs during construction is extremely relevant. Based on the dependences of the optimal diameter, height and mass of the hull on the volume of the vessel, calculations were made for the existing TVS-10.000. In this paper, we considered a method for optimizing the size of a tank from the condition of minimum material consumption of the housing.The main dependencies and formulas were derived, on the basis of which the calculation was performed. When making calculations, the effect of static load was taken into account without the influence of dynamic factors. Thus, there was a decrease in material costs by about half for the cylindrical wall, cover and bottom.

Keywords: vertical steel tank, important in industry, reducing manufacturing costs, reducing material costs, optimizing sizes, method of optimizing sizes, minimal material consumption

Geopolymers are a promising building material that can become an alternative to Portland cement. They are distinguished by the possibility of using industrial waste, in particular metallurgical slags as well as inexpensive liquid glass. These resource-efficient binders can be used for the production of concrete products in stationary factories or workshops. The paper provides general directions for regulating the structure formation and properties of geopolymers based on metallurgical slags mixed with activators. The mechanism of geopolymer hardening based on the interaction of non-active slag components with an alkaline activator is briefly described; it is a three-stage physical and chemical process that leads to the formation of a solid stone structure. The influence of raw material properties on the final product characteristics is described.

Keywords: geopolymer, geopolymer concrete, aluminosilicate component, alkaline activator, metallurgical slag, basicity modulus, strength

This paper presents results of development of heat-resistant dielectric composite material based on epoxy resins to create structural and electrical radio products, coating materials receiving and transmitting radio systems for the aerospace, naval and land equipment. Research results show that when adding 10 wt.h. polyethylene polyamine as a hardener, 10-30 wt.h. polymethylphenylsiloxane as a modifier to ensure homogeneity, 10-40 wt.h.ceramic hollow microspheres and 5-15 wt. h. alumina as fillers per 100 wt. h. epoxy resin can be obtained a material with low permittivity and high thermal stability at 150 °C.

Keywords: dielectric material, polymer binder, epoxy resin, polyethylene polyamine, polymethylphenylsiloxane, hollow ceramic microspheres, heat resistance, permittivity

The article is devoted to the relationship between the strength of cement composites and the fractal dimension of their structure. In solid state physics, fractal algorithms can accurately describe and predict their properties and can be used in modeling the structure of composite building materials. Determination of the material fractal dimension according to its structure image at the macrolevel allows to understand its microstructure, and its properties as the result. Using the methods of experiment mathematical planning, the study was carried out and the relationship between the strength of the cement composite and its fractal dimension was established. It has been found out that the lower the fractal dimension, the higher the strength of cement composites. However, there is an area on the function graph that shows the increase in strength at sufficiently large values of the fractal dimension. Presumably, this is due to a change in the parameters of material differential porosity. For example, such as the average pore size index, the coefficient of pores uniformity in size, and the coefficient of microporosity. Such circumstance arouses interest and conditions for further research.

Keywords: fractal dimension, microstructure, strength, cement composite, composite building material, experiment planning, three-component system, regression equation, regression coefficient

The study is set to determine room's air exchange scheme's influence on exhaust ventilation appliances' effectiveness. Open-type exhausts (exhaust ventilation hoods) used in different industrial manufacturing processes are selected. In particular, a food processing working space with an adjacent meat heat-treating chamber, where ventilation hood is installed near an open doorway, is evaluated. Two options of supply air ducts' installation (air inflow in the center of a working space or, alternatively, side areas of it) are analysed. Geometrical models of heat-treating chamber, raw material loading room, ventilation hood placed over chamber's door, and supply air duct with air-distributing appliances are constructed. The article presents results of numerical simulation for the model of heat-treating chamber's exhaust ventilation system operation. It is established that, in case of a supply ducts' installation in a side areas of a room, an air exchange could be lowered by 28% under condition of a removal of a gas-air mixture without breaching into the room.

Keywords: exhaust ventilation, ventilation hood, simulation, heat-treatment chamber, numerical experiment

The article presents an analysis of the impact of fine dust particles on the health of builders, released during the production of construction processes and suggests measures to reduce it. A serious threat to the health of workers on the construction site and people living in the vicinity of it is represented by fine dust particles in a suspended state, both in themselves and in the total concentration of harmful air pollution near construction production. Analysis of the monitoring of suspended matter concentrations has shown that the ratio between the time of exposure to suspended dust particles in different concentrations directly affects the health of people. Air pollution in the work area negatively affects performance, causes diseases in workers, and can cause injuries due to reduced visibility. The organization of conditions corresponding to labor protection and safety, healthy environmental conditions on the construction site will ensure an increase in labor productivity by up to 12% and improve the quality of processes performed.

Keywords: environmental safety, environmental monitoring, air protection, ecology in construction, dust suppression, dust deposition, dust collection systems, labor protection in construction