Vol. 15, Number 2, 2019

Valeriy Bratchun, Vitaliy Bespalov, Denis Gulyak, Olga Narygnaya, Vladislav Goryainov
Temperature Conditions of Production and Compactibility of Asphalt-Polymer Concrete Mixtures with a Complex-Modified Structure 
Donbas National Academy of Civil Engineering and Architecture
Abstract. Asphalt polymer mixtures with a complex-modified microstructure are distinguished by increased workability and compaction in a wider temperature range (60…130 °C) compared to traditional hot asphalt concrete mixtures. This is facilitated by the thixotropic properties of the modified asphalt binder, the more developed adsorption-solvate layers of bitumen-polymer binder on the surface of mineral materials, and the flatter temperature and viscosity dependence of the asphalt binder. Complex modification of micro-, meso-and macrostructure of asphalt-concrete mixtures with ethylene glycidyl acrylate allows to significantly extend the temperature intervals of laying and compaction of concrete mixtures with organic binders, and thus extend the construction season and increase the range of mixtures, increase the durability of non-rigid pavements.
Keywords: complex-modified ethylene glycidyl acrylate asphalt-polymer-concrete mixture, temperature of mixture production, temperature range of compactibility.

Nelly Kolosova, Svetlana Monakh
A Mathematical Model of Heat and Mass Exchange in Biogas Producing in a Digester 
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article discusses issues of heat and mass transfer in the digester in the production of biogas by fermenting biomass. Thermal power for heating the fermented biomass depends on various factors, one of which is the presence of deposits of the solid fraction of the substrate on the heating element of the digester. Also, the mechanism of heat transfer from the coil to the fermentation mass is affected by the bubbling of the released gas from the mass itself. The article describes the processes of heat transfer from the heating element to the fermented mass in the absence of bubbling and taking it into account. The developed mathematical model of heat and mass exchange makes it possible to determine effect of the thickness of the deposits on the coil on intensity of heat emission from the heating coil to the fermented mass with and without bubbling.
Keywords: a digester, temperature regime, heat and mass exchange, heat transfer intensity, heat-emission, bubble.

Vitaly Datsenko
A Reduction of Metal Consumption of Construction Machine Parts Based on their Strength Analysis in APM FEM Environment 
Donbas National Academy of Civil Engineering and Architecture
Abstract. The paper discusses the issue of compliance of the results obtained in the strength calculations using computer-aided design systems, traditional techniques described in the educational literature, for example, traverse hook suspension bridge crane with a capacity of 20 tons. The possibility of optimizing the design parameters of parts of construction machines, based on their strength analysis. Comparison of the results of strength calculations performed in the APM FEM environment and traditional design techniques showed the possibility of optimizing the part by reducing its metal consumption without deteriorating its performance and reliability. In particular, for the traverse of the hook suspension with a slight increase in stresses and a decrease in the safety margin, it was possible to reduce the metal intensity by more than 40 %. However, despite the fact that in the strength analysis using APM FEM, in both cases, the calculations were carried out before reaching their convergence within 5…10 %, it cannot be said that it guarantees 100 % adequacy of the obtained results, in order to establish them experimental studies..
Keywords: strength analysis, computer-aided design, stress, safety factor, hook suspension, traverse..

Ekaterina Verekh-Belousova
Evaluation the Radiation Factors of Mine Dump of Luhansk Region using in the Building Materials Production 
Luhansk Taras Shevchenko National University
Abstract. Evaluation the prospects of Luhansk region’s coal mines dumps using in the building materials production by the radiation factors was performed in the paper. The work has carried out an assessment of the prospects for the use of dump rocks in the construction industry from radiation indicators. The specific effective activity of natural radionuclides in the five coal mines waste dumps of Luhansk region was determined by the gamma-spectrometric analysis. Was shown the waste rock can be used without restrictions in residential construction with such radiation characteristics. The laboratory method of de-termination the radon emanation coefficient in the rocks and materials was described. It allows estimating accurately the radon entry rate into the premises from walling materials at the design stage of a construction. Application of industrial mineral wastes – it one of ways of increase of efficiency of production of building materials and improvement of quality of environment.
Keywords: waste rock, uranium, radionuclides, radon, building materials, specific effective activity.

Tatyana Rafalskaya
Determination of Moisture Accumulations in Multi-Layer Enclosing Structures Based on Moisture Potential
Novosibirsk State University of Architecture and Civil Engineering (Sibstrin)
Abstract. Under operating conditions, the moisture content in the outer fences changes during the year, while in residential, public buildings, it usually increases in April and May, and in winter it is close to the annual average. Water accumulations play an important role in the design of the indoor microclimate, since they have a significant impact on heat loss and heat resistance of external fences. The application of the potential of humidity in the calculations of moisture transfer allows one to quantitatively take into account the moisture content in structures, both in vapor form and in the liquid and solid state, including the sorbed moisture and the area of supersorption moisture. This analysis allows to more fully taking into account the amount of moisture in building structures. Thestudy will improve the energy efficiency and energy saving of modern buildings.
Keywords: potential of moisture, external fences, moisture regime, moisture content, moisture accumulation.

Mikhail Samoylenko, Stanislav Malikov
Collapse Reasons Justification for Educational Building № 4 of Donetsk National University of Economics and Trade using Engineering Calculation Methods 
Donetsk PromstroyNIIproekt
Abstract. Collapse reasons justification for educational building № 4 of Donetsk National University of Economics and Trade are considered using engineering calculation methods. Simple calculation models for estimating the stress-strain state of structures are proposed. During complex calculations, it is more important to focus on targeting the correct calculation models then on accuracy and universality of the calculation methods. It has been determined that the collapse of building structures is a result of the following factors combination: incorrect design decisions, errors in construction and installation works, shortcomings of operation, lack of proper monitoring of building structures. It is shown that buildings with similar design solutions do not have a sufficient degree of reliability.
Keywords: survey, building, construction, calculation, collapse, causes of the accident.