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  • Influence of mineral composition and structure of aggregates on thermal expansion of conventional and heat-resistant concretes

    The work was carried out due to the fact that the regulatory documents used in the design of structures operating at elevated and high temperatures do not take into account the peculiarities of the mineral composition and structure of concrete aggregates. This is a disadvantage of these documents, since the mineral composition and structure of aggregates can differ significantly even for materials of the same name, which can significantly affect the thermal changes in concrete. Due to the impossibility of experimentally investigating all the variety of concretes based on aggregates of various mineral composition and structure, a computational and analytical study was carried out in the work on the basis of existing methods for the analytical determination of thermal changes in concretes and their components. On the basis of these methods, the effect on the thermal expansion of concretes of the presence and amount in the aggregates of the most expanding minerals (aragonite, calcite, quartz, cristobalite, potassium feldspars, pyroxenes) and glass, as well as the average size of crystals composing mineral fillers, has been calculated and investigated. Considered are heavy Portland cement concretes on aggregates of limestone, dolomite, granite, syenite, diorite, basalt, diabase, broken clay brick, chamotte and slags. Based on the calculations, it has been established that the values of the thermal change in the volume of concrete, determined according to the normative document SP 27.13330.2017, coincide with the calculated values only for certain combinations of the mineral composition and structure of aggregates in terms of crystal sizes. In other cases, the actual thermal expansion of concrete may be less and more than the values obtained according to SP 27.13330.2017. The regularities of the influence on the thermal expansion of concrete of the content of various minerals and the average size of the crystals of minerals in the aggregates are established.

    Keywords: thermal expansion, conventional and heat-resistant concretes, aggregates, minerals, glass, the effect of the mineral composition and structure of aggregates

  • Analytical determination of thermal and radiation deformations of concretes and mortars with low aggregates content

    Experimental verification of the existing method of analytical determination of radiation and thermal deformations of concretes and solutions on the basis of data on deformations of aggregate and cement stone for materials with low content of aggregates is carried out. The test was carried out on samples of solutions with different content of aggregate-sand based on the results of determining the size changes after heating at temperatures from 105 ° C to 400 ° C. It is shown that at the volume content of fillers less than 52% there are differences between the calculated and experimental values of changes in the size of solutions after heating. Moreover, the differences increase with the decrease in the volume content of the filler, with an increase in the heating temperature and the difference between the thermal deformations of the filler and the cement stone. The obtained results allow to correct the results of calculations using the specified existing analytical method for concretes and solutions with a filler content of less than 52%

    Keywords: thermal and radiation deformations, solutions and concretes, analytical and experimental determination, filler content, microstructural stresses, cracking

  • Hardware-software complex process modeling shoot

    In this paper, the technology of process simulation shooting remote sensing the Earth's surface in the optical spectrum of the radiation on the software and hardware complex. With his help, describe and forecast the qualitative characteristics of shooting in the simulation with high resolution linear assessment on the ground.

    Keywords: remote sensing of the Earth's surface, software and hardware, virtual ground, the speed of movement of the image, panchromatic imagery, multispectral imagery, linear ground resolution

  • Methods and tools for modeling systems of remote sensing of the Earth from space

    In this article methods and tools for simulation of systems of remote sounding of the Earth's surface from space in the optical range of the radiation spectrum to optimize its structure and functional properties. The structure of complex information-measuring system of remote sensing to explore the experimental field through very difficult and very expensive in connection with the combination of various physical and technological processes occurring in it. The exit lies in the total use of natural and mathematical modeling with the use of modern IT-technologies, as the establishment phase and during the operational phase, with the aim of improving methods and design tools, as well as better control of equipment settings for advanced space systems (the free spectral range of physical intensity, linear resolution of the terrain and the performance of the system itself).

    Keywords: remote sensing of the Earth's surface, space system, the system receiving and converting the information lens, an optical reception system, the underlying surface of the Earth, remote sensing, linear ground resolution

  • Energy conservation during treatment of sewage from populated area

    At present an important role in solving energy conservation problem is assigned to thermal pumping plants (TPP). Using processes of evaporation and condensation of easily boiling liquid circulating in the system they extract low potential heat from environmental objects and provide heat supply for buildings, constructions, greenhousee and so on. Artificial sources of low potential heat for TPP of different capacity can be, for instance, ventilation air and exhaust gases, circulating and waste water,ground. Energy efficient reasonability of TPP use in the system of water disposal for the town of Novocherkassk in Rostov region is considered. Calculations indicate that there is a technical potential to replace a boiler house operating on expensive gas fuel and emissing into the atmospere more than 850 t of carbon dioxide - greenhouse gas - with ecologically clean TPP, one of which uses heat of waste water and the other - heat of ground.

    Keywords: thermal pumping plant, renewable sources, energy conservation, evaporation, condensation, waste water, ground