The influence of lithium carbonate on the heat release during the hydration of Portland cement at the temperature 40°C

This work represents the stage of the author's research aimed at identifying the solutions for increasing the energy efficiency of the production of precast concrete and reinforced concrete products and structures in plant conditions due to reducing the temperature of heat treatment, or due to the reduction of duration of this technological process. The work provides results of the research of the influence of the admixture of lithium carbonate (Li2CO3) on the dynamics of hydration process of the binding systems on a cement basis in the conditions of the increased temperature (40°C). The research was performed using the method of isothermal calorimetry on the two various samples of the cement binder, conducted in various countries. The Li2CO3 admixture is accepted in dosages from 0.5% to 2.5%. The graphical dependence of the heat flow of the exothermic reaction of hydration on the used lithium carbonate dosage in the first days of curing of the samples is established and presented

Priority Influence of Horizontal Forces at Rolling on Operation of Main Sheet Rolling Equipment

Horizontal force during unsteady rolling is considered with its calculation for 4-high rolling stands when rolling torques and rolling stands geometrical characteristics are known. Phenomenon of appearance of horizontal forces applied to work rolls preceding appearance of all other basic loads in sheet rolling mill stands and their main drive lines was theoretically and experimentally proved for different rolling mill stands

Flexibility and adaptability - key elements of end-user participation in living space designing

An end-user has the main role in the creation of space where spends most of its lifetime (home, workplace). That is why important that a designer (he first) recognizes what requests of the end-user are. In the reference literature and researches that deal with the spatial organisations and designing of living area, the role of an end-user is essential. However, what does the end user participation mean, actually? At what level an end-user makes a final decision? Is it a choice among several alternative solutions provided by an architect or end-user himself? This article precisely deals with that subject - where begins and where ends participation of the end-user when the theme is the final spatial solution and under what circumstances. In this case, habitation represents the much more sensitive area than any other area for human needs or activities. In technical terms, an end-user could be someone who either knows nothing or knows a lot but not enough about both the spatial and functional organisations. His role should be reduced to choice of one from the group of high-quality solutions and, in a technical sense, logical solutions made by an expert. No more than that

Optimization of process organization in monolithic construction Оптимизация организации производственных процессов монолитного строительства

Nowadays in Russian Federation there is a growing demand for monolithic construction. Monolithic construction technology is developing to meet the requirements, such as reduction of construction time and improvement of the quality of the structures. Analysis of different situations that arise on construction sites shows a number of usual problems: increased construction period, increased cost, etc.Possible reason of this problem can be in using outdated approaches to the control of monolithic construction processes. Such approaches do not take into account deviations due to the abrupt changes caused by external influence of the environment. And it can lead to increase in technological expectations or increase in labor costs for eliminating these deviations. This article presents an approach, which helps to increase the efficiency of process organization in monolithic construction by means of adaptive control and operative control in real time. This approach is based on the methods of operative monitoring and processing of information about the state of the production system at any given time. In this paper organizational scheme for combining different production and control processes was developed, which is based on the following principles: Choice of criteria for comprehensive assessment of a production system, that reflect both internal state and external disturbances; Development of the methods and means of operational monitoring of the structures(includes previously selected criteria); Development of the methods of constructing situation models of the production system functioning (including modeling the hydration process of concrete and the influence of external factors on this process).Development of the methods of research and information decision support based on automated processing of information, obtained in the course of monitoring, and on the analysis of available options of controlling actions.<br>Проанализированы современные тенденции развития монолитного строительства и предложен комплексный подход к оптимизации строительного производства, основанный на организации адаптивного управления производственными процессами с учетом мониторинга и оперативного анализа влияния внешних воздействий на рассматриваемую производственную систему

Flexibility and adaptability - key elements of end-user participation in living space designing

An end-user has the main role in the creation of space where spends most of its lifetime (home, workplace). That is why important that a designer (he first) recognizes what requests of the end-user are. In the reference literature and researches that deal with the spatial organisations and designing of living area, the role of an end-user is essential. However, what does the end user participation mean, actually? At what level an end-user makes a final decision? Is it a choice among several alternative solutions provided by an architect or end-user himself? This article precisely deals with that subject - where begins and where ends participation of the end-user when the theme is the final spatial solution and under what circumstances. In this case, habitation represents the much more sensitive area than any other area for human needs or activities. In technical terms, an end-user could be someone who either knows nothing or knows a lot but not enough about both the spatial and functional organisations. His role should be reduced to choice of one from the group of high-quality solutions and, in a technical sense, logical solutions made by an expert. No more than that

Principles of Sustainable Infrastructure Formation in Research and Technology Development Centers Construction

The paper concerns the issue of infrastructure formation in research and technology development centers. It is established that the key point in the design and construction of such centers is providing the effective functioning of social infrastructure, which is a connecting link for the main structural elements of modern research and technology development centers. The grounds for the necessity of working out a unified pattern for designing research and technology development centers in compliance with the urban planning regulations and research and technology development priorities are given. An integrated model for working out a unified pattern of designing research and technology development centers is suggested. This model envisages creating a harmonized international standard that describes the basic principles of sustainable infrastructure formation in research and technology development centers construction. Based on the research results, the principles of sustainable infrastructure formation in research and technology development centers are set out and worded according to the goals of sustainable development. The authors also give grounds for the applicability of the principles formulated in this paper for the infrastructure assessment of research and technology development centers, both operating and under construction, which will make it possible to target the less-developed elements and draw up the plan of their improvement for further sustainable development. The authors also list emerging technologies to be developed and implemented for the efficient accomplishment of the research objectives

Measures to reduce construction time of high-rise buildings

The organizational and technological solutions for high-rise buildings construction efficiency increase are considered, primarily – decrease of typical floor construction time and improvement of bearing structures concrete quality. The essence of offered technology is: a concrete mixing station and a polygon mainly for load-bearing wall panels with starter bars casting are located on the building site; for reinforced concrete components manufacturing and butt joints grouting the warmed-up concrete mixtures are used. The results of researches and elaborations carried out by the SPSUACE in area of a preliminary warming-up of concrete mixtures are presented. The possibility and feasibility of their usage in high-rise buildings and of excess height buildings construction including cast-in-place and precast execution are shown. The essence of heat-vibro treating of concrete mixture is revealed as a kind of prior electroresistive curing, and the achieved results are: accelerated concrete strength gain, power inputs decrease, concrete quality improvement. It is shown that the location of a concrete mixing station on the building site enables to broaden possibilities of the “thermos” method use and to avoid concrete mixtures warming up in medium-mass structures erection (columns, girders) during the high-rise buildings construction. It is experimentally proved that the splice between precast elements encased with warmed-up concrete mixture is equal with conjugated elements in strength

The modelling of power plant’s evaporative cooling tower operation taking into account hydrometeorological conditions

The paper aims to perform numerical modelling of the operation of large-scale evaporative cooling towers of power plants considering dynamically changing hydrometeorological conditions. The proposed modelling was performed based on the developed mathematical algorithm for studying the influence of turbulent vortex motions on the processes of atmospheric cooling of circulating water in countercurrent cooling towers of power plants. According to the simulation results, the optimal heat exchange modes of cooling towers operation are determined and recommendations for the practical implementation of measures to improve their thermal efficiency in hot periods of the year are proposed

About the Territorial Potential of the Construction of Battery-Charging Stations for Autonomous Electric Motor Vehicles in the Regions

The article describes the main current trends in the development of electric motor vehicles with "zero emission" as well as the battery-charging stations concerned. The study is based on a preliminary comparative analysis of the RF regions with respect to five indices (average per capita income, number of private cars in the region, air pollution level, provision of the region with power supply and the potential use of local renewable energy resources), and it gives some recommendations on the prospects of possible construction of battery-charging stations in the regions

Measures to reduce construction time of high-rise buildings

The organizational and technological solutions for high-rise buildings construction efficiency increase are considered, primarily – decrease of typical floor construction time and improvement of bearing structures concrete quality. The essence of offered technology is: a concrete mixing station and a polygon mainly for load-bearing wall panels with starter bars casting are located on the building site; for reinforced concrete components manufacturing and butt joints grouting the warmed-up concrete mixtures are used. The results of researches and elaborations carried out by the SPSUACE in area of a preliminary warming-up of concrete mixtures are presented. The possibility and feasibility of their usage in high-rise buildings and of excess height buildings construction including cast-in-place and precast execution are shown. The essence of heat-vibro treating of concrete mixture is revealed as a kind of prior electroresistive curing, and the achieved results are: accelerated concrete strength gain, power inputs decrease, concrete quality improvement. It is shown that the location of a concrete mixing station on the building site enables to broaden possibilities of the “thermos” method use and to avoid concrete mixtures warming up in medium-mass structures erection (columns, girders) during the high-rise buildings construction. It is experimentally proved that the splice between precast elements encased with warmed-up concrete mixture is equal with conjugated elements in strength