Sergey Gorozhankin, Nikita Savenkov, Oleg Zolotarev
Analysis of the Operational Set of Operating Modes of the Automotive Power Plant using Variation Series
FSBEI HE «Donbas National Academy of Civil Engineering and Architecture»
Abstract. The article proposes an approach to presenting the operating conditions of a car in the form of variational series in terms of speed and required power, which form a joint characteristic. This allows you to divide the load-speed range of power plant operation modes into groups and rank them according to the total duration of the movement process. Such a uniform representation in the future will make it possible to simplify and develop a universal methodology for the integrated optimization of the regime and design parameters of motor vehicle power plants, depending on their purpose and operating conditions. The proposed approach is due to the relative complexity of the power plants of modern cars and the presence of many independent control parameters for the corresponding units. The need for the optimization under consideration is determined by the systematic tightening of environmental standards for emissions of harmful substances into the atmosphere, as well as the desire to reduce operating costs. As an example, the paper presents the results for a car of category N1 under the conditions of a standardized NEDC driving cycle. Using the Mathcad computer algebra system as an example, a simple algorithm is proposed for converting the studied dependencies into variational series with given parameters. The results obtained in the study can be used both for analysis, incl. comparative, actual modes of movement of cars, including driving cycles, and for solving problems of synthesis of advanced power plants, as well as algorithms for their control based on complex multi-parameter optimization, taking into account sets of driving modes in operation.
Keywords: power plant, driving cycle, power balance, variation series, vehicle speed, driving time, algorithm, option, interval.
Sergei Lakhtarina, Nikolai Zaichenko, Elena Egorova, Maksim Khlestov,
Nikolai Onopchenko
Modified Cements with the use of Industrial Waste from Donbass
FSBEI HE «Donbas National Academy of Civil Engineering and Architecture»
Abstract. The paper considers the complex effect of a mineral additivesas agglomerated silica fume of wet gas purification of the Stakhanov Ferroalloy Plant and limestone crushing of the Dokuchaevsky Flux-Dolomite Combine on the mechanical properties of cement. Compositions of effective modifiers (OMM) based on industrial waste, as a partial replacement of Portland cement, have been developed, the dependences of the degree of grinding of OMM in mill on the grinding time and composition have been established. It was found that when grinding silica fume (OMM 5), agglomeration of its particles occurs, which is confirmed by an increase in the specific surface area by more than 50 % relative to the composition of OMM 1. Binder compositions have been developed to ensure the production of cement with a compressive strength at the design age of at least 60 MPa.
Keywords: cement, superplasticizer, mineral additive, silicafume, limestone.
Аnna Lischenko
Investigation of Alkaline Heat-Resistant Concrete Based on Ash and Slag Waste of the Zuevskaya TPP
FSBEI HE «Donbas National Academy of Civil Engineering and Architecture»
Abstract. The paper presents the results of a comparative study of the dependence of the compressive strength of alkaline heat-resistant concretes on the type of ash and slag waste from the Zuevskaya TPP, the concentration of the alkali solution and the duration of hardening under normal conditions, during steaming and autoclaving. It has been established that during hardening under normal conditions, the strength of concrete is insignificant and amounts to 2.8–10.5 MPa. With heat and moisture treatment, especially autoclave, it increases significantly. The brand of concrete based on the slag of the Zuevskaya TPP is 1.5–2 times higher than the brand of similar compositions based on fly ash. Based on the developed slag-alkali binders, steamed and autoclaved slag-alkali concretes of grades 100–200 and 300–400, respectively, were obtained. The change in the physical and mechanical properties of alkaline concretes based on slag at ordinary temperature, after drying and firing at a temperature of 1 000° С was studied. It has been established that alkaline heat-resistant concretes based on ground coal slag from the Zuevskaya TPP have increased heat-resistant properties. Thus, the possibility and expediency of using ground coal slag in the manufacture of alkaline heat-resistant concretes has been proved.
Keywords: slag-alkali binder, heat-resistant concrete, linear shrinkage, strength, slag TPP, steaming.
Ksenia Pyankova, Denis Vcherashniy, Sergey Korobkov
Experimental Studies of Mechanical Properties of Hardening Cement-Sand Mortar with Different Water-Cement Ratio under Temperature Gradient
FSBEI HE «Tomsk State University of Architecture and Civil Engineering»
Abstract. The article presents the results of a study of the strength characteristics of a rod made of a cement-sand mixture with a certain ratio of water and cement (V/C = 0.4; 0.44; 0.49 and 0.54), which hardens under temperature gradients. The purpose of this study is an experimental study of the effect of temperature gradients on the mechanical properties of a hardened cement-sand mortar with a changing ratio of water and cement. The study showed that the increase in the strength of cement-sand cube samples varies in intensity during different periods of solidification and testing. It was found that temperature gradients (+60… (–20))° С have a significant effect on the solidification of cement-sand samples-cubes. After 8 hours of hardening, there is a tendency to increase the accumulation of strength, starting with the 5th sample. It can be expected that with further hardening time, the tendency to non-monotonic hardening will be more pronounced. The study of these processes will help to better understand the degree of negative impact of temperature changes on concrete structures and subsequently develop measures to increase their service life.
Keywords: temperaturegradient, cementstone, masstrans.