Nanotechnologies in Construction: A Scientific Internet-Journal

83-88

Authors: : Kosach A.F., Kuznetsova I.N., Rashupkina M.A., Pedun G.A.

Introduction. One of the promising areas related to formation of concrete structure on the basis of a mineral binder with specified performance properties employs the addition of ultradispersed fillers (nanomodifiers) to the binder composition. Wastes of quartz and hydro-removal ash are used as nanomodifiers. The presence of nanoparticles in the binder can significantly change the processes of hydration and hardening of the concrete mix. Materials and methods. Hydro-removal ash from Omsk combined heat and power plant 5 (CHPP-5), cement and quartz waste obtained from the production of highly pure quartz concentrate which acted as an enhancer of pozzolanic activity to hydro-removal ash were used as materials for cement stone on the basis of a quartzash-cement binder. Nanomodifier was obtained as a result of mechanical, mechanohydraulic (water) and mechanohydrochemical (water + Megalit S-3ML additive) activations. Activation of the quartz-ash mixture was carried out in a continuous-action rotary mill. The mechanical method provides only mechanical activation, and the mechanohydraulic method provides mechanical, hydraulic, turbulent and acoustic activations. The mechanohydrochemical method provides all actions of hydraulic activation including chemical one. Results. The article investigated cement stone on the basis of quartz-ash-cement binder (activated quartz waste and hydraulic ash from Omsk CHPP-5, cement). The technologies of activation of the quartz-ash mixture by increasing the specific surface of the dispersed phase for the production of quartz-ash-cement binder are considered. The obtained results of the weight distribution of particles of hydro-removal ash and quartz before and after activation show that the average size of the nanoparticle diameter is from 25 µm to 1.5 µm and specific surface is 967–7729 cm2 /g. Conclusions. The use of nanoparticles in a quartz-ash mixture allows increasing the strength characteristics of cement stone from 23 to 59%. The use of quartz waste from the production of high-purity quartz concentrate and ash hydraulic removal from Omsk CHPP-5 power plant with the introduction of the proposed technologies for their activation allows increasing the formation of cement stone on a quartz-ash-cement binder by increasing the package density and chemical activity of nanoparticles in the processes of phase formation of hydrate compounds, which will reduce intergranular space between non-hydrated cement grains and will improve physical and mechanical characteristics of cement stone

96-104

Authors: Loganina V.I.

Introduction. At present, when performing finishing and restoration work, more and more preference is given to dry lime mixes (DBM). Wide opportunities for the production of dry lime-cement mixes are opened up by the use of diatomite, which is both a dry mix filler and an active mineral additive. Previous studies have confirmed the effectiveness of heat treatment of diatomite. After firing at 600–800о C, activity increases when interacting with calcium oxide hydrate. This is explained by the fact that at 600–800о C clay substances are dehydrated to metakaolinite, which is characterized by increased reactivity. The properties of dry mixtures and compositions based on them are affected by the particle size of the components of the dry mixture. In this regard, it is of great importance to study the influence of the dispersion of the components of the dry mixture on the formation of the structure of the finishing compositions. Materials and methods. To study the active centers of the diatomite surface, we used the indicator method for determining the distribution of adsorption centers. Determination of the compressive strength was carried out on a DOSM-3-1 dynamometer on samples 3x3x3 cm in size at the age of 28 days of air-dry hardening of the compositions. The determination of the granulometric composition of the components of the dry mixture was carried out by the method of sedimentation analysis. Adsorption was estimated from the optical density measured with a PEC photoelectrocalorimeter. To study adsorption at the “liquid-solid” interface, the initial components of the dry mixture, lime and diatomite, were used. Results and discussions. Accordingto the data obtained, it was found that a particle size reduction of the dry mixture filler leads to an increase in the strength characteristics of lime-diatomite compositions.It was found that the introduction of C-3 additive into the water favorsincreasing dispersion of hydrated lime, improving plasticity finishing mixture and improving the physical and mechanical characteristics lime-diatomaceous compositions.It is proposed to introduce sulfate additiveinto the formulation of the aluminumdry mixture. Increase in the compressive strength of the finishing composition with addition of aluminum sulfate 1.5–2 times was observed. Conclusion. It has been determined that the developed dry mixture is highly competitive, in terms of technological and operational properties,withprototype. Moreover, the production of the proposed DBM is more economical due to the use of local raw materials and domestic additives

119-136

Authors: Belozerov V.V., Nikulin M.A., Belozerov Vl.V.

Introduction. Recently, the term “nature-like technologies” has appeared in the everyday life of scientists and politicians, which quite deservedly include the so-called alternative energy sources (sun, wind, heat). At the same time, despite the fact that installations using these sources are “seasonal” and low concentrated, their use is rapidly and haphazardly developing, and many economists and politicians mistakenly consider them as basics, misleading business. Based on the analysis of the epistemology of the origin of the term "nature-like technologies", this article shows the groundlessness, and even the harm of the rapid and unsystematic use of wind turbines. Evidence is given of the inconsistency of the "myths" that Nature cannot cope with the compensation of the economic activity of mankind, therefore, according to Academician Sergeyev S.M., President of the Russian Academy of Sciences, "reengineering of the technosphere" is required. At the same time, modern economic science is far from taking into account in his models of the assimilation potentials of the biosphere of regions and the functions of entropy production in them, preferring to model various “cycles and modes”, as well as calculate different “coefficients” in order to predict “crises and equilibria”, without taking into account the interaction nature and society. In this connection, a scientific and technical task about determinating the “place of reengineering of the technosphere” in the structure of the life support systems of society, and, consequently, to evaluate its effectiveness. Methods, models and tools. To solve the tasks set, it is proposed to use the “retro-forecast method” of socio-economic losses from the introduction of “natural nanotechnologies”, using as “tools” the method of “spatio-temporal analysis”, model of the Leontief-Ford and adaptive taxation systems of “harm production”, the use of which in solving the problems of fire and environmental safety in the "technospheres of the regions" of the South of Russia (in road transport infrastructures, in cities and towns, in buildings and structures), proved their adequacy to the processes under study and usefulness. Results and discussion. The results of modeling the costs of efficiency of "reengineering of the technosphere" in Russia, in particular individual residential buildings, and a retro-forecast of changes in socio-economic and environmental losses during the autonomy of their resource supply (electricity, water and heat) are presented. It is shown that the production of domestic innovations in this area (“Shukhov’s” wind turbines, atmospheric water condensation devices and electric heating) will allow stopping the “total gasification” of rural settlements, as well as more economically than abroad, to implement decentralized supply of resources in Russia more than 10 million individual houses and about 40 million country houses, thus determining the “true place of alternative energy” in the structure of the Russian systems of electricity, gas, water and heat supply. Conclusion. The proposed approach allows us to determine the place of the socalled renewable energy in the structure of resource supply systems for cities and rural settlements. At the same time, it is possible that the emergence of more productive design solutions of the proposed innovations in the field of wind energy and solar panels will expand the "autonomization" to low-rise and multi-apartment buildings in regional centers and workers' settlements, instead of a major restoration of centralized engineering systems with boiler houses and mini- CHP.

145-155

Authors: Balykov A.S., Nizina T.A., Volodin S.V

Introduction. The management of physical and chemical processes of structure formation of high performance cement composites can be provided at several scale levels through the use of modifiers of various nature and mechanism of action, in particular, micro- and nanoscale mineral additives of natural and technogenic origin. It is known that clays and carbonate rocks are promising raw materials to obtain mineral modifiers for cement systems. The purpose of this study was to establish the influence regularities of the prescription and technological parameters (material and granulometric compositions, temperature calcination) to obtain mineral additives based on calcined clays and carbonate rocks on their activity in cement systems. Methods and materials. Polymineral clays and carbonate rocks (dolomite and chalk) from several deposits of the Republic of Mordovia were used as raw materials for obtaining mineral additives. The specific surface area of modifiers was determined on the PSX-12 dispersion analysis device using the Kozeny-Carman method. The study of the granulometric composition of sedimentary rock powders was carried out by laser diffraction method. The research of physical-chemical processes occurring during the heat treatment of polymineral clays and carbonate rocks was carried out using the synchronous thermal analysis method. Optimization of calcination temperature of clay-carbonate mixtures was carried out based on the research results on the effect of their additives on the cement binder activity with the determination of the modifier activity index in accordance with the methodology of the Russian State Standard GOST R 56178-2014. Results and discussion. The optimum calcination temperature, located for polymineral clays in the area of 500–800оC, was established according to the study results of dehydration processes of clay minerals using the synchronous thermal analysis. This temperature range corresponds to the initial restructuring processes in the crystal structure of minerals of the kaolinite and illite groups, associated with their dehydroxylation, which contributes to the transition of these phases to the active form. The study results of influence of additives of calcined clay-carbonate mixtures on the cement binder activity proved the thermal analysis data. It was found that calcination of clays and clay-carbonate mixtures at 700°C contributes to obtaining of the most effective mineral modifiers. Conclusions. On the totality of studies, regularities were revealed in the system “modifier composition – calcination temperature of sedimentary rocks – mixed binder activity”, which allow optimizing the prescription and technological parameters for obtaining mineral additives to achieve the required level of strength characteristics of cement composites.