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  • 1
    Online Resource
    Online Resource
    Trans Tech Publications, Ltd. ; 2020
    In:  Solid State Phenomena Vol. 299 ( 2020-1), p. 169-174
    In: Solid State Phenomena, Trans Tech Publications, Ltd., Vol. 299 ( 2020-1), p. 169-174
    Abstract: Cement-free binding materials are a promising type of materials. The relevance and the possibility of increased efficiency of these materials are reasoned by environmental and technical-economic conditions of the current state of building industry. As a result of research, the following effect was established: polyvinyl alcohol on cement-free highly concentrated aluminosilicate binder suspension, obtained from granio-diorite screenings, increases the stability of structure-forming processes, due to the formation of associates and binding particles in the form of bulk network structures, that create a frame. Polyvinyl alcohol plays the role of a non-ionic regulator of the dimension and stability of these emerging structures, that determine and control the properties of the material, as a whole.
    Type of Medium: Online Resource
    ISSN: 1662-9779
    URL: Issue
    Language: Unknown
    Publisher: Trans Tech Publications, Ltd.
    Publication Date: 2020
    detail.hit.zdb_id: 2051138-3
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  • 2
    In: Materials Science Forum, Trans Tech Publications, Ltd., Vol. 1017 ( 2021-1), p. 153-162
    Abstract: The increasing urbanization of urban areas poses the challenge of the development of materials capable of self-cleaning from organic pollutants formed. Previous papers substantiated the possibility of the coating of titanium oxide as the main agent of the photocatalytic method of cleaning structural materials on silica raw materials in order to increase the degree of its distribution in the volume of cement matrix and, as a result, increase its efficiency.It is obvious that a silica substrate will affect the processes of structure formation during hardening of a cement matrix. During the research, the processes of phase transformations of cement stone modified with silica raw materials of natural and technogenic origin were studied. As a result, the influence of siliceous modifiers on the strength characteristics of the cement stone was determined, which allowed ranking them according to the degree of decrease in efficiency as follows: technogenic raw materials; natural raw materials of silicate composition; natural raw materials of aluminosilicate composition. Quantitative assessments of the degree of efficiency showed the irrationality of using aluminosilicate composition as a silica modifier of natural raw materials, which is explained by its low pozzolanic activity.
    Type of Medium: Online Resource
    ISSN: 1662-9752
    URL: Issue
    Language: Unknown
    Publisher: Trans Tech Publications, Ltd.
    Publication Date: 2021
    detail.hit.zdb_id: 2047372-2
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  • 3
    Online Resource
    Online Resource
    Trans Tech Publications, Ltd. ; 2021
    In:  Materials Science Forum Vol. 1040 ( 2021-07-27), p. 153-158
    In: Materials Science Forum, Trans Tech Publications, Ltd., Vol. 1040 ( 2021-07-27), p. 153-158
    Abstract: The paper presents the results of the determination of the effect of a photocatalytic composite material (PCM) with the composition SiO 2 ‒TiO 2 on the main properties of white Portland cement: heat release during hydration, phase composition and microstructural features of cement stone, pressure strength and self-cleaning ability. PCM was synthesized by a sol-gel method based on tetrabutoxytitanium and finely dispersed diatomite powder and 15% cement was added instead. The presence of PCM in the cement system provided the reduction of the induction period of cement hydration, consolidation of the microstructure of the cement stone with the products of the pozzolanic reaction, the ability to photocatalytic self-cleaning of the cement stone surface.
    Type of Medium: Online Resource
    ISSN: 1662-9752
    URL: Issue
    Language: Unknown
    Publisher: Trans Tech Publications, Ltd.
    Publication Date: 2021
    detail.hit.zdb_id: 2047372-2
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  • 4
    Online Resource
    Online Resource
    Trans Tech Publications, Ltd. ; 2020
    In:  Materials Science Forum Vol. 1011 ( 2020-9), p. 44-51
    In: Materials Science Forum, Trans Tech Publications, Ltd., Vol. 1011 ( 2020-9), p. 44-51
    Abstract: The complexity and a large number of variable factors of the bacterial carbonate mineralization process in the cement stone system, which is a polylineal and polydisperse system, has led to the question of each component’s role in bio consolidation processes. For carbonate biomineralization occurring in cement concrete during its restoration, it is impossible to fully describe the bio consolidation mechanism without studying the effect on individual components of the cement system (aggregate and binder). In the environment of quartz sand (the most common type of aggregate in cement concrete) there is no direct source of calcium, which is found in cement stone, which excludes the influence of abiotic factors (alkalinity of the medium) on the calcium carbonate production by bacterial cultures. This article presents the results of the study of carbonate biomineralization by urolithic bacterial cultures in a filler medium, in which quartz sand of three fractions (1.25–0.63; 0.63–0.315; 0.315–0.16) was used to assess degree and intensity of induction processes. As a result of the study, the physical and chemical factors of the bacterial carbonate mineralization process intensification in quartz sand samples were established. The time boundaries of the appearance of a consolidated layer were revealed within two fractions (0.63–0.315 and 0.315–0.16), which are directly related to the penetration depth of the solution with precursors and the bacterial inoculum by the percolation method. The analysis of the cemented layers’ microstructure is carried out, the features of neoplasms are considered. The type of bacterial culture that exhibits the most active cementing properties - Bacillus pumilus (VKM B-23).
    Type of Medium: Online Resource
    ISSN: 1662-9752
    URL: Issue
    Language: Unknown
    Publisher: Trans Tech Publications, Ltd.
    Publication Date: 2020
    detail.hit.zdb_id: 2047372-2
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  • 5
    Online Resource
    Online Resource
    Trans Tech Publications, Ltd. ; 2021
    In:  Materials Science Forum Vol. 1017 ( 2021-1), p. 11-20
    In: Materials Science Forum, Trans Tech Publications, Ltd., Vol. 1017 ( 2021-1), p. 11-20
    Abstract: Silicate micro- and nano-additives are multifunctional in relation to cement systems. Their application can solve a wide range of technological problems while maintaining the economic efficiency of technical solutions. The effect of silicate additives and fillers is determined by their level of dispersion, due to which the technologies for producing nano- and submicro-sized dispersed materials are being developed. The combination of mechanochemical synthesis of modified calcium hydrosilicates with subsequent thermolysis makes it possible to produce calcium silicate dispersions (SCD), which differ in polymodality of the fractional composition including submicro (10 –7 –10 –6 m) and microdimensional (≥10 –6 m) modes. The main element of the technology is the use of modifying carbohydrate, which acts as a stabilizer of hydrated phases of silicates. A comparative study of SCD produced using sucrose (sSCD) and lactose (lSCD) revealed the effect of these carbohydrates on the properties of sSCD and lSCD, as well as their effectiveness as a component of cementitious composite binder. It was found that the level of adsorption of modifying carbohydrate determines the physical properties of SCD (granulometry, specific surface area). The relatively high residual content of free sucrose (0.24%) in the composition of sSCD prevents the consolidation of silicates nanoparticles formed during the thermolysis, causes a high content of submicro sized fractions and a high specific surface area with sSCD (26.3 ± 0.7 m 2 /g). Lactose is absorbed by the silicate phase; the residual content of free lactose does not exceed 0.028% of lSCD. The low content of stabilizing carbohydrate contributes to the development of nanoparticle consolidation, a decrease in the specific surface area of lSCD to 13.0 ± 0.2 m 2 /g and content of submicrosized fractions. The residual content of free carbohydrates and particle size characteristics of sSCD and lSCD determine the nature of their influence on Cement-SCD-based concrete setting and hardening. The presence of residual sucrose in the composition of sSCD and fine fractions determines the competitive nature of the processes of retardation of hardening and acceleration of hardening of the cement system due to the nucleation effect, as a result of which the curve of the setting time is extreme. In addition, the inhibitory effect of sucrose reduces the strength of concrete on the 7 th day. By the 28 th day, the inhibitory effect of sucrose has been overcome, and concrete samples demonstrate an 18% increase in compressive strength with a sSCD content of 30%. The low content of residual free lactose in the composition of lSCD causes the nucleation effect. As a result, there is a monotonous reduction in the setting time of concrete mix with an increase in the content of lSCD in the composition of HF, as well as a significant increase in concrete strength (up to 127%) on the 7 th day. At the same time, on the 28th day the strength of concrete increases slightly
    Type of Medium: Online Resource
    ISSN: 1662-9752
    URL: Issue
    Language: Unknown
    Publisher: Trans Tech Publications, Ltd.
    Publication Date: 2021
    detail.hit.zdb_id: 2047372-2
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  • 6
    In: Construction and Building Materials, Elsevier BV, Vol. 248 ( 2020-07), p. 118699-
    Type of Medium: Online Resource
    ISSN: 0950-0618
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2020
    detail.hit.zdb_id: 2002804-0
    detail.hit.zdb_id: 58896-9
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  • 7
    Online Resource
    Online Resource
    RIOR Publishing Center ; 2023
    In:  Construction and Architecture Vol. 11, No. 2 ( 2023-06-27), p. 5-5
    In: Construction and Architecture, RIOR Publishing Center, Vol. 11, No. 2 ( 2023-06-27), p. 5-5
    Abstract: The program "Digital Economy of the Russian Federation", approved by the Government of the Russian Federation, is being actively implemented in the building construction industry, mainly at the stages of engineering surveys and architectural and construction design. Building information modeling (BIM) technologies are used by most foreign and domestic CAD system vendors. At the other stages of the building's life cycle, digitalization has not been widely distributed, despite the fact that the operation stage is the longest and the trouble-free existence of building structures at this stage is the key to the economic and social efficiency of building ownership. Flat rolled roofs in our country are the most common type of roofs and at the same time the most susceptible to defect formation structural element of a building. The standard operation period of such roofs is 10 years, despite the fact that the actual period of trouble-free operation of flat rolled roofs rarely exceeds 7 years. The assessment of the technical condition of the roofs is carried out by a construction and technical expertise, performed, as a rule, after the occurrence of leaks. Assessment of the degree of damage, as well as the prevalence of defects, is carried out by an expert visually, often without the use of measuring equipment. Due to the fact that the assessment of damage by an expert is purely subjective, it is impossible to correctly assess the development of the defect over time. The proposed technology of automation of construction and technical expertise of flat rolled roofs of a building allows timely detection of defects, assess the degree of their danger and make forecasts of their development over time. This approach allows you to make a timely decision on the need to carry out current repairs or to plan their implementation in the future. This will increase the service life of a flat rolled roof without increasing the cost of the life cycle.
    Type of Medium: Online Resource
    ISSN: 2308-0191 , 2500-1477
    Uniform Title: Интеллектуализация строительно-технической экспертизы кровель как инструмент управления ее жизненным циклом
    URL: Issue
    Language: English , Russian
    Publisher: RIOR Publishing Center
    Publication Date: 2023
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  • 8
    In: Nanomaterials, MDPI AG, Vol. 11, No. 4 ( 2021-03-29), p. 866-
    Abstract: Compositions and technology for obtaining a photocatalytic composite material (PCM) by deposition of titanium dioxide particles synthesized by the sol–gel method on a silica support of various types (microsilica, gaize and diatomite) have been developed. The properties (chemical and mineral composition, dispersion, specific surface area, porosity, ζ-potential, acid–base properties, and microstructure) of microsilica, gaize and diatomite were studied to assess the effectiveness of using a photocatalytic agent as a carrier. In terms of specific viscosity (ηsp = 45), the concentration of the precursor (tetrabutoxytitanium—TBT) is set at 22 vol. % in a solvent (ethanol), at which it is possible to obtain the maximum amount of dissolved film oligomer without the formation of an aggregate-like precipitate. Modification of the reaction mixture (precursor: ethanol = 1:3) by replacing part of the solvent with a Span-60 surfactant/TBT = 1–1.1 made it possible to obtain polydisperse titanium dioxide particles with peak sizes of 43 nm and 690 nm according to laser granulometry data. Taking into account the interaction of titanium complexes with the surface of a silica support, a phenomenological model of the processes of structure formation of a photocatalytic composite material is proposed. By the value of the decomposition of rhodamine B, the photocatalytic activity of the developed composite materials was determined: PCM based on diatomite—86%; PCM based on microsilica—85%; PCM based on gaize—57%.
    Type of Medium: Online Resource
    ISSN: 2079-4991
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2662255-5
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  • 9
    In: E3S Web of Conferences, EDP Sciences, Vol. 410 ( 2023), p. 01011-
    Abstract: The paper considers the dependences of the properties of self-cleaning fine-grained concrete on the composition of the concrete mixture: the ratio of sand to white Portland cement, the content of plasticizer, the content of photocatalytic composite material. The photocatalytic composite material (PCM) is a diatomite-based anatase-silica material obtained by sol-gel deposition of nanoscale TiO 2 of anatase modification on a silica carrier. The investigated properties of fine-grained concrete were: average density, compressive strength and self-cleaning ability, which was determined by evaluating the photocatalytic decomposition of an organic dye – Rhodamine B. It was shown that an increase in the content of PCM to increase the ability of the coating to self-cleaning leads to a loosening of the structure of fine-grained concrete, but this can be successfully offset by an increase in the content of plasticizer, which additionally improves the distribution of the photocatalytic agent in the cement-sand matrix. An increase in the proportion of sand and the content of plasticizer also contribute to an increase in the ability to self-cleaning. The pozzolan activity of the PCM provides an increase in the strength of concrete. The results of comparing the self-cleaning ability of fine-grained concrete of various compositions indicate a high photocatalytic activity of samples with PCM, which allows its application for creating self-cleaning coatings.
    Type of Medium: Online Resource
    ISSN: 2267-1242
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2023
    detail.hit.zdb_id: 2755680-3
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  • 10
    In: Buildings, MDPI AG, Vol. 11, No. 6 ( 2021-06-03), p. 239-
    Abstract: In this research, a phase formation in CaO–SiO2–Al2O3–H2O binding system under hydrothermal conditions was studied. The novelty of this article lies in the quantitative full-profile X-ray diffraction (XRD) analysis used to determine kinetics of mineral formation in the binder system “lime–granite mineral modifier (GMM)”. The formation of a polymineral system is described in detail, as well as quantitative relationships between mineral composition of newly formed phases and the binding mixture ratios were determined. Phenomenological model of mineral formation in a “lime–GMM” system under hydrothermal conditions was proposed. The results obtained allow the demonstration of this binding system as a binder that is characterized by superposition of hydration and geopolymerization. The properties (strength, density, water absorption, porosity) of compressed autoclave-hardened materials with the addition of a granite modifier introduced instead of part of the sand as an aggregate have been studied. The maximum increase in strength (more than 50%) is observed at a modifier content of 15%. This is due to the formation of a rational composition of neoplasms, the compaction of the structure of the pressed products and the optimization of their pore space, which is confirmed by the data of X-ray diffraction analysis, scanning electron microscopy and the method of gas adsorption.
    Type of Medium: Online Resource
    ISSN: 2075-5309
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2661539-3
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