The developed technology of producing cements with biocidal properties and the results of investigating the physico-mechanical properties of the developed cements, cement pastes, and hardened composites are given. Data on the biostability of composites modified with sodium sulfate, sodium fluoride, and polyhexamethylene stearate are presented. Recommended biocidal binder compositions for manufacturing concretes and other cement composites are given.

Development of Biocidal Cements for Buildings and Structures with Biologically Active Environments

In recent years, both Russian and foreign researchers have paid considerable attention to the problem of ensuring the reliability of building structures at all stages of their erection and operation, reconstruction, repair and reorganization. This is due to the growing need to ensure reliable operation of unique, expensive, historically significant structures, which dismantling and replacement are much more expensive than repair or it is impossible generally. Damage to reinforced concrete structures, as a rule, is associated with corrosion, overloading of individual elements and improper operation, design and production errors. In this article, the process of examining the reinforced concrete bearing structure of the building overlap for the possibility of its reconstruction and reorganization is considered in detail, as well as the design calculation based on computer modelling in the LIRA-CAD program.

https://iopscience.iop.org/article/10.1088/1757-899X/463/4/042009/pdf

The Reliability of Building Structures Against Power and Environmental Degradation Effects

The construction industry has experienced the hugest number of changes during all century's history. Today in construction there is a huge set of scientific completions and innovative solutions that many times increase quality of works and process reliability of construction in general. This publication is devoted to an innovative element for strengthening building constructions and elements - to high-strength composite materials. Due to inevitable exhaustion of natural resources and increase in energy cost in the world the process of composite materials production in industrial is becoming more relevant, important and popular, such as fibreglass, basaltplastic, carbonoplastic. These composite materials possess sufficient characteristics on reliability, durability, profitability and that is the most important - environmental friendliness in comparison with the metal reinforcing elements. It is important that source replenishment of raw materials in modern production is possible due to processing of secondary raw materials and technogenic waste. Experience of using composite materials during strengthening building constructions, the comparative analysis from the point of ecology production and using materials, advantages of composite materials is reflected in this publication. The purpose of this publication is to show validity of using composite materials for strengthening building constructions from the point of view of reliability, profitability and also environmental friendliness in comparison with other reinforcing elements.

https://iopscience.iop.org/article/10.1088/1757-899X/365/3/032053/pdf

Technical aspects of using composite materials for strengthening constructions

Properties of new reinforcing element — composite reinforcement, are considered. Feasibility study of using this material for modernization of buildings, namely for vertical extension with additional storey, is carried out. Comparative analysis of performance is conducted for metal and composite reinforcement, as well as calculations are performed which results will be used for determination of advantages and disadvantages of this innovative reinforcing method. An important factor for development of projects of building vertical extension after quite a long operation period is a proper selection of construction materials and strength analysis considering the structures to be erected. Calculation of a floor slab erected with using composite fiberglass reinforcement is represented. Results obtained in the calculation and the analysis of the data prove high efficiency of this reinforcing method through the decrease of loads on lower storeys of the building, economic feasibility and other factors.

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Application of composite reinforcement for modernization of buildings and structures

Reliability and stability of transport facilities during their maintenance can be ensured by the application of the engineering and geodetic monitoring systems for deformation processes in structures supervision that allows avoiding emergencies. Nowadays, automatic engineering devices are successfully used in order to produce high-precision spatial measurements. Further development of deformation monitoring systems requires the development of software tools for deep analysis of structures based on data. The article considers the methodology and software for deformation monitoring of road transport structures and facilities using geodetic methods during construction, maintenance and reconstruction these structures in order to evaluate their technical availability and to prevent negative impacts on surrounding buildings and structures. In addition, it is reviewed the world’s researches on this subject, as well as practical examples of the application this methods.

Deformation Monitoring of Road Transport Structures and Facilities Using Engineering and Geodetic Techniques

The article considers innovative materials for construction. Using mathematical planning methods, we studied how the quantitative composition, the biocidal additive and gypsum content influence on the compressive and flexural strength and density of the composites. We found that the more gypsum in a composition the higher compressive and flexural strength of a specimen. So, with the greatest degree of compositions filling (fly ash – 20 mass fractions, gypsum – 11.2 mass fractions) maximum compressive strength is 72.5 MPa. We determined when the fly ash content rises up to 20 mass fractions per 100 mass fractions of clinker, flexural strength rises too and specimen density decreases. The developed compositions of biocidal cements recommended for use in the manufacture of materials, products and structures for buildings and constructions, operating in aggressive environments.

Physical and Mechanical Properties of the Cement Stone Based on Biocidal Portland Cement with Active Mineral Additive

/pdf/investigation-of-concrete-properties-of-reinforced-concrete-2z0itvk8qc.pdf

Investigation of concrete properties of reinforced concrete constructions of structures operated in the coastal zone of the Black Sea coast

The studies to establish the species composition of micro-mycetes inhabiting the surface of cement composites after aging in sea water have been carried out. Cement stone made on the basis of Portland cement clinker, a mineral additive and a fungicidal preparation was considered as the studied material. To determine the materials’ fouling by microorganisms, their species composition, imprints and sampling methods were used. A change in the species composition of mycobiota isolated from the cement composites’ surface modified with sodium sulfate and sodium fluoride depending on the amount of active filler, gypsum, and biocidal additives was experimentally revealed. The effectiveness of using the biocidal cement composites with an active mineral additive has been confirmed. It was found that the composites on the developed compositions showed higher resistance compared to the materials on ordinary cement. The compositions modified with biocidal additives showed a fungicidal effect.

Cement Composites’ Biostability

Porous glass-ceramic materials are used in the construction engineering and repair of various objects. The article investigates the method for obtaining porous glass ceramics from siliceous rock with a high calcite content. To obtain samples with an even fine porous structure, a small amount (≤0.386%) of chloride (NaCl, KCl, MgCl2·6H2O, CaCl2) was added to the charge mixture. At the first stage, mechanochemical activation of raw materials was carried out. Siliceous rock, Na2CO3 and additives (chlorides) were grinded together in a planetary ball mill. The resulting charge was annealed at a temperature of 850 °C. The influence of the type and amount of chloride on the properties of the charge mixture and glass ceramics has been defined by thermal analysis (TA), X-ray diffraction (XRD), scanning electron microscopy (SEM), etc. The chlorides in the charge mixture decreased the calcite’s decarbonization temperature and had an effect on the macro- and microstructure of the material. As a result, samples of glass ceramics with an even finely porous structure in the form of blocks were obtained. The samples consist of quartz, wollastonite, devitrite, anorthoclase and an amorphous phase. On average, 89–90% of the resulting material consists of with small pores. The apparent density of the samples is in the range of 245–267 kg/m3. Bending and compressive strength reaches 1.75 MPa and 3.8 MPa, respectively. The minimum thermal conductivity of the modified samples is 0.065 W/(m∙°C). The limiting operating temperature is 860 °C, and the minimum thermal shock resistance is 170 °C. The material has a high chemical stability. They can be used as thermal insulation for some types of industrial and civil facilities.

/pdf/effect-of-chlorides-content-on-the-structure-and-properties-3ro2cpwu.pdf

Effect of Chlorides Content on the Structure and Properties of Porous Glass Ceramics Obtained from Siliceous Rock

The article presents the results of the study of the structure, physical-mechanical and thermophysical properties of glass-ceramic materials. The charge mixture for the production of samples was obtained from siliceous rocks, kaolin, bentonite, Na2CO3 and KCl. Joint mechanochemical activation of the components was carried out in a planetary ball mill. The charge mixture obtained was fired in a muffle furnace at a temperature of 850 °C. The experimental results were obtained using the method of X-ray phase (XRF) analysis. The physical-mechanical and thermophysical properties of the samples are determined. The developed materials (in the form of blocks) have an apparent density of 308 to 409 kg/m3, flexural strength up to 3.2 MPa and compressive strength up to 13 MPa, thermal conductivity from 0.081 to 0.107 W/m∙°С, limiting operating temperature up to 890 °С inclusive. The materials obtained are superior in many respects to foam glass and glass ceramics from industrial waste. They can be used as thermal insulation in the construction of industrial and civil facilities.

Alexander Rodin

Papers

Physical and Mechanical Properties of the Cement Stone Based on Biocidal Portland Cement with Active Mineral Additive

Investigation of concrete properties of reinforced concrete constructions of structures operated in the coastal zone of the Black Sea coast

Cement Composites’ Biostability

Effect of Chlorides Content on the Structure and Properties of Porous Glass Ceramics Obtained from Siliceous Rock

Influence of aluminosilicates on the properties of porous glass ceramics from siliceous rocks