No 3 (2024)

The main requirements for modern housing are accessibility, quality and aesthetics. In construction, new requirements arise for the technology of manufacturing structures: a free layout with a ceiling height of 2.7 m or more; column pitch of 6 m or more; ceiling height of the first floor up to 8 m; a high degree of factory readiness and architectural aesthetics of the exterior walls. At the same time, it is necessary to ensure a reduction in the weight of structures per 1 m² of building area and an increase in installation speed. All these requirements can be fulfilled by the Recon technology, known in the practice of the construction industry in Russia and neighboring countries, which produces pre-stressed floor slabs up to 7.65 m long and unstressed floor slabs up to 7.2 m or more; efficiency structures, internal walls (IW) and external walls (EW) on universal stands 3.6; 4; 5.2 m × 60, 90, 120, 128 m in automatic mode, starting with laying concrete using targeted feeding, automatic vibration of the stand surface, grout of the upper surface and automatic heating of the stand. It is important to note that during the hydration of cement stone, the concrete laid on a universal stand does not move either horizontally or vertically, thereby ensuring high quality and density of the product.

The advantage of frame buildings of socio-cultural purpose for the implementation of any social and commercial projects is noted. Proposals have been formulated to create a unified system of technical documentation that can be used by any designers, manufacturers of precast concrete and builders themselves for the entire construction complex of Russia. The main solutions of the RCD system (frame-link frame with diaphragms) are shown, examples of practical application of the RCD system are given. It is noted that the construction of buildings made of precast reinforced concrete, compared with monolithic construction, reduces the cost of construction by at least 20%; reduces construction time by more than half; reduces rebar consumption by at least 20%; reduces concrete consumption by at least 30%.

The results of experimental and theoretical studies of fiber reinforced concretes are presented. The purpose of the research was to establish physical and mechanical properties of self-compacting, carcass concrete and fiber reinforced concrete. When performing the research, white cement was used as a binder. As a reactive additive was used white carbon black BS-100. Plasticizing of the system was carried out by polycarboxylate SP. To increase the volume of dispersed phase, the combined filler from rheologically active fine ground rocks was used, namely: quartz flour R-6, and microcalcite RM-5. To form the filled structure of the composite we also used fine sand PB-150, and at the first stage steel microfiber “BMZ” and glass fiber «Antikrek sp» were used as dispersed reinforcement. Dispersed reinforcement with glass fiber 0,15 mm diameter and 18 mm long, with volume reinforcement of 0,8% increased the composite compressive strength by 13,4%, flexural tensile strength by 12,8%. Dispersed reinforcement with metal fiber of 0,15 mm diameter and 15 mm length, at volume reinforcement of 4,2% contributed to increase the compressive strength by 46,5%, flexural tensile strength by 186,6%. Further increase in the strength of fiber concretes is possible by strengthening the anchorage of fibers in the matrix. Therefore, at the second stage, the influence of different types of metal fibres, differing in shape and type of anchor, on the properties of dispersed-reinforced concrete was established. An increase in flexural and compressive strength from the introduction of dispersed reinforcement of “Spring”, “Wave” and “Dramix” types is shown. The assumption of efficiency from application of fiber of “dumbbell-like” form in modern reaction-powder composites, and also manufacturing of materials with application of frame technology, consisting at first in formation of a frame from glued grains of large aggregate and then in impregnation of its empty matrix component, is put forward. Comparison of calculated and actual strength of fiber concretes is carried out.

The article describes the relevance of new scientific research on the corrosion resistance of shotcrete applied as a protective coating on building structures. A formulation has been developed for five compositions of shotcrete, consisting of a basic and additional binder, fillers and hardening accelerators. The size and nature of the pores of the manufactured samples, the development of destruction by changes in mass and strength are investigated. The physicochemical features of the corrosive destruction of some shotcrete compositions in solutions of sodium sulfate and sodium chloride have been established, and the diffusion coefficients of chloride ions and sulfate ions have been determined. The numerical values of the parameters limiting the mass transfer of calcium hydroxide during corrosion of shotcrete are determined: the coefficients of mass conductivity and mass transfer.

19 марта 2024 г. В Москве компания КНАУФ организовала встречу ведущих журналистов отраслевых СМИ с членом управляющего комитета региона КНАУФ Россия и Беларусь Алексеем Сергеевич Зиминым, отвечающим за все аспекты деятельности по сбыту и маркетингу, а также являющимся генеральным директором компании «Армстронг Ворлд Индастриз», продвигающей потолочные и стеновые модульные системы под марками Knauf Ceiling Solutions и Armstrong.

Последний раз встреча в подобном формате проходила незадолго до пандемического локдауна. В этом году было принято решение в неформальной обстановке подвести итоги 2023 г., представить планы на 2024 г., обсудить тенденции рынка строительства и недвижимости, производство и сбыт строительных материалов и систем.

The construction of facilities for various purposes in rugged areas in cramped urban conditions for builders is the main problem associated with solving geotechnical tasks of providing both the slope itself and buildings and structures of the surrounding development in the zone of geotechnical influence. Questions arise regarding the need to develop buried retaining structures. The article considers a case from the geotechnical practice of installing retaining structures using bored piles with diameters of 600 mm and 800 mm and ground anchors arranged using electric discharge technology (ERT anchors).

Галина Ивановна Книгина, которой 14 марта 2024 г. исполнилось бы 115 лет, родилась в чудесном старинном городке на Волге – Юрьевце (Ивановская обл.), прославленном многими своими уроженцами. Город Юрьевец – город великой истории (в 2025 г. он отметит 800-летие!), культуры и творчества. Его уроженцами были братья Веснины – русские и советские архитекторы, знаменитый советский режиссер-сказочник А.А. Роу; великий советский режиссер А.А. Тарковский учился здесь в начальной школе, когда жил у бабушки, он называл город родиной детства. Город служил источником вдохновения для многих известных художников: виды Юрьевца запечатлены на картинах А.К. Саврасова, И.И. Левитана, Б.М. Кустодиева, Е.Е. Лансере, А.Н. Бенуа.

The determination of the surface free energy (SFE) is currently achieved using an instrumental method, one of which is «sessile drop». The surface free energy of quartz and caustic dolomite powders was defined before and after mechano-magnetic activation in the Vortex layer device. Free surface energy was identified by the well-known models proposed by the Owens–Wendt–Rabel–Kaelble (OWRK) and Van Oss–Chaudhury–Good (VOCG). The determination of the surface free energy (SFE) based on the presented model provides a good convergence: due to experimental assumptions, the deviation in calculation results is 14–16%. It was shown that mechano-magnetic treatment increased the adhesion of quartz powder by 86% (from 73 to 136 J/m²) and caustic dolomite by 217% (from 884 to 2800 J/m²). The mechano-magnetic treatment of study materials can significantly improve the interaction of the liquid with solid. This is evident from comparison of two attributes: the amount of change of specific interphase surface energy of a solid at the boundary with the gas per to change of specific surface of the powder and the change in the cosine of contact wetting angle per to a change in specific surface of the powder. This means the first value that represents the intensity of the interaction between liquids and solids multiplу greater than an integral characteristic of the interaction at the boundary of three phases. Such changes in geometric characteristics and surface properties are effective factors in structure formation control, especially hydration hardening.