Vol. 6 Issue 2

Archives Journal Construction Materials and Products 2023

Experimental studies of the processes of structure formation of composite mixtures with technogenic mechanoactivated silica component

https://doi.org/10.58224/2618-7183-2023-6-2-5-18
Abstract
The paper considers the issues of utilization of technogenic fibrous material – waste of basalt production. The chemical composition of the technogenic fibrous material was studied, it was found that it consists of 44% SiO2. The initial basalt rock, which undergoes changes during high-temperature processing in the process of obtaining basalt fiber, was studied using IR spectroscopy. The grinding of the crowns was carried out for 30 minutes, allowing to reach a specific surface area of 800 m2 / kg. Further grinding does not lead to an increase in the specific surface area, which is associated with the phenomenon of secondary aggregation of fine particles. Research on REM has shown that the “cold shots” before grinding are mostly rounded or oval in shape. The compositions were formed and the strength characteristics of the samples for the 3rd and 28th day were determined. The maximum strength gain of 59 MPa was established at the age of 28 days in samples with the addition of 5% ground “cold shots” . When introducing cold shots in an amount of 10% (composition 5) of the cement mass, an intensive strength gain is noted in the early stages of hardening (7 days) with a strength of 38 MPa, slightly higher than the strength of the control composition. The introduction of 15% ground “cold shots” gives a strength value slightly lower (32 MPa) than the values of the control composition (37 MPa) at all stages of hardening.
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Efficient Silicate Composites of Dense Structure using hollow microspheres and Unconventional Aluminosilicate Raw Materials

https://doi.org/10.58224/2618-7183-2023-6-2-19-34
Abstract
One of the urgent tasks in the field of building materials science is to provide the construction complex with various types of environmentally friendly, reliable and energy-saving materials, the production and use of which will contribute to solving the problem of anthropogenic impact on the environment through the use of little-used technogenic raw materials. In the current conditions of import substitution, it is necessary to use the existing technological base to increase the volume of production of affordable, highly efficient, environmentally friendly traditional building materials, including using the existing raw materials base of the regions. In the market of building materials, structural wall materials of hydration hardening obtained using Portland cement as a binder are widely represented. However, silicate materials occupy not a small market share. It is known that pressed silicate materials of dense structure have fairly good strength indicators, but their thermophysical characteristics are low. A decrease in the average density of dense silicate products can be achieved by introducing various pore-forming components, such as hollow microspheres, into the raw material mass. The paper shows that the use of hollow aluminosilicate microspheres in the technology of obtaining silicate materials of dense structure based on unconventional aluminosilicate raw materials with energy-saving parameters of autoclave synthesis (water vapor pressure 0.4 MPa) and under conditions of heat and humidity treatment at atmospheric pressure allows to obtain a building composite with improved thermophysical and acoustic properties. Introduction to the raw mixture of aluminosilicate microspheres in the amount of 10-60 wt. % allows you to reduce the value of the average density index to 45%. The value of the compressive strength index of such samples, depending on the composition and hardening conditions, is 7-21.5 MPa at their average density of 920-1610 kg /m3, respectively.
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Influence of dynamic loads on fatigue strength of steel beams reinforced with carbon fiber

https://doi.org/10.58224/2618-7183-2023-6-2-35-46
Abstract
The paper evaluates the strength and fatigue characteristics of reinforced damaged steel beams using composite materials – fiber reinforced polymers (FRP) using an analytical model using the ANSYS program. An approach to design based on the methodology of a constant fatigue schedule is considered; models of five steel beams reinforced with carbon fiber are constructed in the ANSYS program. The model was loaded with a symmetrically located concentrated load until destruction. Fa-tigue crack propagation curves have shown that carbon fiber plates restrain crack growth and increase durability. The results showed that carbon fiber reinforcement of steel beams increases the ultimate load and increases the plasticity of the beam.
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Bridge construction in cramped urban environments

https://doi.org/10.58224/2618-7183-2023-6-2-47-57
Abstract
This article discusses the specifics of the construction of bridge structures in cramped conditions of dense urban development. The classification of bridge structures and features of each type are given. The main characteristics and weight and size parameters of elements of bridge structures, methods of their erection, transportation and installation are considered. Particular attention is paid to the arrangement of the construction site, transportation of finished products and materials to the construc-tion site, as well as measures to prevent damage to buildings, structures and transport routes adjacent to the construction site, including the railway.
The study considered the project for the implementation of the construction of the Strela overpass in the city of Tyumen. Emphasis was placed on the production of radial prestressed reinforced con-crete beams of span structures in construction conditions. It was decided to manufacture these struc-tures at the work site.
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Magnetic iron oxide nanoparticles: synthesis, surface modification, and functionalization by luminescent materials

https://doi.org/10.58224/2618-7183-2023-6-2-58-80
Abstract
From the standpoint of current science and engineering, iron oxide particles exhibit remarkable physical and structural features, particularly in the nanoscale range. Several methods have been studied to fabricate magnetic iron oxide nanoparticles and determine how they affect the size, size distribution, elemental composition, crystal structure, and a variety of other physical properties of nanoparticles. Advances in surface chemistry strategies for the functionalization of iron oxide-based magnetic nanoparticles (IONPs) are also explained. This review aims to present a summary of emerging activity relating to composite magneto-fluorescent nano-objects. Due to the high surface energies of iron oxide nanoparticles, agglomeration over time is often encountered. It is thus of prime importance to modify their surface to prevent aggregation and limit non-specific adsorption of fluorescent molecules onto it. Furthermore, the diverse strategies for the covalent linking with fluorescent organic dyes have been discussed, and the chemically relevant steps have been explained in detail. Surface coating and functionalization of iron oxide NPs allow them to attach to fluorescent molecules and prevent photoluminescence quenching entities by the magnetic core, making them a promising candidate for nondestructive magnetic inspections based on nanoparticles.
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Prerequisites and Trends in the Architecture of Modern Circuses

https://doi.org/10.58224/2618-7183-2023-6-2-81-103
Abstract
The article considers the prerequisites for the emergence and development of circuses typology, from street circuses, arenas, then tent constructions of circuses-chapitos to the formation of a stationary circus building. The periods of circuses' existence in Europe as well as in domestic practice are studied. Circus buildings in different periods, their formation, architectural appearance and the functional content of the planning solutions are discussed. In the process of writing the article different methods were used for the study and analysis: a comprehensive analysis of the design materials, photofixation, review of professional literature and publications. The objects of foreign practice, the Soviet and Russian design experience were chosen for the analysis. On the basis of this study the following conclusions were obtained. In Europe and in Russia existing circuses are reconstructed. There is no new permanent circuses being built in Europe, unlike Russia, where the continuation of the Nikitin circus traditions is traced both in circus art and in the architecture of the permanent circus. The circus is losing the niche of performing with animals, where they remain in the circus, and control over their housing, housing, and transportation is becoming stricter. There is a tendency to build multifunctional public entertainment buildings with elements of circus performances. There are still circus circuses, and in the future they will either be stationary circuses on tour, or a new kind of circus circus similar to Cirque du Soleil.
A modern circus is a multifunctional, unique architectural object, a spectacular building, which combines circus art and various show performances (on ice, on water, in the air). The central core re-mains the main arena. Currently it is a round arena, but it may be reconstructed in the future. Circus is a cultural and historical heritage in Russia.
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Method for calculating the strength of massive structural elements in the general case of their stress-strain state (parametric equations of the strength surface)

https://doi.org/10.58224/2618-7183-2023-6-2-104-120
Abstract
In the mechanics of a deformable solid, there are rods (one overall dimension of which is significantly larger than the other two), plates and shells (one dimension of which is significantly smaller than the other two), arrays (all three dimensions of which are of the same order). The complexity of the corresponding calculation models grows in the same order: the calculation models for rods and rod systems are relatively simple, the most complex are the calculation models for massive structural elements.
In the work, parametric equations of the strength surface in the space of internal force factors (IFF) are obtained – 9 forces and 9 moments for homogeneous anisotropic bodies. As special cases, similar equations are given for isotropic bodies that resist tension and compression differently, for isotropic bodies that equally resist tension and compression. Algorithm A1 for constructing the desired sections of strength surfaces given by parametric equations is proposed. Algorithm A2 is proposed for deter-mining the safety factors for the bearing capacity, remaining in the space of the IFF. Some examples of calculations made using the proposed equations, algorithms and the corresponding computer programs compiled on their basis are given.
The proposed method for calculating massive bodies allows a more realistic assessment of the bearing capacity of massive structural elements.
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