Crystals

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19 pages, 3475 KiB

Open AccessArticle

Effect of Design Parameters on the Flexural Strength of Reinforced Concrete Sandwich Beams

by Vijayaprabha Chakrawarthi, Leon Raj Jesuarulraj, Siva Avudaiappan, Divya Rajendren, Mugahed Amran, Pablo Guindos, Krishanu Roy, Roman Fediuk and Nikolai Ivanovich Vatin

Crystals 2022, 12(8), 1021; https://doi.org/10.3390/cryst12081021 - 22 Jul 2022

Cited by 6 | Viewed by 1769

Abstract

Sandwich beams are preferable for aerostructure and marine structures due to their high mechanical strength, durability, stiffness, and fatigue resistance. This paper presents a study on the flexural behavior of sandwich beams made of self-compacting concrete comprising a polystyrene inner core with wire [...] Read more.

Sandwich beams are preferable for aerostructure and marine structures due to their high mechanical strength, durability, stiffness, and fatigue resistance. This paper presents a study on the flexural behavior of sandwich beams made of self-compacting concrete comprising a polystyrene inner core with wire mesh reinforcement. The effect of the design parameters such as the inner core area, percentage of tension reinforcement, and wire mesh on the moment carrying capacity and failure modes of sandwich beams was analyzed. Ten beams were cast and tested to failure with simply supported end conditions and they were classified into three different groups. The longitudinal section of the inner core area was varied by 0% (control beam), 25%, 50%, and 75% of the gross area. The tension reinforcement ratio varied between 0.6 and 1.5%. In addition, the effect of the wire mesh in shear and flexural resistance was studied. The load-carrying capacity of sandwich beams increased with flexural reinforcement. In addition, the welded wire mesh improved the sandwich beams’ flexural and shear performance. The conventional expressions for the moment of resistance were valid for sandwich beams, whereas the shear strength expressions overestimated the capacity; therefore, modifications were suggested. The refined models had a significant agreement with the experimental results. Full article

(This article belongs to the Special Issue Research of Construction and Building Materials in Peter the Great St. Petersburg Polytechnic University in Crystals)

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23 pages, 3978 KiB

Open AccessArticle

A Step towards Sustainable Concrete with Substitution of Plastic Waste in Concrete: Overview on Mechanical, Durability and Microstructure Analysis

by Jawad Ahmad, Ali Majdi, Ahmed Babeker Elhag, Ahmed Farouk Deifalla, Mahfooz Soomro, Haytham F. Isleem and Shaker Qaidi

Crystals 2022, 12(7), 944; https://doi.org/10.3390/cryst12070944 - 05 Jul 2022

Cited by 41 | Viewed by 5376

Abstract

Plastics have become an essential part of our daily lives, and global plastic production has increased dramatically in the past 50 years. This has significantly increased the amount of plastic garbage produced. Researchers have recently been interested in using trash and recyclable plastics [...] Read more.

Plastics have become an essential part of our daily lives, and global plastic production has increased dramatically in the past 50 years. This has significantly increased the amount of plastic garbage produced. Researchers have recently been interested in using trash and recyclable plastics in concrete as an ecologically acceptable building material. A large number of publications have been published that describe the behavior of concrete, containing waste and recovered plastic com ponents. However, information is scattered, and no one knows how plastic trash behaves as concrete materials. This research examines the use of plastic waste (PW) as aggregate or fiber in cement mortar and concrete manufacturing. The article reviewed the three most significant features of concrete: fresh properties, mechanical strength, and durability. PW and cement connections were also studied using microstructure analysis (scan electronic microscopy). The results showed that PW, as a fiber, enhanced mechanical performance, but PW, as a coarse aggregate, impaired concrete performance owing to poor bonding. The assessment also identified research needs in order to enhance the performance of PW-based concrete in the future. Full article

(This article belongs to the Special Issue Research of Construction and Building Materials in Peter the Great St. Petersburg Polytechnic University in Crystals)

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20 pages, 3922 KiB

Open AccessArticle

Foam Glass Crystalline Granular Material from a Polymineral Raw Mix

by Olga Miryuk, Roman Fediuk and Mugahed Amran

Crystals 2021, 11(12), 1447; https://doi.org/10.3390/cryst11121447 - 24 Nov 2021

Cited by 11 | Viewed by 2222

Abstract

The article is devoted to the development of resource-saving technology of porous granular materials for energy-efficient construction. The relevance of the work for international research is to emphasize expanding the raw material base of porous lightweight concrete aggregates at the expense of technogenic [...] Read more.

The article is devoted to the development of resource-saving technology of porous granular materials for energy-efficient construction. The relevance of the work for international research is to emphasize expanding the raw material base of porous lightweight concrete aggregates at the expense of technogenic and substandard materials. The work aims to study the processes of porization of glass crystalline granules from polymineral raw materials mixtures. The novelty of the work lies in the establishment of regularities of thermal foaming of glass crystalline granules when using waste of magnetic separation of skarn-magnetite (WMS) ores and lignite clay. Studies of liquid glass mixtures with various mineral fillers revealed the possibility of the formation of a porous structure with the participation of opoka, WMS and lignite clay. This is due to the presence in the materials of substances that exhibit thermal activity with the release of a gas phase. The foaming efficiency of the investigated materials increases when combined with glass breakage. The addition of WMS and lignite clay to the glass mixture increases the pore size in comparison with foam glass. The influence of the composition of raw mixtures on the molding and stability of granules is determined. The addition of sodium carbonate helps to strengthen the raw granules and reduce the softening temperature of the mass. The composition of the molding mixture of glass breakage, liquid glass and a multicomponent additive is developed, which provides an improvement in the molding properties of the glass mass, foaming of granules at a temperature of 750 °C. Foam glass crystalline granules have polymodal porosity, characterized by a density of 330–350 kg/m³, a compressive strength of 3.2–3.7 MPa, and a thermal conductivity of 0.057–0.061 W/(m·°C). Accordingly, the developed granules have a high potential use in structural and heat-insulating concretes. Full article

(This article belongs to the Special Issue Research of Construction and Building Materials in Peter the Great St. Petersburg Polytechnic University in Crystals)

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17 pages, 6983 KiB

Open AccessArticle

The Effect of Superabsorbent Polymer and Nano-Silica on the Properties of Blended Cement

by Renuka Senthil Muthalvan, Suraj Ravikumar, Siva Avudaiappan, Mugahed Amran, Radhamanohar Aepuru, Nikolai Vatin and Roman Fediuk

Crystals 2021, 11(11), 1394; https://doi.org/10.3390/cryst11111394 - 15 Nov 2021

Cited by 16 | Viewed by 2527

Abstract

Incorporating superabsorbent polymer (SAP), which has the abilities of absorption and desorption in cement mortar, can achieve the effect of internal curing. It is expected that the incorporation of nano-silica will improve the workability and strength in cement mortar/concrete. Hence, this study aims [...] Read more.

Incorporating superabsorbent polymer (SAP), which has the abilities of absorption and desorption in cement mortar, can achieve the effect of internal curing. It is expected that the incorporation of nano-silica will improve the workability and strength in cement mortar/concrete. Hence, this study aims to examine the effect of SAP and nano-silica on the properties of blended cement paste. The experimental investigations via several tests such as consistency, setting time, compressive strength, UPV, and acid test were performed. Based on energy-dispersive X-ray analysis (EDX) test and scanning electron microscopy (SEM) test results, the morphology of hydration products and mineral compositions of cement paste were further analysed, and the mechanism of SAP with 0.2% and 0.3% and NS with lower percentages ranging from 0.5% to 2% on the performance of cement paste was studied. The results exhibited that incorporating SAP in various percentages from 0.5% to 2% prolonged the initial setting time, reduced the fluidity, and increased the water content and formation of pores. In addition, various percentages ranging from 0.5% to 2% of NS were added; thereby, an increase in the hydration process and refining the microstructure was found. The microscopic test results showed that the blended cement paste can effectively improve the denser microstructure and refine the pore structure. Full article

(This article belongs to the Special Issue Research of Construction and Building Materials in Peter the Great St. Petersburg Polytechnic University in Crystals)

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17 pages, 5185 KiB

Open AccessArticle

Experimental Investigation and Image Processing to Predict the Properties of Concrete with the Addition of Nano Silica and Rice Husk Ash

by Siva Avudaiappan, Supriya Prakatanoju, Mugahed Amran, Radhamanohar Aepuru, Erick I. Saavedra Flores, Raj Das, Rishi Gupta, Roman Fediuk and Nikolai Vatin

Crystals 2021, 11(10), 1230; https://doi.org/10.3390/cryst11101230 - 12 Oct 2021

Cited by 24 | Viewed by 3141

Abstract

The use of the combination of ultrafine rice husk ash (RHA) and nano silica (NS) enhances the compactness of hardened concrete, but there is still a lack of studies that address the effects of NS and RHA on the workability, mechanical properties and [...] Read more.

The use of the combination of ultrafine rice husk ash (RHA) and nano silica (NS) enhances the compactness of hardened concrete, but there is still a lack of studies that address the effects of NS and RHA on the workability, mechanical properties and pore microstructure of concrete. This study mainly aims to investigate the influence of the pore size distribution in multiphysics concrete model modified by NS and RHA and to determine the workability and mechanical properties of concrete with NS and RHA. In this work, NS and RHA were used as 0, 5, 10, 15 and 20% replacements of ordinary Portland cement (OPC) in concrete grade M20. Concrete mixed with NS and RHA showed improved performance for up to 10% addition of NS and RHA. Further addition of NS and RHA showed a decrease in performance at 7, 14 and 28 days. The decrease in concrete porosity was also found to be up to 10% when adding NS and RHA to cement. Image processing was performed on the cement-based materials to describe the microstructure of the targeted material without damage. The results from the experimental and tomography images were utilized to investigate the concrete microstructure and predict its inner properties. Full article

(This article belongs to the Special Issue Research of Construction and Building Materials in Peter the Great St. Petersburg Polytechnic University in Crystals)

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16 pages, 3103 KiB

Open AccessArticle

Combined Effect of Multi-Walled Carbon Nanotubes, Steel Fibre and Glass Fibre Mesh on Novel Two-Stage Expanded Clay Aggregate Concrete against Impact Loading

by Gunasekaran Murali, Sallal R. Abid, Mugahed Amran, Roman Fediuk, Nikolai Vatin and Maria Karelina

Crystals 2021, 11(7), 720; https://doi.org/10.3390/cryst11070720 - 23 Jun 2021

Cited by 44 | Viewed by 4975

Abstract

The use of expanded clay aggregate (ECA) for developing lightweight concrete results in strength-reduction properties. However, the ECA-based concrete strength properties can be improved by adding steel fibre (SF), glass fibre mesh (GFM) and multi-walled nano-carbon tubes (MWCNT). The combined effect of MWCNT, [...] Read more.

The use of expanded clay aggregate (ECA) for developing lightweight concrete results in strength-reduction properties. However, the ECA-based concrete strength properties can be improved by adding steel fibre (SF), glass fibre mesh (GFM) and multi-walled nano-carbon tubes (MWCNT). The combined effect of MWCNT, GFM, SF and ECA-based concrete and its strength properties is still unexplored. It is worth drawing a logical conclusion concerning the impact on the strength of concrete by incorporating the materials mentioned above. Two-stage expanded clay aggregate fibrous concrete (TECAFC) is a new concrete type and an emerging research area in material engineering. The casting method of TECAFC includes the two essential phases as follows. First, ECA and fibres are filled into the empty cylindrical mould to develop a natural skeleton. Second, the grout comprising cement, sand and MWCNT, are injected into the developed skeleton to fill voids. In this research, eight mixtures were prepared with 0.1 and 0.2% of MWCNT, 2.5% dosage of SF and three different layers of GFM inserted between the two layers of concrete. These eight mixtures were divided into two series of three mixtures each, in addition to two reference mixtures that include no SF or GFM. The first series of mixtures was comprised of 0.1% of MWCNT and 2.5% of SF and one, two and three layers of GFM insertion. The second series was the same as the first series and the dosage of MWCNT was taken as 0.2%. All cylindrical specimens were tested under drop mass impact as per the suggestions made by the ACI Committee 544. The test results showed that incorporating steel fibres and GFM improved the cracking and failure impact resistance by more than 270 and 1100%, respectively, and increased the impact ductility index by more than 220%, significantly contributing to steel fibres. Full article

(This article belongs to the Special Issue Research of Construction and Building Materials in Peter the Great St. Petersburg Polytechnic University in Crystals)

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15 pages, 1961 KiB

Open AccessArticle

Thermal Performance of Structural Lightweight Concrete Composites for Potential Energy Saving

by Yeong Huei Lee, Nicholas Chua, Mugahed Amran, Yee Yong Lee, Ahmad Beng Hong Kueh, Roman Fediuk, Nikolai Vatin and Yuriy Vasilev

Crystals 2021, 11(5), 461; https://doi.org/10.3390/cryst11050461 - 21 Apr 2021

Cited by 28 | Viewed by 4539

Abstract

Residential consumption dominates the energy expenditure of heating and cooling systems, especially in tropical climates where building envelopes play an important role in energy efficiency. The thermal properties of concrete that are commonly employed as the building envelope material affect directly human comfort [...] Read more.

Residential consumption dominates the energy expenditure of heating and cooling systems, especially in tropical climates where building envelopes play an important role in energy efficiency. The thermal properties of concrete that are commonly employed as the building envelope material affect directly human comfort in a building. In addressing both the concrete thermal performance and industrial waste issues, this paper experimentally studies the concrete compressive strength and thermal properties used later for comparative energy analysis for human comfort. Four design mixes and a conventional concrete as control specimen are considered utilizing industrial wastes; palm oil fly ash (POFA), lightweight expanded clay aggregate (LECA), oil palm shell (OPS), and quarry dust, as constituents. These mixes are cast for cube compressive strength (to ensure the achievement of structural concrete requirement) and small-scaled wall tests. The measurement of surface temperatures of scaled wall tests is conducted in a polystyrene box to determine the concrete time lag and decrement factor. It is found that the density of concrete governs the compressive strength and that air pockets in the concrete matrix play an essential role as far as the thermal properties are concerned. From the energy analysis, structural lightweight concrete may save approximately 50% of the residential energy consumption. Full article

(This article belongs to the Special Issue Research of Construction and Building Materials in Peter the Great St. Petersburg Polytechnic University in Crystals)

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21 pages, 22801 KiB

Open AccessArticle

Increase the Performances of Lime Finishing Mixes Due to Modification with Calcium Silicate Hydrates

by Valentina Loganina, Kristina Sergeeva, Roman Fediuk, Valery Uvarov, Nikolai Vatin, Yuriy Vasilev, Mugahed Amran and Maciej Szelag

Crystals 2021, 11(4), 399; https://doi.org/10.3390/cryst11040399 - 09 Apr 2021

Cited by 11 | Viewed by 2285

Abstract

Lime plaster mixes are becoming more and more popular in the world’s building materials market every year. Therefore, the issue of increasing the efficiency of lime finishing coatings is relevant. The paper aim is the modification of lime binders with specially synthesized calcium [...] Read more.

Lime plaster mixes are becoming more and more popular in the world’s building materials market every year. Therefore, the issue of increasing the efficiency of lime finishing coatings is relevant. The paper aim is the modification of lime binders with specially synthesized calcium silicate hydrates (CSHs). To obtain the CSH filler, liquid sodium glass was used with a silicate module of 1.53–2.9 and a density of 1130–1663 kg/m³. Using differential thermal analysis (DTA), X-ray diffraction (XRD) patterns, synthesized calcium silicate hydrates, as well as dry plaster mixes, and finishing coatings based on using them were studied. The regularities of the filler synthesis were established depending on the temperature, density, and silicate modulus of liquid glass, the amount of the precipitant additive, the rate of its introduction, and the drying mode. As a result of processing the obtained experimental data, a mathematical model was obtained for the composition “lime + CSH”. The phase composition of the filler was revealed, which is characterized by the presence of calcium silicate hydrates of the tobermorite group, a solid solution CSH (B) in the form of a weakly crystallized gel, a solid solution of C–S–H (II), hydrohalites, and calcites. It was found that the use of the fillers into the lime compositions, obtained with the rapid introduction of CaCl₂ additive into water glass during the synthesis of the filler, promotes the acceleration of the plastic strength gain of lime compositions. It was revealed that the lime composites with the CSH filler are characterized by reduced shrinkage deformations up to 45%. The introduction of the CSH filler into the lime compositions increases the water resistance of the lime finishing layer by 36%. A technological scheme for the production of the lime dry plaster mixes has been developed; it can be introduced at existing factories of building materials without significant re-equipment of production. Full article

(This article belongs to the Special Issue Research of Construction and Building Materials in Peter the Great St. Petersburg Polytechnic University in Crystals)

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12 pages, 3533 KiB

Open AccessArticle

Granular Aggregates Based on Finely Dispersed Substandard Raw Materials

by Valery Lesovik, Liliya Zagorodnyuk, Vladislav Ryzhikh, Ruslan Lesovik, Roman Fediuk, Nikolai Vatin and Maria Karelina

Crystals 2021, 11(4), 369; https://doi.org/10.3390/cryst11040369 - 31 Mar 2021

Cited by 3 | Viewed by 1831

Abstract

It is necessary to solve the ecological problems of regions where there is large-tonnage storage of various finely dispersed materials, including technogenic ones. This article presents the results of an investigation into the possible use of substandard dispersed quartz sands to obtain effective [...] Read more.

It is necessary to solve the ecological problems of regions where there is large-tonnage storage of various finely dispersed materials, including technogenic ones. This article presents the results of an investigation into the possible use of substandard dispersed quartz sands to obtain effective granular aggregates, with the purpose of putting them to use in mortars and concrete. The study used standard and original experimental research methods related to the analysis and preparation of raw materials, technological tests, and the study of the properties of finished composites. Investigations were carried out to obtain composite binders in the component composition of which the use of different ratios of Portland cement and substandard quartz sands prepared in a vortex jet mill was envisaged. It was found that the obtained composite binders had high physical and mechanical characteristics, which was due to the high specific surface area and hydration activity. On the basis of composite binders and finely dispersed quartz sands (fineness from ≤0.16 mm to 1 mm), the granulation of mixtures of 36 types of component compositions was performed. The developed compositions of granular aggregates (GAs) showed the possibility of obtaining them with sufficiently high strength values in cement stone. The studies carried out make it possible to recommend finely dispersed substandard and technogenic materials for the production of GAs, which would ensure the economy of binding materials as well as contribute to the reuse of large-tonnage waste of ferrous and nonferrous metallurgy and the chemical and mining industries. Full article

(This article belongs to the Special Issue Research of Construction and Building Materials in Peter the Great St. Petersburg Polytechnic University in Crystals)

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11 pages, 2608 KiB

Open AccessArticle

Nano- and Micro-Modification of Building Reinforcing Bars of Various Types

by Aleksandr Rudenko, Alexander Biryukov, Oleg Kerzhentsev, Roman Fediuk, Nikolai Vatin, Yuriy Vasilev, Sergey Klyuev, Mugahed Amran and Maciej Szelag

Crystals 2021, 11(4), 323; https://doi.org/10.3390/cryst11040323 - 24 Mar 2021

Cited by 12 | Viewed by 2502

Abstract

Fiber-reinforced plastic (FRP) rebar has drawbacks that can limit its scope, such as poor heat resistance, decrease its strength over time, and under the influence of substances with an alkaline medium, as well as the drawback of a low modulus of elasticity and [...] Read more.

Fiber-reinforced plastic (FRP) rebar has drawbacks that can limit its scope, such as poor heat resistance, decrease its strength over time, and under the influence of substances with an alkaline medium, as well as the drawback of a low modulus of elasticity and deformation. Thus, the aim of the article is the nano- and micro-modification of building reinforcing bars using FRP rebars made of basalt fibers, which were impregnated with a thermosetting polymer binder with micro- or nanoparticles. The research discusses the major results of the developed composite reinforcement with the addition of micro- and nanosized particles. The microstructure of FRP has been studied using scanning electron microscopy. It was revealed that dispersion-strengthened polymer composites with the inclusion of microsilica (SiO₂) and nanosized aluminum oxide (Al₂O₃) particles have a much higher modulus of elasticity and strength when compared with the original polymer materials. In the course of the experiment, we also studied the retained plastic properties that are characterized by the absence of fragility. However, it was found that the high strength of materials was attained with a particle size of 10–500 nm, evenly distributed in the matrix, with an average distance between particles of 100–500 nm. It was also exhibited that composite reinforcement had improved the adhesion characteristics in comparison with both steel reinforcement (1.5–2 times, depending on the diameter), and with traditional unmodified FRP rebar (about 1.5 times). Thus, the use of micro-/nanosized powders increased the limit of the possible temperature range for the use and application of polymeric materials by almost two times, up to 286–320 °C, which will undoubtedly expand the range of the technological applications of products made of these materials. Full article

(This article belongs to the Special Issue Research of Construction and Building Materials in Peter the Great St. Petersburg Polytechnic University in Crystals)

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Review

Jump to: Research

25 pages, 2516 KiB

Open AccessReview

Concrete Reinforced with Sisal Fibers (SSF): Overview of Mechanical and Physical Properties

by Jawad Ahmad, Ali Majdi, Ahmed Farouk Deifalla, Nabil Ben Kahla and Mohammed A. El-Shorbagy

Crystals 2022, 12(7), 952; https://doi.org/10.3390/cryst12070952 - 07 Jul 2022

Cited by 25 | Viewed by 4728

Abstract

Concrete is a commonly used building material; however, it is subject to abrupt failure and limited energy absorption when yielding. The use of short discrete fibers has displayed a lot of potential in overcoming these issues. Sisal is a natural fiber that is [...] Read more.

Concrete is a commonly used building material; however, it is subject to abrupt failure and limited energy absorption when yielding. The use of short discrete fibers has displayed a lot of potential in overcoming these issues. Sisal is a natural fiber that is renewable, inexpensive, and readily accessible. SSF is a potential reinforcement for use in concrete because of its cheap cost, low density, high specific strength and modulus, negligible health risk, easy accessibility in certain states, and renewability. In current centuries, there has been growing importance in discovering new uses for SSF-reinforced concrete, which is normally utilized to make ropes, mats, carpets, and other decorative items. This article gives an overview of current advancements in SSF and composites. The qualities of SSF, the interface between SSF and the matrix, and SSF-reinforced properties such as fresh, mechanical strength, and durability have all been examined. The results show that SSF increased strength and durability while decreasing its flowability. The review also provides suggestions for further work. Full article

(This article belongs to the Special Issue Research of Construction and Building Materials in Peter the Great St. Petersburg Polytechnic University in Crystals)

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29 pages, 7087 KiB

Open AccessReview

Design Strategy for Recycled Aggregate Concrete: A Review of Status and Future Perspectives

by Natt Makul, Roman Fediuk, Mugahed Amran, Abdullah M. Zeyad, Sergey Klyuev, Irina Chulkova, Togay Ozbakkaloglu, Nikolai Vatin, Maria Karelina and Afonso Azevedo

Crystals 2021, 11(6), 695; https://doi.org/10.3390/cryst11060695 - 17 Jun 2021

Cited by 45 | Viewed by 5914

Abstract

Currently, a number of disadvantages hampers the use of recycled concrete aggregates (RCA). The current review proves that concretes made with complete replacement of natural aggregate with RCA allow the production of high-quality concrete. One of the possibilities for improving concrete properties with [...] Read more.

Currently, a number of disadvantages hampers the use of recycled concrete aggregates (RCA). The current review proves that concretes made with complete replacement of natural aggregate with RCA allow the production of high-quality concrete. One of the possibilities for improving concrete properties with RCA is the use of extended curing and pozzolanic materials with varying cement ratios. The potential use of RCA concretes is in the production of high-value materials that increase environmental and financial benefits. RCA have strong potential in the development of a new generation of concrete and stimulate economic activity in many countries in addition to optimizing natural resources. Economic benefits include minimal travel costs; cheaper sources of concrete than newly mined aggregates; reduction of the landfill area required for the placement of concrete waste; the use of RCA minimizes the need for gravel extraction, etc. The proposed strategy could be to sequentially separate demolition waste such as roof finishes, waterproof materials, interior and exterior materials, etc. Closing life cycles is the main approach used for efficient structures for the recycling and reuse of construction and demolition waste in the production and recovery of materials, especially when recycling and reusing materials. In the life cycle, the recycling of recovered materials allows them to be used for new construction purposes, avoiding the use of natural concrete aggregates. Government, design institutes, construction departments and project managers should be involved in the creation and use of RCA. In demolition and construction, the main players are the project owners. Their obligations, expectations and responsibilities must be properly aligned. For the past 20 years, recycled concrete aggregate from demolition and construction waste has been considered as an alternative to pure concrete in structural concrete to minimize the environmental impact of construction waste and demolition waste and the conversion of natural aggregate resources. It is now recognized that the use of RCA for the generations of concrete is a promising and very attractive technology for reducing the environmental impact of the construction sector and conserving natural resources. In the market, the selling price is not an obstacle for market applications of RCA, as there are scenarios in which their cost is lower than the cost of products made from conventional building materials. This is more of an acceptance factor in the market for recycled concrete aggregates. In this sector, the lack of identification, accreditation and uniform quality certification systems and their narrow application cause some marketing problems. With proper RCA preparation, concrete with standard physical and mechanical properties and performance characteristics can be obtained. Full article

(This article belongs to the Special Issue Research of Construction and Building Materials in Peter the Great St. Petersburg Polytechnic University in Crystals)

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