Recycling

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17 pages, 3806 KiB

Open AccessArticle

Quantifying Recycled Construction and Demolition Waste for Use in 3D-Printed Concrete

by Wibke De Villiers, Mwiti Mwongo, Adewumi John Babafemi and Gideon Van Zijl

Recycling 2024, 9(4), 55; https://doi.org/10.3390/recycling9040055 - 28 Jun 2024

Cited by 1 | Viewed by 1596

Abstract

Despite extensive regulations, the systemic under-reporting of construction and demolition waste generation rates pervades the South African waste sector due to the extensive and active informal waste management practices that are typical of developing countries. This study merges the rapid development of high-technology [...] Read more.

Despite extensive regulations, the systemic under-reporting of construction and demolition waste generation rates pervades the South African waste sector due to the extensive and active informal waste management practices that are typical of developing countries. This study merges the rapid development of high-technology 3D-printed concrete (3DPC) with the increasing pressure that the built environment is placing on both natural resource consumption and landfill space due to construction and demolition waste (CDW) by establishing an inventory of CDW that is suitable for use in 3DPC in South Africa. This is an essential step in ensuring the technical, economic, and logistical viability of using CDW as aggregate or supplementary cementitious materials in 3DPC. Of the methods considered, the lifetime material analysis and per capita multiplier methods are the most appropriate for the context and available seed data; this results in CDW estimates of 24.3 Mt and 12.2 Mt per annum in South Africa, respectively. This range is due to the different points of estimation for the two methods considered, and the per capita multiplier method provides an inevitable underestimation. In order to contextualise the estimated availability of CDW material for use in concrete in general, the demand for coarse and fine aggregate and supplementary cementitious material in South Africa is quantified as 77.9 Mt. This overall annual demand far exceeds the estimated CDW material (12.2–24.3 Mt) available as an alternative material source for concrete. Full article

(This article belongs to the Special Issue Sustainable Management in Eco-Materials, Industrial Residues and Construction and Demolition Waste)

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12 pages, 2851 KiB

Open AccessArticle

Study of the Mechanical and Electrochemical Performance of Structural Concrete Incorporating Recycled Polyethylene Terephthalate as a Partial Fine Aggregate Replacement

by Ana Cecilia Espindola-Flores, Michelle Alejandra Luna-Jimenez, Edgar Onofre-Bustamante and Ana Beatriz Morales-Cepeda

Recycling 2024, 9(3), 51; https://doi.org/10.3390/recycling9030051 - 20 Jun 2024

Viewed by 1282

Abstract

The extraction of materials, such as sand and gravel, required for the manufacture of concrete results in the overexploitation of natural resources and a large release of CO₂ emissions into the environment. Therefore, the search for alternatives to partially replace these aggregates [...] Read more.

The extraction of materials, such as sand and gravel, required for the manufacture of concrete results in the overexploitation of natural resources and a large release of CO₂ emissions into the environment. Therefore, the search for alternatives to partially replace these aggregates has become an important issue to solve. Nonetheless, the demand for producing sustainable yet high-strength and durable concrete using alternative materials has led concrete technologists to develop high-performance concrete. These novel concretes possess superior engineering properties, such as high durability and ductility, low maintenance costs, high mechanical strength, and prolonged service life. Currently, there is significant interest in the development of concrete–polymer compounds, primarily to improve the mechanical properties of the material. In this context, the present study explores the partial replacement of fine aggregate with recycled Polyethylene terephthalate (R-PET) in different proportions to produce green structural concrete, with the aim of studying its impact on the mechanical and electrochemical properties. The mechanical properties evaluated were the compressive and flexural strengths, while the electrochemical properties were evaluated through the open circuit potential and polarization curves. The results indicated that specimens containing different R-PET percentages as a replacement for fine aggregate showed higher increases in compressive and flexural strengths. It was also found that the presence of R-PET decreased the corrosion rate of the reinforcing steel when seawater was used as the electrolyte. Full article

(This article belongs to the Special Issue Sustainable Management in Eco-Materials, Industrial Residues and Construction and Demolition Waste)

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29 pages, 8910 KiB

Open AccessArticle

Effect of Recycled Concrete Aggregate Addition on the Asphalt Mixtures Performance: ITZ Area, Microstructure, and Chemical Analysis Perspectives

by Hanaa Khaleel Alwan Al-Bayati, Waleed Jadaa and Susan L. Tighe

Recycling 2024, 9(3), 41; https://doi.org/10.3390/recycling9030041 - 18 May 2024

Viewed by 1483

Abstract

The importance of environmental consciousness and sustainability is increasing among transportation governing bodies worldwide. Many government bodies are concerned with maximizing the usage of recycled substances in road construction. Therefore, assessing the effect of recycled materials consumption is essential, mainly when designing new [...] Read more.

The importance of environmental consciousness and sustainability is increasing among transportation governing bodies worldwide. Many government bodies are concerned with maximizing the usage of recycled substances in road construction. Therefore, assessing the effect of recycled materials consumption is essential, mainly when designing new ‘green’ pavement types. The primary objective of this study is to investigate the impact of different treatments on improving the interfacial transition zone (ITZ) of coarse recycled concrete aggregate (CRCA) and its application in asphalt mixes. Such an aim is accomplished by enhancing its physical and mechanical characteristics, as well as its microstructure. The surface morphology, chemical composition, and intermix phases of the ITZ area and calcium silicate hydrate (CSH) compounds for CRCA were evaluated using scanning electron microscopy (SEM), an energy-dispersive X-ray analyzer (EDAX), and X-ray diffraction analysis (XRD). The performance of asphalt mixtures that included treated and untreated CRCA was also examined using different tests. It was found that heat treatment is an effective technique for enhancing the ITZ. However, cracks were seen in the mortar of CRCA when exposed to high temperatures (500 °C), which adversely affects the characteristics of the mortar. Acid treatment appeared to be an effective approach for improving the ITZ area. Nevertheless, the treatment that used acetic acid, a weak acid, was more effective than HCl acid, a strong acid. The outcomes revealed that the ITZ microstructure is significantly enhanced under different treatment types; however, microstructure improvements mainly included increased surface homogeneity and CSH compounds and a reduced Ca/Si ratio. It was also found that the asphalt mixtures with different proportions of untreated CRCA exhibited enhanced resistance to rutting. Furthermore, their tensile strength ratio (TSR) values were above the minimal level requirements. Moreover, the asphalt mixture with 30% CRCA, which was treated with various treatment methods, demonstrated a significant improvement in the mixtures’ mechanical properties; therefore, its application is highly successful and an environmentally friendly solution. Full article

(This article belongs to the Special Issue Sustainable Management in Eco-Materials, Industrial Residues and Construction and Demolition Waste)

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20 pages, 5661 KiB

Open AccessArticle

A Sustainable Solution with Improved Chemical Resilience Using Repurposed Glass Fibers for Sewage Rehabilitation Pipes

by Devanand Chelot, Shivnarain Ravichandran and Priyank Upadhyaya

Recycling 2024, 9(2), 28; https://doi.org/10.3390/recycling9020028 - 31 Mar 2024

Viewed by 1709

Abstract

This paper introduces a sustainable sewage rehabilitation solution, utilizing repurposed glass fibers for enhanced chemical resilience and environmental conservation. The approach involves dividing a unitary pipe into segments, assembled during commissioning, aiming to reduce installation and transportation costs, particularly in less accessible areas. [...] Read more.

This paper introduces a sustainable sewage rehabilitation solution, utilizing repurposed glass fibers for enhanced chemical resilience and environmental conservation. The approach involves dividing a unitary pipe into segments, assembled during commissioning, aiming to reduce installation and transportation costs, particularly in less accessible areas. Each pipe segment comprises a multi-layered glass fiber composite sandwich, joined by an adhesive reinforced with recycled glass fibers. The glass fiber-reinforced plastic (GFRP) pipe features a core of blended sand impregnated with resin, an outer layer for impact resistance, and an inner layer to prevent corrosion. Chemical resilience is assessed through a 10,000 h strain corrosion study exposing both unitary and two-piece circular GFRP pipes to sulfuric acid in a deflected condition. An apparent hoop tensile test evaluates mechanical integrity before and after exposure. The experimental results reveal that the two-piece pipe with a tongue and groove joint (TGJ) with recycled glass fiber adhesive exhibits superior long-term bending stress and failure strain % compared to unitary pipes. This enhancement is attributed to the TGJ’s improved load-bearing capability and chemical resistance. The failure strain % of the two-piece pipe (1.697%) is higher compared to the unitary pipe (1.2613%). The long-term bending stress of the two-piece pipe obtained is 119.94 MPa whereas the unitary pipe reaches 93.48 MPa at the 50-year mark. The cost analysis supports the adoption of the two-piece pipe over unitary pipes due to a 40% reduction in carbon emissions and transportation cost. The novelty lies in the utilization of multi-piece pipes with enhanced chemical resilience, achieved through the incorporation of milled fiberglass reinforcements in the TGJ. Strain corrosion tests take a long time to perform; hence, an accelerated test is needed to improve the current recommended testing standard. Full article

(This article belongs to the Special Issue Sustainable Management in Eco-Materials, Industrial Residues and Construction and Demolition Waste)

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18 pages, 7788 KiB

Open AccessArticle

Non-Structural Vibro-Compressed Concrete Incorporating Industrial Wastes

by Gabriela Bertazzi Pignotti, Ana Mafalda Matos and Fernanda Giannotti da Silva Ferreira

Recycling 2024, 9(2), 26; https://doi.org/10.3390/recycling9020026 - 25 Mar 2024

Cited by 1 | Viewed by 1729

Abstract

This study presents more eco-efficient concrete formulations for precast vibro-compressed masonry blocks. The proposed formulations incorporated industrial waste, glass powder (GP), and quartz powder (QP), in which natural aggregate was partially replaced by QP (10%) and Portland cement by GP (10% and 20%). [...] Read more.

This study presents more eco-efficient concrete formulations for precast vibro-compressed masonry blocks. The proposed formulations incorporated industrial waste, glass powder (GP), and quartz powder (QP), in which natural aggregate was partially replaced by QP (10%) and Portland cement by GP (10% and 20%). The best combination of powder materials, water, and admixture was optimised at mortar level, considering a “zero slump” criteria and compressive strength. Afterwards, studies at concrete level followed. Specimens were vibrated and compressed in laboratory and immediately demoulded, aiming to simulate the industrial process. The compressive strength decreased when GP and QP were used alone; however, when combining 10% GP as cement replacement + 10% QP as fine aggregate replacement, the compressive strength increased by approximately 26.6% compared to the reference concrete. Water absorption results varied between 8.92 and 17.9%, and the lowest absorption was obtained by concrete specimens incorporating 20% GP. The UPV presented a narrow range of variation among all concrete mixtures under study, around 2–2.5 km/s at 28 days, whereas electrical resistivity was achieved at 28 days, at 20,000 and 25,000 ohms. Although there were some limitations of the casting process at the laboratory scale, the research results showed promising results, and it seems feasible to use this waste as a substitute for non-renewable raw materials in the production of concrete on an industrial scale. This can provide added value to abundant local wastes while contributing to a circular concrete economy. Full article

(This article belongs to the Special Issue Sustainable Management in Eco-Materials, Industrial Residues and Construction and Demolition Waste)

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11 pages, 1440 KiB

Open AccessArticle

Reforming Construction Waste Management for Circular Economy in Kazakhstan: A Cost–Benefit Analysis of Upgrading Construction and Demolition Waste Recycling Centres

by Ferhat Karaca and Aidana Tleuken

Recycling 2024, 9(1), 2; https://doi.org/10.3390/recycling9010002 - 29 Dec 2023

Viewed by 2913

Abstract

This paper investigates the advantages of enhancing construction and demolition waste (CDW) recycling facilities to conform to circular economy (CE) models in Kazakhstan’s construction sector. The industry is experiencing significant growth due to urbanization, but it faces difficulties managing CDW, frequently resulting in [...] Read more.

This paper investigates the advantages of enhancing construction and demolition waste (CDW) recycling facilities to conform to circular economy (CE) models in Kazakhstan’s construction sector. The industry is experiencing significant growth due to urbanization, but it faces difficulties managing CDW, frequently resulting in landfill disposal. In response, this paper provides a cost–benefit analysis of upgrading the CDW recycling centres aligned with CE needs. Reflecting legislative changes in Kazakhstan’s Environmental Code, which prohibited CDW in landfills starting December 2020, the initiative to establish modern CDW recycling centres is gaining momentum in major cities. The primary objective is to maximize material recovery and eliminate contaminants that curtail the utilization of recycled sand and aggregate products. The analysis yields compelling results, indicating that the project has the potential to recycle up to 84 million tons of CDW over eight years, with an annual 25% capacity increase and a maximum possible 95% recycling efficiency. Despite an estimated cost of USD 48 million, the project demonstrates a payback period of 9.9 years, signalling eventual cost recovery. These findings underscore the project’s capacity to mitigate CDW issues while generating economic benefits and contributing to a sustainable environment. In conclusion, implementing modern CDW recycling centres in Kazakhstan represents a potent solution for the construction industry as it transitions toward a CE model. This transition addresses both pressing environmental challenges and promising economic prospects. Full article

(This article belongs to the Special Issue Sustainable Management in Eco-Materials, Industrial Residues and Construction and Demolition Waste)

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12 pages, 4173 KiB

Open AccessArticle

Properties of High-Flowability Liquefied Stabilized Soil Made of Recycled Construction Sludge

by Yuji Shigematsu, Shinya Inazumi, Susit Chaiprakaikeow and Supakij Nontananandh

Recycling 2023, 8(5), 67; https://doi.org/10.3390/recycling8050067 - 30 Aug 2023

Cited by 3 | Viewed by 2714

Abstract

This paper focuses on the development of high-flowability liquefied stabilized soils (HFLSS) made of recycled construction sludge (RCS) to enhance their application in construction work. Liquefied stabilized soils (LSSs) have already found widespread use in construction sites, particularly for filling long-distance structures and [...] Read more.

This paper focuses on the development of high-flowability liquefied stabilized soils (HFLSS) made of recycled construction sludge (RCS) to enhance their application in construction work. Liquefied stabilized soils (LSSs) have already found widespread use in construction sites, particularly for filling long-distance structures and dealing with complex underground spaces. However, to further optimize their performance, the development of high-flowability liquefied stabilized soils (HFLSSs) with superior flowability is required. This study experimentally investigates the basic properties, including mechanical characteristics and flowability performance, of the newly developed HFLSS made of RCS. The results confirm that the developed HFLSS made of RCS meets the quality requirements expected from LSSs and exhibits enhanced flowability, making it a promising material for construction applications. The advanced development of LSSs in this paper expects to promote recycling construction-generated soils, including construction-generated sludges in the construction industry. Full article

(This article belongs to the Special Issue Sustainable Management in Eco-Materials, Industrial Residues and Construction and Demolition Waste)

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Review

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24 pages, 14429 KiB

Open AccessReview

Circularity Outlines in the Construction and Demolition Waste Management: A Literature Review

by Izabella-Eva Gherman, Elena-Simina Lakatos, Sorin Dan Clinci, Florin Lungu, Vladut Vasile Constandoiu, Lucian Ionel Cioca and Elena Cristina Rada

Recycling 2023, 8(5), 69; https://doi.org/10.3390/recycling8050069 - 11 Sep 2023

Cited by 9 | Viewed by 8337

Abstract

This study provides a comprehensive view of the research field of construction and demolition waste (CDW) management in the circular economy based on a literature review. The increased intensity of interest is due to the need to create frameworks, mechanisms, and tools for [...] Read more.

This study provides a comprehensive view of the research field of construction and demolition waste (CDW) management in the circular economy based on a literature review. The increased intensity of interest is due to the need to create frameworks, mechanisms, and tools for the process of mind-shifting towards circularity. Research topics, researched life cycle stages, strategies for CDW management, sustainability assessment, building stock quantification, assessment tools and forecast methods, materials with CDW content, waste treatment solutions, and the barriers and drivers for efficient waste management in the construction industry are identified as the main concerns in the analyzed research field. The results show that a major concern in the academic field directs research to the path of innovative strategy elaboration, identifying the enablers and barriers in CDW management, computational tool creation for design and assessment, building stock modeling, and circular building material development. The environmental approach prevails, leaving economic and social assessments in CDW management uncovered. Although stakeholders’ involvement is stressed in most cases, strategies for awareness-raising and education for a sustainable circular activity in the field are lacking. The circularity of CDW management being a multifaceted and multi-disciplinary complex challenge, it is approached on different levels. This study introduces the novelty of structuring the trends of existing knowledge in a holistic view, identifying the research directions, dimensions, specific aspects, and instruments. Full article

(This article belongs to the Special Issue Sustainable Management in Eco-Materials, Industrial Residues and Construction and Demolition Waste)

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