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This paper aims to explore UAE's transition towards circular economy (CE) through construction and demolition waste (CDW) management in the pre-construction stage. The extent of circularity is assessed by five key aspects of CE, such as policies and strategic frameworks, design for waste prevention, design for disassembly or deconstruction, use of prefabricated elements and CDW management plans.

Multiple case studies were conducted in the context of the Dubai construction industry (UAE). Three significant and unique construction projects were selected as the cases. Semi-structured interviews were carried out to collect data, and the thematic analysis technique and NVIVO 12 software were used for data analysis.

Findings reveal several positive initiatives towards CE in the UAE context; yet it is identified that the transition is still at the initial stage. Selected case studies, the best-case scenarios of UAE (i.e. influential cases), demonstrated adequate measures in relation to four key CE aspects out of five. For instance, (a) policies and strategic frameworks such as lean standards, green building standards and standards developed by the local authorities, (b) design for waste prevention (e.g. adherence to the 3R principle, and construction planning with BIM), (c) use of prefabricated elements and application of innovative construction technologies (e.g. 3DPC, DfMA) and (d) CDW management planning such as 3R principle were evident. However, the selected cases hardly showcase designing for disassembly or deconstruction.

The existing CDW practices are mostly conventional, as most constructions in UAE are procured through conventional building materials and methods. Therefore, there is a necessity of encouraging CE principles in CDW management. Even though the transition towards CE was evident in four key CE aspects out of five, the UAE construction industry has yet to adopt more effective CE-based CDW management practices to accelerate the circularity. Hence, it is necessary to enforce standard waste management guidelines, including the 3R principle, to standardise CDW management in UAE and encourage construction practitioners to adhere to CE principles.

The findings of this study provide valuable insights for decision-making processes around CDW management towards a CE. This paper contributes to the literature by bridging the CE concept with CDW management in the pre-construction stage. The study provides insights for industry practitioners for planning CE in terms of policies and strategic frameworks, CDW management planning, construction planning and application of innovative construction technologies.

Construction and Demolition (C&D) Waste Management (WM) poses significant challenges in Sri Lanka, contributing to environmental degradation and resource depletion. To address these issues, this study explores the application of Circular Economy (CE) strategies in minimising waste generation and optimising resource utilisation in Sri Lankan construction industry. The research focuses on the construction and building renovation and use and operate stages of the building project life cycle, recognising their significance in waste generation and resource consumption.

The research employed a qualitative approach, utilising the Delphi technique through three rounds of expert interviews. Seventeen experts were involved in the first round, followed by fifteen in the second round, and twelve in the final round. The collected data was analysed using manual content analysis methods.

The research findings revealed fifteen C&D WM issues in the construction and building renovation stage in Sri Lanka, along with suitable strategies to overcome each of them. Similarly, eight C&D WM issues were identified for the use and operate stage of the building, and corresponding strategies were provided to address each issue. By adopting CE strategies such as modular design and material reuse, construction projects can optimise the project's timeline, cost, and quality factors. These strategies enable efficient resource allocation, reduce waste generation, and contribute to the overall sustainability of the project. The impact of CE strategies on mitigating these issues within the project management iron triangle was also discussed.

This paper entails delving into how construction, building renovation, and operation stages of a building's life cycle intersect with CE strategies, which profoundly influence operational efficiency and long-term sustainability. By incorporating principles such as energy efficiency, water conservation, and circular product design, the paper illuminates how these strategies facilitate decreased energy usage, enhanced resource management, and diminished waste production throughout the building's lifespan.

The preferences and adoption of recycled materials by consumers are subject to a variety of factors, such as enablers and barriers. Despite this, there exists a paucity of research concerning stakeholders' perceived value and real purchase decision towards recycled products. Consequently, this research study aims to fill this gap by investigating stakeholders' perceived value of recycled products derived from construction and demolition (C&D) waste and its effect on purchase decisions.

Research data were collected from 219 valid questionnaires completed by Chinese stakeholders. Structural equation modeling (SEM) was then employed to test eight hypotheses.

The results show intrinsic cue (materials) and extrinsic cue (brand) influence the stakeholders’ judgment on C&D waste recycled products’ value and then their purchase intention. However, cues such as quality, word-of-mouth, price, policy and advertised have not play a significant role in practice.

This research study verified the significance of brand and material cues on decision making for purchasing C&D waste recycled products, providing new insights to policy making to enhance the uptake of C&D waste recycled products in construction industry.

The utilisation of products with recycled content (PwRC) in construction projects has been identified as a targeted way to achieve sustainable management of construction and demolition waste resources. However, sustainable applications of these resources are subject to a wide array of factors that demand a thorough investigation. This study, therefore, explores the motivations, barriers and strategies for optimal PwRC uptake using a multiple-case study approach.

This study adopted an interpretive multiple-case study approach. The case studies were selected from recently completed construction projects including two infrastructure projects, one commercial project and one residential project. A series of semi-structured interviews were carried out to collect the data. For each case study, four participants were interviewed; these participants represented design, client, supply and building teams.

The study revealed the main barriers, motivations and opportunities for adoption of PwRC resources in four construction projects. These factors are believed to influence the utilisation of PwRC to varying extents and/or in diverse ways. The findings also suggest that there is a significant opportunity for stakeholders to adopt more sustainable waste management practices, and the use of institutional drivers can help achieve this goal.

The primary research contribution of the study lies in proposing three key research directions: investigating regulatory constraints impacting the use of PwRC, addressing supply chain challenges and enhancing quality assurance.

The research has a practical contribution to the industry through a suite of actionable strategies to increase the uptake of PwRC. The strategies are mostly focussed on stakeholders' education, the regulation that supports PwRC and project management planning. The two major motivations – referring to two of the three pillars of sustainability (economy and environment) – provide a basis for organisational changes to ensure achieving sustainability in construction activities.

This review paper, using a systematic literature review (SLR) approach, aims to unravel the various system-wide waste in the construction industry and highlight the connectivity to construction phases, namely men, materials, machines, methods and measurement (5M) and impacting factors.

This study used an SLR approach and examined articles published since the 2000s to explore the connectivity of system-wide waste to construction phases, 5M and impacting factors. The results are given in table forms and a causal loop diagram.

Results show that the construction and demolition (CD) waste research carried out from various perspectives is standalone. The review identified ten types of system-wide waste with strong interlinks in the construction industry. The finding highlights connectivity between wastes other than material, labour and time and the wastes' impacting factors. Further, the review results highlighted the solid connectivity for construction phases, 5M, and impacting factors such as productivity (P), delay (D), accidents (A), resource utilisation (R) and cost(C).

SLR methodology limitations include not keeping in phase with the most updated field knowledge. This limitation is offset by choosing the range for literature review within the last two decades. This literature review may not have captured all published articles because the restriction of database access and search was based only on English. Also, fruitful articles hiding in less popular journals may not be included in the well-known database that was searched. Researcher bias of the authors and other researchers that authored the articles referred to is a limitation. These limitations are acknowledged.

This article unravels the construction system-wide waste and the waste's interlinks, which would aid industry understanding and focus on eliminating the waste. The article highlights the connectivity of system-wide wastes to 5M, which would help better understand the causes of the waste. Further, the paper discusses the connectivity of system-wide waste, 5M and P, D, A, R and C that would aid the organisation's overall performance. The practical and theoretical implications include a better understanding of waste types to help capture better data for waste reduction and productivity improvement. The operating managers could use the tracking of wastes to compare estimated and actual resources at every process stage. This article on system-wide waste, 5M and P, D, A, R and C, relationships and their effects can theorize that the construction industry is more likely to identify clear root causes of waste now than previously. The theoretical implications include enhanced understanding for academics on connectivity between waste, 5M and P, D, A, R and C that the academics can use and expand to provide new insights to existing knowledge.

For the first time, this article categorised and highlighted the ten types of waste in construction industries and the industries' connectivity to construction phases, 5M and impacting factors.

The circular economy business models (CEBMs) provide ways for firms operating in the construction industry to move from a linear to a circular approach. Thus, this study aims to explore CEBM research within the construction sector to show the focus area of studies, highlighting new areas that require attention.

This study adopted a bibliometric approach, using the Scopus database as the data source. The keywords used for paper extraction from the database were “circular economy business” OR “circular business” AND “model” OR “models” AND “construction industry” OR “building industry”. The VOSviewer software was then used to prepare a co-occurrence and co-authorship map based on the bibliographic data gathered.

The study’s findings reveal five research clusters in the construction industry. These clusters include circular construction intelligence, modular business modelling, eco-construction, sustainable construction economics and smart energy-efficient buildings. The two most cited scholars had two publications each, while the top journals are the Journal of Cleaner Production and Sustainable Production and Consumption. This study concludes that there is a need for research within the construction sector to focus on CEBMs’ archetypes and frameworks. This will enable a smooth transition from linear to circular business models in the sector.

The information was gathered from a single database, Scopus; hence, using other databases, including Web of Science, Google Scholar and Dimensions, might produce more articles for examination and, consequently, different findings on the subject under investigation.

These findings would assist researchers in considering the areas mentioned, which are yet to receive attention, and, by extension, enhance economic development while maintaining environmental sustainability.

This paper made a significant contribution to the body of knowledge by identifying scholars and platforms that have been instrumental in advancing CEBM research and highlighting new areas that require attention in the construction sector.

The application of circular economy (CE) has received wide coverage in the built environment, including public-private partnership (PPP) infrastructure projects, in recent times. However, current studies and practical implementation of CE are largely associated with construction demolition, waste and recycling management. Few studies exist on circular models and success factors of public infrastructures developed within the PPP contracts. Thus, the main objective of this article is to identify the models and key success factors associated with CE implementation in PPP infrastructure projects.

A systematic review of the literature was undertaken in this study using forty-two (42) peer-reviewed journal articles from Scopus, Web of Science, Google Scholar and PubMed.

The results show that environmental factors, sustainable economic growth, effective stakeholder management, sufficient funding, utilization of low-carbon materials, effective supply chain and procurement strategies facilitate the implementation of CE in PPP infrastructure projects. Key CE business models are centered around the extension of project life cycle value, circular inputs and recycling and reuse of projects.

Although the study presents relevant findings and gaps for further investigations, it has a limited sample size of 42 papers, which is expected to increase as CE gain more prominence in PPP infrastructure management in future.

The findings are relevant for decision-making by PPP practitioners to attain the social, economic and environmental benefits of transitioning to circular infrastructure management.

This study contributes to articulating the key models and measures toward sustainable CE in public infrastructure development.

This study aims to identify in literature the role of construction stakeholders in the implementation of circular economy (CE) in the construction industry (CI). This study also sought to identify the status quo and research trend, “hot themes”, areas requiring more research and future research direction of stakeholders’ role in CE implementation in the CI.

A literature search was conducted using the Scopus search engine, augmented by Google Scholar to produce 50 relevant articles for the identification of stakeholders’ roles using content analysis. The scientometric study was undertaken using VOSviewer on 42 articles obtained from Scopus search to identify the status quo, “hot themes”, knowledge gaps and future research direction of the role of stakeholders in CE implementation.

Through content analysis, the identified roles of government as a stakeholder are to develop efficient policy instruments, legislation support and financial investment in research and development activities that will promote the smooth implementation of CE. The role of academia/research is to engage in research aimed at investigating both the short-term behaviour and the durability of recycled materials and products. In addition, the roles of professionals in the consultant/design/procurement team are to design with life cycle assessment and reused materials, design for deconstruction and disassembly, etc. The role of the user/consumer is to ensure knowledge diffusion and awareness exchange that recognize the available opportunities for long-term material usage (including repair, reuse, refurbishment and recycling). The research status quo identified from the scientometric analysis include how stakeholders can come up with innovative ways in demolition that will ensure that more of the materials can be reused. Stakeholders should focus on enacting policies and laws that can promote the use of recycled materials in buildings, etc. Research that focuses on how to engage the various construction stakeholders to come up with specific public policy that will promote CE implementation, identifying the specific roles to be played by stakeholders during policy enactment as well as managing the environment, laws and legislations towards CE implementation. The role of stakeholders in the extension of the life span of projects, the use of strategies to minimize waste generation and standardization of building materials, components and connectors with the purpose of simplifying disassembly are the research gaps and areas for future research studies. Some of the research “hot themes” include “circular business models in the CI”, “environmental sustainability policy implementation”, “environmental, economic and social sustainability”, “policy, laws and legislations on waste management” and “environmental and industrial economics” towards CE implementation.

The findings from this study serve as a valuable reference for construction stakeholders to assess their specific roles as stakeholders and to identify the status quo and research trend, “hot themes”, areas requiring more research and future research directions on stakeholders’ roles in CE implementation in the CI.

Identifying the role of stakeholders for CE implementation is one bold step towards the achievement of CE implementation in the CI.

The purpose of this study is to assess the potential benefits of digital technologies (DTs) in bolstering the circular economy (CE) transition in the construction industry, to speed up the attainment of sustainable development objectives.

A detailed literature review was undertaken to identify DTs that could influence CE transition and the benefits of these DTs in the CE transitioning efforts of the construction industry. Based on these, a survey questionnaire was formulated and administered to construction professionals using convenient sampling techniques. With a response rate of 49.42% and data reliability of over 0.800, the gathered data were analysed using frequency and percentage, mean item score, normalisation value, coefficient of variation, Kendall’s coefficient of concordance, analysis of variance and factor analysis.

This study found that the construction experts agreed that building information modelling, blockchain technology, RFID, drone technology and cloud computing are the leading DTs that have the potential to influence and speed up CE transition in construction. Also, six clusters of benefits of DTs in bolstering EC are quicken CE transition, proactive waste management, recycling and zero waste, data management and decision-making, enhance productivity and performance and resource optimisation.

Studies on the integration of DTs in CE transition are scarce and it is even lacking in the Nigerian context. To the best of the authors’ knowledge, this study is the first to assess the role of DTs in CE transitioning in the Nigerian construction industry.

Concrete, the second most used material in the world, surpassed only by water, relies on a vast amount of cement. The process of cement production emits substantial amounts of carbon dioxide (CO₂). Consequently, it is crucial to search for cement alternatives. Geopolymer concrete (GC) uses industrial by-product material instead of traditional cement, which not only reduces CO₂ emissions but also enhances concrete durability. On the other hand, the disposal of concrete waste in the landfills represents a significant environmental challenge, emphasising the urgent need for sustainable solutions. This study aimed to investigate waste concrete's best form and rate as the alternative aggregates in self-compacting and ambient-cured GC to preserve natural resources, reduce construction and demolition waste and decrease pertinent CO₂ emissions. The binding material employed in this research encompasses fly ash, slag, micro fly ash and anhydrous sodium metasilicate as an alkali activator. It also introduces the best treatment method to improve the recycled concrete aggregate (RCA) quality.

A total of25%, 50% and 100% of coarse aggregates are replaced with RCAs to cast self-compacting geopolymer concrete (SCGC) and assess the impact of RCA on the fresh, hardened and water absorption properties of the ambient-cured GC. Geopolymer slurry was used for coating RCAs and the authors examined the effect of one-day and seven-day cured coated RCA. The mechanical properties (compressive strength, splitting tensile strength and modulus of elasticity), rheological properties (slump flow, T500 and J-ring) and total water absorption of RCA-based SCGC were studied. The microstructural and chemical compositions of the concrete mixes were studied by the methods of energy dispersive X-Ray and scanning electron microscopy.

It is evident from the test observations that 100% replacement of natural aggregate with coated RCA using geopolymer slurry containing fly ash, slag, micro fly ash and anhydrous sodium metasilicate cured for one day before mixing enhances the concrete's quality and complies with the flowability requirements. Assessment is based on the fresh and hardened properties of the SCGC with various RCA contents and coating periods. The fresh properties of the mix with a seven-day curing time for coated RCA did not meet the requirements for self-compacting concrete, while this mix demonstrated better compressive strength (31.61 MPa) and modulus of elasticity (15.39 GPa) compared to 29.36 MPa and 9.8 GPa, respectively, for the mix with one-day cured coated RCA. However, incorporating one-day-cured coated RCA in SCGC demonstrated better splitting tensile strength (2.32 MPa) and water absorption (15.16%).

A potential limitation of this study on SCGC with coated RCAs is the focus on the short-term behaviour of this concrete. This limited time frame may not meet the long-term requirements for ensuring the sustained durability of the structures throughout their service life.

This paper highlights the treatment technique of coating RCA with geopolymer slurry for casting SCGC.