Circular Building Research Articles

The transition towards a sustainable circular economy through life cycle assessment in the building and construction sector: a review and bibliometric analysis.

Transitioning to a circular economy is indispensable for the construction industry to achieve sustainable development goals. Understanding trends, gaps, and opportunities in life cycle assessment (LCA) for adopting a circular economy is critical. This study investigates the development of publications, identifies the most effective documents, authors, and countries, and highlights critical issues, knowledge axes, active research areas, and knowledge gaps. The study screened 196 out of 280 articles from the Scopus database and conducted a bibliometric analysis using CiteSpace and VOSviewer. Document clustering analysis identified the main research domains, and thematic classifications of knowledge areas and axes were provided. Additionally, development opportunities and knowledge gaps were identified through a full-text analysis of selected articles. The results show an increase in publications post-2017, with key research clusters including "Critical consideration," "Circular building component," "Building material," "Design for disassembly," "Integrated load match analysis," "Adaptive reuse project," "Data bank," "Prospective life cycle assessment," "Investment decision," and "Environmental comparison." Over 60% of the documents propose circular design solutions, end-of-life strategies, and alternative materials, while more than 80% focus solely on the environmental aspect. Only 4.6% develop integrated indicators, 2.5% automate LCA, 2.1% compile life cycle inventory databases, and 2% consider the social dimension. The findings emphasize the need to develop integrated indicators, methods, life cycle inventory databases, and automation tools based on integrated platforms and emerging technologies like building information modeling. This research identifies current knowledge gaps, suggests future research directions, and enhances understanding of how to make LCA more compatible with the circular economy.

Toward a collaborative circular ecosystem within the built environment

The built environment has drastically transitioned toward the circular economy (CE) to reduce carbon footprint, waste emission, and resource consumption. The circular ecosystem with close collaboration between diverse actors is critical to the sector's CE transition success. However, a holistic perspective on the circular ecosystem of the built environment remains lacking. This paper provides new insights into the complex and intricate dynamics of actor collaborations in the circular building ecosystems on the niche and regime levels. Moreover, this study shows the orchestrating roles of the municipalities and developers as the ‘keystone’ actors in the circular ecosystem. It also stresses the increasingly significant roles of new actors as the driving forces for the socio-technical paradigm shift toward CE in construction. The actor collaboration in the circular building ecosystem has been shifted to more collaborative and multi-dimensional (i.e., top-down, bottom-up, and horizontal). We also map the actor networks using CE principles and explain the importance of addressing incentives for stronger actor collaborations. Finally, this paper provides policy and managerial implications to reinforce collaboration dynamics and CE practices in the built environment.

Towards more circular building services: A social footprint of the sectors manufacturing and remanufacturing chillers for the European market

Towards more circular building services: A social footprint of the sectors manufacturing and remanufacturing chillers for the European market

Briefing for Circularity. Translating EU policies into operational guidelines for the building project

Abstract The current EU interest in Circular Economy offers novel opportunities to move towards more sustainable production and consumption practices. Literature confirms that building stakeholders are expressing a growing demand of common references and tools to support the integration of circular principles in building processes. The paper introduces a methodological approach meant as an information support tool to translate EU circularity policies into guidelines for building design and management. Indeed, the challenge is to translate circularity objectives and targets into specific requirements expressed from one stakeholder to another, up to the last operator involved in the supply chain. The requests along the different levels of the supply chain must be consistent with each other and with the initial circularity objectives expressed at the origin by the client. Hence, starting by outlining the complexity of the fragmented building supply-chain, the paper identifies the proper level of detail for expressing circularity requirements and, therefore, for communicating mutually consistent circularity objectives at the different levels of the supply chain. Supporting the integration of circularity requirements within Project Briefs (design phase) and Invitations to Tender (management phase), the proposed tool lays the foundations for the experimentation of circular building practices and for the systemic evaluation of compliance with EU circularity objectives.

Assessment methods and digital tools to support circular building strategies

Abstract The aim of the paper is to highlight how digital technology can be a vector for maintaining information of buildings products, promoting supply chain transparency and traceability of materials and environmental data, contributing to activate a sustainable circular economy. Indeed, the current lack of knowledge of product characteristics often hinders the activation of reverse logistic and the assessment of the environmental benefits of circular material flows. This means, on one hand, the need to trace and collect product characteristics and product environmental information throughout the entire life cycle, and, on the other hand, the to identify ways of communicating and sharing information. This paper outlines current digital tools to support transparency and traceability of materials. Next, the paper verticalises the method and indicators used to declare the circular and sustainable profile of products, emphasising the importance of applying Life Cycle Assessment (LCA). Finally, the prefiguration of a possible integration between traceability tools and the LCA methodology is discussed, identifying possible drivers (e.g. legislative, trainings) and possible key-operators for the widespread of the “LCA-integrated traceability tools”.

Additive manufacturing of interlocking glass masonry units

AbstractIn comparison to traditional glass casting, glass additive manufacturing (AM) presents an opportunity to increase design flexibility and reduce tooling costs for the production of highly variable geometries. While the latter has been extensively explored for masonry units, there is minimal research on the former for its viability to produce structural building components. This paper encompasses design, manufacturing, and experimental testing to assess the feasibility of using glass AM to produce interlocking masonry units for the construction industry. The glass 3D printer employed in this study is capable of printing a maximum volume of 32.5 $$\times $$ × 32.5 $$\times $$ × 38 cm–suitable for producing full-size masonry units. As part of this work, we discuss how to adapt design guidelines for glass AM to produce interlocking units. To evaluate fabrication ease and structural performance, three fabrication methods, Fully Hollow, Print-Cast, and Fully Printed, are compared. To compare the accuracy, repeatability, and structural capacity of each masonry unit, geometric analysis, surface roughness, and mechanical testing is conducted. Results varied by fabrication method, with average strength ranging from 3.64$$-$$ - 42.3 MPa for initial fracture and 64.0–118 MPa for ultimate strength. Accuracy in print dimensions was less than 1 mm with a standard deviation of 0.14–1.6 mm. Results demonstrated that Fully Hollow masonry units provide a more immediate path to implementation, while Fully Printed units have the potential to provide an entirely glass, transparent, and circular building component fabrication method.

Assessment of cantilevered curtain wall system supported by tension rods for an enclosed circular building

Curtain wall systems have undergone significant advancements to meet the evolving architectural requirements and achieve aesthetic appeal and functionality in buildings worldwide. These non-structural enclosures, typically constructed with lightweight materials like glass or metal panels, contribute to the visual appeal of high-rise structures while providing numerous benefits, such as ample natural light and unobstructed views. The current paper focuses on analyzing and designing a cantilevered curtain wall system supported by tension rods for the auditorium façade at a simulation centre. The curtain wall surrounds the entire primary structure of the building, which has a circular layout. The study uses numerical modeling with the Robot software to analyze stresses and deflections in the glass, tension rods, mullions, and transoms while considering a wind load of 1.6 kPa. According to the findings, tempered laminated glass that is 19.52 mm thick satisfies the Ultimate Limit States (ULS) and Serviceability Limit States (SLS). Under the limit states, the Technal system (FM169) reinforced with steel tubes can transfer the design loads. The steel framing system that supports the tension rods and transfers the load of the curtain wall to the main structure is likewise considered safe. The structural integrity of the curtain wall is ensured by the prescribed requirements for the connections, which include a 5 mm fillet weld with a throat thickness of 3.5 mm, 20 mm diameter tension rod (Kin long system), and 8 mm thick MS plates with channel brackets. This research expands the practical application of cantilevered curtain wall systems of buildings with enclosed circular layouts.

Advancing Circular Buildings: A Review of Building Strategies for AEC Stakeholders

The uptake of a circular economy (CE) in the building sector is challenging, primarily due to the complexity associated with the design process and the dynamic interaction among architects, engineers, and construction (AEC) stakeholders. The standard and typical design process and construction methods raise concerns about building life cycles. Buildings should not only fulfill current needs, but one also needs to consider how they will function in the future and throughout their lifetime. To address these complexities, early planning is required to guide designers in holistically applying systems thinking to deliver CE outcomes. This paper outlines a critical review of CE implementation in buildings, with a proposed trifecta of approaches that significantly contribute to the development of circular buildings (CBs). The findings outline a proposed visualized framework with a conceptual formula that integrates CE design strategies to simplify and enhance AEC stakeholders’ perception of the circularity sequence in buildings. By strategically integrating loop-based strategies with the value retention process (VRP) and design for X (DFX) strategies, along with efficient assessment tools and technologies, it becomes feasible to embrace a CE during the design phase. The outcome of this review informs AEC stakeholders to systematically and strategically integrate the critical dimensions of a CE throughout the building life cycle, striking a balance between environmental concern, economic value, and future needs.

Attaining material circularity in recycled construction waste to produce sustainable concrete blocks for residential building applications

Construction waste poses a major environmental problem owing to traditional building methods, resulting in a huge global waste burden that ultimately ends up in landfills. The development of sustainable methods is necessary not only to reduce environmental problems but also to encourage material circularity and promote the effective recycling and reuse of construction waste. Yet, previous research has largely focused on using recycled construction waste as a single or double additive ingredient. However, this study aims to assess the development of sustainable concrete blocks for residential building applications with a novel blend of two or more waste ingredients, with each additive contributing to a specific characteristic. Physical properties (bulk density, porosity, water absorption, thermal conductivity, compressive strength, fire resistance, and mass loss), cost, and CO2 emissions were determined to evaluate the efficiency of the block. Subsequently, the energy savings were assessed using block samples as single-layer building envelopes within a full-scale room simulated using EnergyPlus. The results showed a reduction in density of up to 24.32 %, and thermal conductivity and heat transfer of up to 56.8 % compared to typical blocks, which satisfied the compressive strength requirements of load- and non-load-bearing walls. The sustainability assessment revealed that the developed concrete blocks could significantly lower production costs by up to 31.75 % and reduce carbon emissions by up to 27.15 % compared to typical concrete blocks. It was found that the best single-layer building envelope in a full-scale residential room improved energy efficiency by up to 9.17 % when the produced blocks were used. This enhancement could lower the cost of energy consumption from 88.34 to 80.24 kWh/m2/year. This research contributes to the utilization of circular building blocks, which reduce the need for typical raw materials while improving their functional properties and lowering the production cost, carbon emissions, and energy consumption in a single-layer residential building.

Towards promoting circular building adaptability in adaptive reuse projects: a co-developed framework

Towards promoting circular building adaptability in adaptive reuse projects: a co-developed framework

Six Business Model Types for Circular Building Component Reuse Actors

While circular business models are receiving increasing academic attention, the business models of real circular building companies remain underexamined. This paper builds upon existing conceptual proposals and general overviews of reuse actors to investigate how these organizations capture and create value within the constraints of the marketplace. Using data from case studies of 25 organizations involved in the reuse of construction waste streams, the business model of each case is described and compared using Osterwalder and Pigneur’s Business Model Canvas. The authors propose six categories of circular construction business model types: upcyclers, component-specific suppliers, material resellers, reuse platforms, reuse consulting offices and deconstruction companies. The key findings include the studied organizations’ consolidation of multiple waste and new product streams, the strategic minimization of hard assets, the cultivation of diverse revenue streams and an emphasis on private market solutions.

Towards a Regenerative Design Project Delivery Workflow: A Critical Review

Regenerative design (RD) is an approach to creating positive change in the built environment rather than reducing its negative impacts. RD focuses its design work on improving the relationship between humans, places, and ecosystems. It also proposes fundamental paradigm shifts that promise to address the urgent climatic and biodiversity crises. While it presents a systemic, holistic method of understanding the place and the interrelationships between economic, social, and natural systems with a participatory and collaborative approach to design, its design methodology needs a detailed definition of tools to help new practitioners and students develop RD projects successfully and promote its widespread implementation. In particular, a general project delivery workflow is needed. This paper undertook a comprehensive review to fill this gap, examining 150 references, including articles, books, reports, and theses related to RD. It selected and analysed 19 sources from 1994 to 2024 to analyse and extract their content referencing project delivery steps. This paper proposes a novel six-step project delivery workflow and a workflow diagram that creatively synthesises the proposed RD project delivery workflow. These practical and applicable contributions are helpful for design and building practitioners willing to start a regenerative project. Additionally, this research found links and overlaps between RD and circular building (CB), suggesting opportunities for mutual further development of RD and CB.

Reviewing the critical factors for circular building design and construction

Reviewing the critical factors for circular building design and construction

The design and servitization of products according to the circular economy principles: An ecosystem perspective in the building industry

The transition from linear to circular economy is still far from being completed, particularly in the building industry. Indeed, its specific characteristics – such as the fragmentation of its business ecosystem – hinder the implementation of circular economy practices, and, particularly, circular product design and servitization practices. This paper analyses the collaborations among the companies involved in the design and servitization of one of the major elements of a building, the building façade, and it leverages on an action research methodology based on the “Envelope for Service” research project. The role of companies involved in the design and servitization of the circular building façade has been investigated. A novel research framework has been developed to match the circular practices implemented by the ecosystem of involved companies along the useful life phases of the building façade. The research framework highlights the paramount importance of collaborations within the business ecosystem of the building façade and shows how the interactions among companies take place and facilitate circular product design and servitization. We argue and provide evidence that the engagement of the whole business ecosystem is needed in fragmented industries, like the building industry, to implement circular product design and servitization practices. Finally, a hint of the relevance of digital technologies in enabling the implementation of circular practices in such industry is provided.

Cultural coherence of architecture in Greater Khorasan from Bactria to South Khorasan in Iran during the Late Iron Age/Achaemenid period

AbstractTappe Takhchar-Abad, near Birjand in south Khorasan, is a recently discovered and excavated almost circular adobe building with six towers, dating to the Achaemenid period. This article suggests that the architectural tradition of circular buildings and sites in the late Iron Age/Achaemenid period, in Greater Khorasan, apparently originated from Bactria in which most such sites have been reported.

The environmental impact of circular building design: A simplified approach to evaluate remountable building elements in life cycle assessment

Remountable building elements can be transformed according to our changing requirements, ensuring a long use of materials and buildings. To stimulate the implementation of remountable building elements, their environmental impact can be quantified through life cycle assessment (LCA). For a fair comparison between remountable and non-remountable building elements, transformations must be accounted for in LCAs. Yet, currently this is often not done. The purpose of this paper is to develop easy-to-use formulas to calculate the number of transformations and material replacements for remountable and non-remountable building elements. Different types of transformations are considered and it is analyzed how material replacements interact with transformations of the building element. The research is executed on two types of building elements: space dividing walls in offices and façade systems. The robustness of the developed formulas, further referred to as the simple formulas, is examined by comparing their results to those calculated by detailed formulas used in previous research, which determine the moment of occurrence of transformations and replacements. For each building element, the LCA results calculated by the simple and detailed approach are compared for numerous scenarios. In certain cases, the simple formulas over- or underestimate the number of replacements, but the majority of scenarios show limited differences. Furthermore, both approaches yield the same conclusions in a comparative LCA of the remountable and non-remountable space dividing wall. The simple formulas demonstrate how the calculation methods of LCA tools used in practice could be adapted to include the evaluation of remountable building elements.

Understanding the influence of ultrasonic power on the hydration of cement paste

This paper studied the dispersion and hydration of cement paste prepared by power ultrasound (PUS)-assisted mixing technology. The ultrasonic power used were 0 W, 480 W and 912 W. The hydration process and microstructure were tested by using isothermal calorimetry, X-ray diffraction (XRD), thermogravimetric-differential scanning calorimetry (TG-DSC), solid-state nuclear magnetic resonance silicon (29Si-NMR) spectroscopy, mercury intrusion porosimetry (MIP), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (SEM‒EDS). The results indicated that the dynamic hydration kinetics of cement paste under ultrasonic irradiation can be categorized into crystallization nucleation and growth (NG), phase boundary (I) and diffusion (D) processes. The apparent rate constant KNG in the NG process and KI in the I process both increased as the ultrasonic power increased, suggesting that PUS-assisted mixing accelerated the early hydration process. PUS shortened the dormant period and enhanced the total hydration heat release. The capillary pores and gel pores were both reduced at 28 days. Similarly, compared with those of C0 and C480, the gel porosities of C912 decreased by 35.17% and 31.87%, respectively. In addition, the mean chain length of the C–S–H gel increased with increasing ultrasonic power, which effectively filled the nanoscale defects. PUS improved the early strength and increased the strength at late hydration ages. Compared with that in the reference group, the compressive strength in the C912 group was enhanced by 26.1% at 1 day and 18.3% at 28 days. These findings demonstrate that power ultrasound-assisted mixing is advantageous for enhancing the sustainability of building materials, thereby contributing to the development of future circular buildings.

Circular building adaptability in multi-residential buildings – the status quo and a conceptual design framework

PurposeThere is a renowned interest in adaptability as an important principle for achieving circularity in the built environment. Circular building adaptability (CBA) could enable long-term building utilisation and flexible use of space with limited material flows. This paper identifies and analyses design strategies facilitating CBA to propose a framework for enhancing the implementation of the concept.Design/methodology/approachInterviews were conducted with professionals experienced in circular building design to explore the questions “How do currently applied design strategies enable CBA?” and “How can CBA be implemented through a conceptual design framework?”. The interviews encircled multi-residential building examples to identify currently applied circular design strategies. The interviews were analysed through qualitative content analysis using CBA determinants as a coding framework.FindingsThe results show that all ten CBA determinants are supported by design strategies applied in current circular building design. However, some determinants are more supported than others, and design strategies are often employed without explicitly considering adaptability. The design strategies that enable adaptability offer long-term solutions requiring large-scale modifications rather than facilitating low-impact adaptation by dwelling occupants. The proposed conceptual design framework could aid architects in resolving these issues and implementing CBA in their circular building design.Originality/valueThis paper’s contribution to CBA is threefold. It demonstrates design strategies facilitating CBA, proposes a conceptual design framework to apply the concept and identifies the need for a more comprehensive application of available adaptability strategies.

Life Cycle Assessment and Circular Building Design in South Asian Countries: A Review of the Current State of the Art and Research Potentials

A literature survey was proposed, aiming at summarizing the state of the art and, consequently, the research potential, in the increasingly popular field of circular economy, specifically applied to the construction industry in South Asian countries (Pakistan, India, and Bangladesh). In particular, the role of a life cycle assessment (LCA) to support the circular building design concept in construction projects was investigated. This review organized 71 published papers that examined environmental building assessments, certifications for sustainable buildings, the awareness of sustainable buildings, and recent advancements in this field between 2005 and 2022. The review pointed out that half of the LCA studies used the cradle-to-grave LCA methodology for environmental impact assessment, while the other half used the cradle-to-cradle LCA methodology. Regardless of the recent research, the literature still lacks the cradle-to-cradle implementation of the LCA methodology in selected countries which is essential for implementing truly circular building strategies. Moreover, the literature showed a lack of interest and awareness among all stakeholders in the construction of environmentally friendly buildings. The main barrier to carry out LCA for building performance is the unavailability of a regional database, which was pointed out in the literature, as well as the criteria for certification that are not available or do not comply with the standards of the specific contexts of Pakistan, India, and Bangladesh.

The optimized form of building made from the reused elements

ABSTRACT A resource-effective society considers a circular economy, and this attitude enters the construction industry as well. Various circular building approaches and strategies are introduced to promote a circular economy. However, the design process is complex because it evolves from available components. To address such a gap, in this article, we address design adjustments with the aim of maximizing the reusing of components from an architectural viewpoint, utilizing an applied research method. To achieve the goal, mathematical programming is suggested to make the best use of available components bearing a system approach in circular design in mind. The objective function is the allocation of reclaimed building materials and the decision variables are the needed components. The issue was categorized as integer nonlinear programming (INLP) solved for global optimality utilizing a genetic algorithm (GA). Design variants define different component allocations; thus, the optimum allocation defines the evolved design. Mathematical programming permits defining component allocation variants and the constraints associated with the project. The result of optimization defines the optimum allocation; consequently, it defines the evolved design. The presented procedure is an innovative method that aims to simplify the complexity associated with adjusting the design based on available components. It promotes procurement efficiency because it makes the best use of available material. Moreover, the minimum energy consumption for transportation due to local material usage leads to reuse efficiency.