Circular Construction Research Articles

In-ground and above-ground service life prediction for timber reusability - Progressing towards circular construction

The increasing demand for and consumption of wood requires special attention in order to keep the wood industry sustainable. Therefore, timber reuse is presented as a solution to control the demand side. Unfortunately, the perception of timber decay poses a major barrier for reuse practices. Therefore, this article presents a factorised service life prediction model for wooden components that aims to promote their reuse. The model is based on the Australian service life prediction model, Timberlife, and the European CLICKdesign model's dose-response model. It predicts the potential for reuse of timber components based on their expected and remaining service life. To determine the service life, the model includes factors that differentiate between wood species, soil characteristics, regional climate and how the investigated components are connected to other components. The presented model focuses on in-ground and above-ground fungal decay and is limited to northwestern Europe. Opportunities for further research include, e.g., a further investigation of the soil characteristics' influence on decay, and evaluating the lag time for regions outside northwestern Europe. The presented service life prediction model can increase awareness and support a circular construction industry.

The Potential Contribution of Modular Volumetric Timber Buildings to Circular Construction: A State-of-the-Art Review Based on Literature and 60 Case Studies

When facing the increasing demands of the housing market and balancing the requirements of sustainable development in the construction sector, building design methods should practise material conservation and adopt carbon reduction measures to alleviate the current environmental burden through the implementation of a circular economy approach. Volumetric modular timber design is recognised as a practical application to test the feasibility of a waste-reduced approach. Driven by the aim of further improving volumetric modular timber construction and increasing its use in a circular economy framework, this paper presents a case study review of 60 modular timber building projects constructed using volumetric modules. The dimensions, the architectural and structural design, and the manufacturing and assembly processes of the three-dimensional modular units were assessed to explore their potential for contributing to a circular built environment. The results show that the similarly sized modular volumetric timber units have the potential to serve different functions, and to be reused in subsequent projects. The stacking design allows modular volumetric units to be reused in a way that supports function conversion and satisfies project coordination criteria. The case studies illustrate that modular timber buildings are increasingly used for flexible design solutions, and to meet carbon emission reduction targets. The analysis results can address prevalent misconceptions regarding modular wood construction, provide interested parties with a better understanding, and promote the use of modular volumetric timber units in general.

Integrating bottom-up building stock model with logistics networks to support the site selection of circular construction hub

The circular construction hub is a logistics point for the storage, processing, and distribution of secondary construction materials. However, its site selection is dampened by the lack of detailed spatial information on material flows. In this study, the quantities and the spatial distribution of material flows are projected using a bottom-up building stock model. The material flows are integrated with logistics networks to assess the environmental impact of transporting materials between the building stock and the circular construction hub. The model is demonstrated on the building stock of Leiden, a municipality in the Netherlands. The results show that the location of future construction and demolition activities has a major impact on transportation carbon emissions. As construction decreases and demolition increases, the relative share of transportation carbon emissions from recycling will increase. The comparison between the two candidate sites for the circular construction hub is made to select the site with lower total transportation carbon emissions. By considering the evolution of building stock, the model can help urban planners make a more comprehensive decision on the location of the circular construction hub.

Understanding the key risks in circular construction projects: from systematic review to conceptual framework

Purpose Circular construction offers sustainable solutions and opportunities to disentangle a project’s life cycle, including demolition, deconstruction and repurposing of architectural, civil engineering and infrastructure projects from the extraction of natural resources and their wasteful usage. However, it introduces additional layers of novel risks and uncertainties in the delivery of projects. The purpose of this study is to review the relevant literature to discover, classify and theorize the critical risk factors for circular construction projects. Design/methodology/approach The paper conducted a systematic literature review to investigate the risks of circular construction projects. It deployed a multistage approach, including literature search and assessment, metadata extraction, citation frequency analysis, Pareto analysis and total interpretive structural modeling. Findings Sixty-eight critical risk factors were identified and categorized into nine broad taxonomies: material risks, organizational risks, supply chain risks, technological risks, financial risks, design risks, health and safety risks, regulatory risks and stakeholder risks. Using the Pareto analysis, a conceptual map of 47 key critical risk factors was generated for circular construction projects. A hierarchical model was further developed to hypothesize the multiple possible connections and interdependencies of the taxonomies, leading to chain reactions and push effects of the key risks impacting circular construction projects. Originality/value This study constitutes the first systematic review of the literature, consolidating and theorizing the chain reactions of the critical risk factors for circular construction projects. Thus, it provides a better understanding of risks in circular construction projects.

Integration of BIM and design for deconstruction to improve circular economy of buildings

Faced with the environmental impacts caused by civil construction, including the large consumption of resources and waste generation, the reuse of materials and construction elements in project's early stage is considered as a possible solution in this research, which draws on theoretical reference of Open Building and Circular Economy. In this way, integrated to these approaches, the concept of Design for Deconstruction (DfD) for the design of buildings addresses the elaboration of the project with the final objective of dismantling buildings, in a partial or total way, allowing and increasing material recycling and mainly the reuse of constructive elements in the circular construction chain. However, despite the knowledge developed about DfD, the application of this concept is still incipient and the deconstruction practice remains unsatisfactory and still can be improved in many ways. The operationalization DfD in a BIM environment has the benefit of supporting the design process and subsequent deconstruction management. In this regard, the aim of this study is to propose a solution to expand the practice of deconstruction through the use of a BIM tool in buildings design, implemented in Autodesk Revit using Dynamo. To validate the artefact, a case study was conducted.

Human energy. An anthropological perspective on labour and skills in circular construction

The circulation of used building components is performed through human labour such as assessment, logistics, design, and (de-)construction. This paper analyses different kinds of human energy employed in the process of moving building components from demolition to construction sites for reuse. Based on ethnographic data from Switzerland, Italy, and Austria, we qualitatively assess human energy and labour at different stages of circular construction. Through the use of human skills and knowledge, energy is mobilised to evaluate, document, dismantle, design, store, transport, and construct with materials. Our anthropological approach focuses on people and services instead of treating materials and technologies as independent from the workforce handling them. The results underline the complexity and diversity of opinions regarding the value of labour in relation to overall project costs.

Circular construction: Six key recommendations

Circular construction: Six key recommendations

Circular Practices in Construction

The construction sector creates exorbitant amounts of emissions and waste. Adressing a livable future, we argue for a radical shift in the way we think, design, and use buildings. Therefore, we present findings of our ongoing research project Circular Material Systems (CMS) that contributes to an understanding of buildings as circular systems that produce reusable components or biodegradable materials by practices operating across a building’s lifecycle. The main question of this paper is: How to translate the Circular Economy (CE) concept for construction? The findings are based on in-depth case studies of 25 buildings across Europe. We use the notion of ‘practices’ to both enrich the academic debate on circular construction and create a best-practice collection for practitioners. The proposed framework includes strategies and practices that address the construction sector’s urgent need to reduce its environmental impact. We connected these strategies to the 9R framework to illustrate the harmonisation with the CE concept. What we found particularly interesting is that there are repeating patterns of practices applied in the analysed buildings while working with local materials, knowing and redesigning supply chains as well as collaboration models to involve a wide variety of necessary actors are characteristic practices for achieving circularity. To advance the paradigm of circular construction, every stakeholder in the building process is required to look beyond their responsibilities to find new innovative solutions for circularity while further research should focus on implementation pathways as well as legal and enabling factors.

Evaluation of the properties of a new circular building composite material to upcycle building wastes

A new circular composite material for building applications is developed, made of two secondary raw materials coming from waste recycling: fibers and sand. Hydraulic lime is added as a binder. This new composite targets a low environmental impact thanks to benefits of upcycling buildings waste, low energy production process, lifetime up to 60 years and of a high potential of reversibility, reuse and upcycling. The research focused on mechanical and physical properties, as well as analysis of the microstructure by X-ray 3D microtomography and in-situ compression testing. The mechanical and physical test results show good and unexpected properties: a density of 390 to 1300 kg/m3; a compressive strength between 0.2 and 2.2 MPa, a bending strength of 0.1 to 1.9 MPa and a thermal conductivity of 0.06 to 0.14 W/mK. Further research will focus on circular construction and environmental aspects. Three applications are envisioned, according the standards of the building sector.

A paradigm shift in designing circular steel buildings: Some key principles and pioneering projects

AbstractThe building and construction sector is responsible for approximately 40 % of global carbon emissions, and if improvement is not made in the short term, this impact will probably double in the next 20 years. Recently, the European Green Deal set a target of achieving net‐zero greenhouse gas emissions by 2050, for which the construction industry will need to apply drastic measures given the significance of its impact on the global emissions. Efficient ways of proceeding in that direction, allowing to quantify and effectively reduce the carbon emissions of buildings and infrastructures, rely on life‐cycle assessments (LCA) and circularity concepts. Applying the latter in practice requires a paradigm shift, which is necessary to implement in the earliest stages of a construction project if an effective, robust and realistic result is targeted. This article covers some key principles which can be kept in mind for the preparation of a circular construction project, as well as some pioneering projects in Europe which highlight a real possibility of delivering circular steel buildings.

Quantification and specification of agricultural by-products as local resources for mycelium-bound composites

The research focuses on Upstate New York and quantifies the available agricultural wastes and by-products to identify their application as substrates for mycelium-bound composites (hereinafter MBC) functioning as nutrient, aggregate, and reinforcement in the production of local biological building materials. The literature review indicates that the biggest contributor to the mechanical strength of MBC is the substrate’s ability to support strong and dense mycelial growth. To estimate the locally available agricultural wastes in the Finger Lakes region of New York, yield data, residue-to-grain ratio, moisture content, and weight are used to determine the dry tons of residue produced in 2021 in New York. Reports suggest that agricultural residues, particularly corn stover, are widespread and underutilized in the United States, representing a major potential resource. This research explores the potential of using corn stover, especially cobs as a material resource for new circular construction paradigms in the Finger Lakes region’s circular economy. Further research aims to increase control of growth parameters and material specification in the production of local biological building materials.

Circular building design: a case study in Pakistan

A major transformation from the current, linear practice to a closed-loop system, linked with a circular economy, is required to transform the negative effects of buildings on the environment. Pakistan has one of the fastest growing populations, and conventional building construction is increasing in urban areas due to urban sprawl. This research aims to demonstrate the possible shift to a circular construction industry in Pakistan by comparing the linear design components with the circular design components of exterior walls of a case study taking advantage of life cycle assessment. The results of life cycle assessment applied to the external walls of a house in Karachi show that finding the solution with the lowest impacts is not obvious and that use of apparently “green” solutions may turn out to have higher impacts. Study suggests that building components can be gradually replaced with more circular ones to create a circular built environment.

Circular construction with AAC—recycling of an industrial hall made of Hebel elements in Munich‐Puchheim

AbstractIn Germany, construction, and demolition waste accounts for more than half of the waste generated, which means that valuable raw materials are lost for high‐quality recycling. But there is a solution: switching to a closed material cycle in which discarded products are reprocessed so that they can be used to manufacture the original or at least an equivalent product. A pilot project near Munich in Germany is demonstrating how discarded Xella products can be recycled into new products of equal value—with pioneering results. An old industrial hall made of prefabricated Hebel AAC‐wall elements was demolished, the material collected and processed into AAC powder, which was subjected to the production of new AAC. In the meantime, a new hall made of AAC has been built on the same site.

Towards a complex push-to-pull dynamics in circular construction supply chains: a systematic literature review

PurposeThe development of circular construction supply chains (CCSCs) is impeded by various barriers, but the current literature overlooks the interrelationships among these barriers and the varying nature of associated countermeasures with the growth of circular economy (CE). This paper aims to develop new perspectives about the transition to CCSCs through the lens of supply-push (SP)/demand-pull (DP) strategies and related underpinning theories.Design/methodology/approachA systematic literature review including 136 journal articles was undertaken to identify barriers to CCSCs and associated countermeasures that are analysed for their relevance to SP/DP. The interplay between SP/DP approaches was discussed using the “technology acceptance” and “innovation chain” models.Findings(1) Thirty-five barriers were identified and organised into nine main barrier factors; (2) the predominant factors are knowledge and awareness, policy and regulations, technological capabilities, and incentives; (3) CCSCs transition is SP-configured primarily driven by actors above the project network; (4) “push” measures are devised to gradually create a “pull” environment and can be revoked when demand for circularity is created, suggesting a new “push-to-pull” perspective of CCSCs; and (5) a complex adaptative system is witnessed in relationships between barriers and countermeasures, and interactions among actors at all levels.Practical implicationsThe findings offer practitioners countermeasures to barriers encountered in CE initiatives. It also informs policymakers of adjusting policies to accommodate the SP-DP movement in steering the circular transition.Originality/valueThis study uses theoretical models to interpret the dynamics in CCSCs transition and proposes a new definition of CCSCs highlighting their complex and dual transitional/transformational nature.

Effect of Crushing Method on the Properties of Produced Recycled Concrete Aggregates

Construction and Demolition Waste (C&DW) is generated around the world and its quantity will increase in the future. Recycling has become the favored method of dealing with concrete waste but, to avoid its downcycling, it is important to develop a recycling process which is able to produce high-grade recycled concrete aggregates (RCA). To that end, studying the influence of the production process on the properties of RCA can prove to be a crucial step toward a more circular construction industry. In this study, the influence of the crushing method is investigated. Samples of five laboratory-made concretes have been crushed using the most common mechanical crushing methods (impact crusher and jaw crusher), and the particle size distribution, morphology, hardened cement paste content and water absorption of the produced RCA have been measured and analyzed. The findings indicate that the use of impact crushers results in the production of RCA possessing more spherical geometric characteristics, albeit with a broader particle size distribution and a relatively higher content of fine particles as compared to those obtained from jaw crushers. Additionally, it is observed that the employed crushing technique seemingly exerts no discernible impact on the hardened cement paste content and the water absorption in the context of the studied concretes.

Characterization and Design of Circular Binders

The concept of a circular economy, where waste materials are transformed into valuable resources, is gaining increasing attention. However, many waste streams are difficult to recycle due to their mixed composition and broad molecular distribution. This paper explores the potential of repurposing mixed materials, specifically focusing on creating a circular alternative to bitumen, a fossil-based binder used in road construction. The molecular weight and composition of bitumen are analyzed using gas chromatography (GC) and infrared spectroscopy (IR). This study proposes using waste plastics and bio-based oils to develop a paving binder with similar molecular distribution. Various plastic types, such as low-density polyethylene (LDPE), high-density polyethylene (HDPE), isotactic polypropylene (PP), polystyrene (PS) and polyethylene terephthalate (PET), are examined for their compatibility with different oils. It is observed that the compatibility of both the molecular weight and composition between the plastic and oil is crucial for the successful dissolution and homogeneity of the binder. Additionally, the crystallinity of the plastic plays a role in the flexibility and durability of the resulting binder. It is demonstrated that by carefully selecting waste materials and understanding their molecular characteristics, it is possible to create circular alternatives to fossil-based materials like bitumen. This approach has the potential to reduce waste, lower dependence on fossil resources, and contribute to sustainable and circular construction materials.

Losing Ground: Targeting Agricultural Land Take by Enabling a Circular Economy in Construction

Among the numerous causes of soil degradation, one of the most severe and difficult to reverse is land take. Land take results in the loss of valuable ecosystem services that negatively impact soil health, especially in agricultural areas. The main drivers of land take are increased provision of housing, schools, hospitals, industrial and commercial sites, transport networks and infrastructures, mines, quarries and waste dumpsites. Globally, the rate and scale of land take is increasing. Given the impact on soil ecosystem services such as the carbon, hydrological and nitrogen cycles, preventing agricultural land take is essential if the triple planetary ecological crises of climate change, biodiversity loss and pollution are to be addressed. Most countries use sustainable management techniques to limit land take by development projects. In this opinion paper, we argue that the circular economy concept could help to establish an alternative perspective on how to understand and address the agricultural land take problem. Law and policy need to foster a systemic transition to a circular economy throughout the entire construction sector’s multiple material life cycles if it is to significantly reduce land take. We use England as a case study to show how the UK government can revise and build on current policy to enable a transition to a more circular construction sector. The case study provides valuable lessons for other countries at a crossroad on land use policy on how fostering a circular construction economy can reduce land take and maintain agricultural soil’s ecological services.

Life Cycle Cost in Circular Economy of Buildings by Applying Building Information Modeling (BIM): A State of the Art

The building industry is one of the largest consumers of materials resources and significant contributors to global waste. Applying core principles of circular economy (CE) could significantly help the environment by reducing waste and decreasing the life cycle cost of buildings. Several strategies to implement the concept of CE in buildings include design for deconstruction, adaptability, and flexibility. However, implementing these design strategies could face constraints. In this study, we identified 22 barriers related to the adoption of CE in buildings, as reported in the literature. We discussed the role of Building Information Modeling (BIM) in overcoming those barriers. This paper demonstrates how BIM can facilitate the implementation of CE principles while providing critical insights into the life cycle costs of circular buildings. We identified 14 ways to use BIM to foster the implementation of a circular economy approach. To achieve these objectives, we have undertaken a thorough review of recent publications that explore CE design strategies, Life Cycle Costing in the circular construction of buildings, and BIM developments in the building industry. This literature review is based on 88 articles covering BIM’s role in enhancing the management of a building’s end-of-life while reducing the life cycle cost in the circular construction of buildings.

Operationalizing contested problem-solution spaces: The case of Dutch circular construction

In shaping collective responses to societal challenges, we currently lack an understanding of how to grasp and navigate conflicting ideas on societal problems and potential solutions. The problem-solution space is an increasingly popular framework for conceptualizing the extent to which problem-oriented and solution-oriented views are divergent. However, this reflexive framework needs an operationalization to become useful in practice. We contribute to this debate by demonstrating how Q-methodology can be used to systematically identify, describe, and compare collectively held visions in relation to problems and solutions. We use the case of Dutch circular construction, and identify three conflicting imaginaries that inform us about disagreement and common ground. We conclude by discussing how policymakers can use different approaches to navigate contestation, presumably mobilizing actors for a collective response.

Spatial Parameters for Circular Construction Hubs: Location Criteria for a Circular Built Environment

Implementing a circular economy in cities has been proposed by policy makers as a potential solution for achieving sustainability in the construction sector. One strategy that has gained interest by both policy makers and companies is to develop “circular construction hubs”: locations that collect, store, and redistribute waste as secondary resources. However, there is limited literature taking a spatially explicit view, identifying the spatial parameters that could affect the locations of hubs both for now and in the future. This study therefore aims to categorize different types of circular hubs for the construction industry, collect spatial parameters required for finding suitable locations for each type of circular hub, and translate the spatial parameters into a list of data and spatial analysis methods that could be used to identify potential future locations. The study used the Netherlands as a case study, extracting spatial parameters from two sources: Dutch governmental policy documents on circular economy and spatial development and interviews with companies operating circular hubs. Four types of circular construction hubs were identified: urban mining hubs, industry hubs, local material banks, and craft centers. The spatial parameters were extracted for each type of hub from four perspectives: resources (such as material type, business model), accessibility (such as mode and scale of transportation), land use (such as plot size, land use), and socio-economic (such as labor availability). The parameters were then translated into a list of spatial data and analysis methods required to identify future locations of circular construction hubs.