Circular Construction Research Articles

A comparative analysis of quantification and validation methods for prospecting the anthropogenic mine as material reserve for circular construction

Globally, buildings account for at least 39% of CO2 emissions and more than 50% of resource extraction and solid waste production. Therefore, any transition to carbon neutral buildings must be paired with new resource sensibilities and a shift from linear models of material consumption to continuous material use within a circular economy. Prospecting the (urban) anthropogenic mine represents an essential step towards circular construction and requires a robust methodology for data collection and interpretation. This paper presents a comparative analysis of survey methods, evaluated by parameters of time, accuracy, equipment, and labor to determine the ability of each tool in providing the necessary data to activate the existing built environment as a material resource. Chosen methods span from on-site manual and analog surveys to off-site digital technologies on a variety of case study scales. In all cases, the output’s data format (sketch book, images, mesh or point cloud outputs) can be cumbersome to process with CAD and BIM software, increasing time to results and limiting the technology’s potential, introducing the call for a new generation of survey tools specifically addressing the needs of deconstruction and salvage in circular construction.

Upscaling non-residential bio-based circular construction in the United Kingdom

Non-residential circular construction projects using bio-based materials have been realised in the United Kingdom. Case studies include the Adnams Distribution Centre, the University of East Anglia’s Enterprise Centre and the British Science Museum’s hempcrete storage facility. The bio-based buildings utilise the natural properties of bio-based materials to insulate and regulate internal environments, particularly with reducing fluctuations in temperature and relative humidity, which can be harmful to sensitive stored products and artefacts. Projects have been successful on both on environmental and physical performance levels; however, they have not led to a subsequent proliferation of non-residential large-scale circular projects within the UK using emerging bio-based materials. This study examines why and uses analysis based upon exclusive interviews with key figures associated with bio-based case studies. Challenges faced include the ability to upscale production by manufacturers of bio-based materials, problems surrounding initial costs, gaining accreditation for materials, the vested interests present in the construction industry and levels of knowledge among clients and construction professionals. Potential upscaling solutions identified include long-term financial savings on running costs and high staff productivity, policies regarding grants, incentives and planning applications and local economic regeneration.

CO-CREATING SYSTEMIC CHANGES FOR A CIRCULAR ECONOMY IN/UNDER CONSTRUCTION, PRELIMINARY LESSONS FROM THE FLEMISH LIVING LAB ON CIRCULAR CONSTRUCTION

Like any persistent challenge, the transition from a linear to a circular construction economy requires systemic changes. To divert from current practices that maintain the take-make-waste logic, we need new ways of doing and thinking within the value network of construction. In search for those enduring changes, a compass group advises the Flemish Living Lab on Circular Construction. This lab is a three-and-a-half-year project of study and experiment initiated by policy. During four participatory workshops, the compass group identified the most important system hurdles and necessary changes for achieving a circular construction economy, through subsequent steps of system analysis, translation and reflection. These outcomes have been synthesized and validated during the last workshop and are presented in this paper as a preliminary outcome of lab. Further, by bringing together forerunners of construction and co-creating together new knowledge, it is demonstrated how a well-guided compass group allows to bring into practice ‘participatory system modelling’. By consequently translating the resulting insights into the requirements for a targeted call for experiments, it is finally shown that this co-created knowledge has been ‘actionable’ for the policy makers of Circular Flanders, and triggered dozens of partnerships to submit an experiment.

Developments to come to a circular construction economy; experiences in facilitating a local soil and sand depot

In the construction industry the ambition to come to a circular economy will, with its vast material usage, be a hard nut to crack. This paper describes a research project part of the H2020 Cityloops project, in which it was expected that soil and sand depots could be an interesting subject to study. Already for many years and in multiple municipalities, these depots help to overcome mismatches regarding quality and quantity in demand and request of soil and sand. With the ambition to close material loops the construction industry might experience these kinds of mismatches also for an increasing number of other resources in the nearby future. Having positive experiences with her soil and sand depot, the municipality of Apeldoorn was open to give insights in the flows at her open-air soil and sand depot. The conducted research helped making processes transparent and valuable insights were gained. However, considering the great variety in building materials, products and components, it currently seems possible to handle only a small number of other material flows in the same way soil and sand are being handled and stored at a depot.

Circular building with raw earth: a qualitative assessment of two cases in Belgium

The built environment puts high pressure on our planet, and a great deal is related to resource extraction, material production and waste generation. In the context of circular construction, buildings must be designed and built in order to keep our natural resources in closed material loops for as long as possible. Raw earth has regained attention in the building industry as an abundant, low-impact and highly recyclable building material. However, little is known and experienced about the implementation of raw earth in circular building design. Therefore, this research offers a better understanding of the circularity of earth architecture by assessing two contemporary Belgian cases. Based on literature, semi-structured interviews and the analysis of technical documents, the circularity of the two cases is qualitatively assessed at different scales and levels. It appears that circularity is highest on the material scale and lowest on the building scale for both cases. It is also found that earth as a building material does not easily fit in existing circular assessment frameworks. This investigation represents a contribution towards the development of design support for circular building with raw earth.

Green public procurement: learnings from Pesaro city, Italy

The development of mandatory green public procurement requirements is a significant and tangible contribution to undertaking planned, sustainable deconstruction (rather than demolition) approach to increase recycling materials, creating new businesses and new green jobs. Research undertaken of a procurement process for Pesaro, Italy demonstrates the application of an assessment approach and method based on holistic evaluation and interpretation of multiple sustainability aspects of buildings and their parts. Taking a holistic life cycle approach, this case study provides a clear evidence of how to foster ‘circular’ alternatives compared to linear, business as usual options in the management of public procurement. A competitive procedure in the procurement process was undertaken resulting in materials either being reused or taken to a recycling centre. The reuse of the materials during the new construction phase also included monitoring the quantity of all materials, preventing any waste and encouraging optimised reuse. This study shows that it is possible to drive the market towards a circular thinking and a circular construction site management is a critical requirement for transitioning towards a circular built environment. By ensuring that tendering processes support and develop sustainable recovery of waste materials, this study shows that it is possible to provide materials second and third life.

IMPLEMENTATION STAGE FOR CIRCULAR ECONOMY IN THE DANISH BUILDING AND CONSTRUCTION SECTOR

The building and construction sector is selected by the European Commission as a key product value chain in the transition towards circular economy (CE) due to the major resource consumption, waste generation and GHG emissions from this sector. This paper reports the result from qualitative and semi-structured interviews with 30 Danish stakeholders from the sector on the current stage of implementation of CE and the research/innovation needs to scale circular construction from niche to mainstream. The interviews showed a large variety in the stakeholder’s stage of transition from hardly knowing the term to having CE as a major driver in their business. Some meant that scaling of CE is close to impossible and that material reuse will never develop to more than a niche, whereas others already offer full-scale circular solutions to clients. The interviews pointed at a need for a common definition and terminology for CE, methods for documenting the gains from the circular solutions (economic and environmental), methods for technical documentation of the quality of reused materials, processes which enables scaling, methods to implement CE in various systems such as digitalization and building passports, new value chains and framework conditions in support of circularity. Regardless these needs, demonstration projects of major importance to gain general knowledge have been built or are planned in Denmark. These demonstrations have different approaches: using todays waste from different industries as construction materials; reusing construction materials (the basic building, elements or processed materials); and designing new buildings for disassembly to enable future reuse.

Circular Construction Process: Method for Developing a Selective, Low CO2eq Disassembly and Demolition Plan

With the increasing focus on the construction sector (e.g., following the European Green Deal initiative) with the aim to reduce emissions by 55% by 2030 (compared to 1990 levels), as well as achieve full decarbonisation by 2050, the built environment remains a strategic domain for the R&I (Research and Innovation) agenda. Indeed, the building and construction sector is the main contributor to greenhouse gas emissions (39% of global emissions as of 2018), highlighting the need to start a process of decarbonisation of this sector. The overall reduction in the environmental impact of building materials is achieved by establishing sustainable continuity between the end-of-life phase of the building and the production phase of individual building components. In particular, with reference to the end-of-life phase of the building (BS EN 15978: 2011), the Minimum Environmental Criteria foresee the preparation of a plan for the disassembly and selective demolition of the building, which allows the reuse or recycling of materials, building components and prefabricated elements used. According to the guidelines of a low-carbon construction design, which takes into account a circular economy, the following thesis deals with a methodological proposal to study “dry” construction systems (wood and steel). In particular, the study intends to reach the development of such an elaboration by carrying out an assessment of the environmental impact of a process of selective disassembly and demolition of steel building systems. The model is developed on the basis of a reading of the level of sustainability of emblematic case studies, appropriately identified, i.e., ‘quality’ architectures, built with ‘dry’ (steel) building systems.

Bioclimatic and Regenerative Design Guidelines for a Circular University Campus in India

To transform the negative impacts of buildings on the environment into a positive footprint, a radical shift from the current, linear ‘make-use-dispose’ practice to a closed-loop ‘make-use-return’ system, associated with a circular economy, is necessary. This research aims to demonstrate the possible shift to a circular construction industry by developing the first practical framework with tangible benchmarks for a ‘Circular University Campus’ based on an exemplary case study project, which is a real project development in India. As a first step, a thorough literature review was undertaken to demonstrate the social, environmental and economic benefits of a circular construction industry. As next step, the guideline for a ‘Circular University Campus’ was developed, and its applicability tested on the case study. As final step, the evolved principles were used to establish ‘Project Specific Circular Building Indicators’ for a student residential block and enhance the proposed design through bioclimatic and regenerative design strategies. The building’s performance was evaluated through computational simulations, whole-life carbon analysis and a circular building assessment tool. The results demonstrated the benefits and feasibility of bioclimatic, regenerative building and neighbourhood design and provided practical prototypical case study and guidelines which can be adapted by architects, planners and governmental institutions to other projects, thereby enabling the shift to a restorative, circular construction industry.

Sustainability of the build environment and its impact on user performance. Case study Polis University

<p>The built environment is important not only for its users and owners, but also for the community and society as a hole, and yet, construction is one of the most energy consuming, destructive, and moreover material consuming industries. Deficiencies with adaptability to meet changing needs in terms of sustainability in architecture can eventually cause needless costs, environmental pressure and dissatisfaction. The aim of this study is to explore whether the circular construction and sustainability of built environments is not only a matter of reducing environmental impacts and limiting the use of non-renewable resources, but it can be successfully used to enhance of environmental protection, social equity, and economic development of a facility. Furthermore, the study tries to understand whether we can use circularity principles not only for the building to be more sustainable and in line with circular economy principles, but also be used to enhance user performance, in this specific case the performance of student and academic staff. The study was applied to Polis University and its premises. Two survey formats were specifically designed to collect data on overall functionality and comfort of Polis University facilities, as well as data on academic staff and student self assessment performance. The study emphasizes the importance of the elements of sustainable built environment, and the care that designers and builders need to achieve what is called optimal comfort and functionality of each element, keeping in mind not only end users but also environmental, social and economical aspects as a fully accomplished sustainable architecture design.</p>

Reusing railway infraestructures in the spirit of circular construction. A contribution to an operational concept

<p class="Abstracttext-VITRUVIO">This paper aims to be a contribution to establish a position to the reuse of obsolete railway buildings in the field of circular construction. Recent discussions argue that considering that the circular economy is only related to the use of materials or waste is a misconception. The reuse of buildings is also an issue circular architecture. The European Union itself, since 2002, supports the Programme ESPON - European Territorial Cooperation Programme, which incisively inserts obsolete buildings in the "spirit of the circular economy", giving greater attention to industrial areas undergoing change and deindustrialisation. Considering that the concepts of circular construction and circular architecture originated in the circular economy, which emerged as a way to promote and ensure urban sustainability, this article addresses in a first moment the concept of circular construction from the first documents developed in the context of sustainable development to the latest policies proposed by ESPON. It also analyses the reuse of obsolete railway spaces based on the analysis of some emblematic examples of reuse, namely the <em>Musée d'Orsay</em> and the <em>Promenade Plantée</em> in Paris. These two examples represent different types of railway infrastructure and their fate will frame the reuse of railway buildings within the concept of circular construction.</p>

Sustainable and traditional technologies in Kutahya historic houses and their contribution to circularity: the case of Lajos Kossuth house

<p>It is important to preserve historic buildings in their original conditions, not only to protect building integrity but also to sustain Traditional Knowledge Systems. As stated by ICCROM, those Traditional Knowledge Systems play an important role in the conservation and management of heritage. Among them, building service systems including heating, cooling, ventilation, lighting, drainage, and their architectural construction technology help sustain heritage buildings and extend their life cycle with a minimum level of energy demand. Passive survivability means also contribute to comfort conditions, opening new scenarios for the designing of contemporary buildings. Hence, in this research, first, traditional Kutahya houses were examined in terms of their construction, technology, and architecture. Then, among them, Lajos Kossuth House, dated the 18<sup>th</sup> century, has been chosen as an exemplary to investigate its traditional building service systems in more detail from the point of circularity in construction, their contribution to circular economy, Cradle to Cradle (C2C) strategies, and design for adaptability principles (DfA). It is observed that they are mostly in a well-preserved condition in terms of both function and character-defining features. However, after 1982, during its refurbishment work to be used as a museum, some of its original details, especially the ones related to waste and clean water were destroyed. To be able to sustain and protect the rest of the original service systems and related architectural construction details in this case study building, they should first be documented, well defined and their recognition should be increased to serve as a model for the maintenance of similar building systems. In addition, it might be possible to transfer the knowledge of those passive survivability means and circular construction principles to contemporary buildings.</p>

A circular construction evaluation framework to promote designing for disassembly and adaptability

This paper formulates a concise, free-to-use Circular Construction Evaluation Framework (CCEF) based upon international design code guidelines to assess and quantify the circularity credentials of an existing or proposed construction project. Central to the principles of circular construction is designing for disassembly and adaptability - the ability of a building's elements and connecting components to be disassembled and reused, or rearranged, after the initial design life. Analysis of modern methods of construction and the compatibility of systems with the concepts of designing for disassembly and material reuse inform the development of the CCEF. Circular construction is facilitated by simplicity, standardisation and modularity in design, sustainably-sourced materials, transparent and accessible mechanical connections and the adoption of a manufacturing-style approach towards durable and reusable standardised components and materials. The CCEF allows users such as clients, consultants, contractors, local and national planning and infrastructure policy professionals to evaluate both whole building and elemental levels at the early design and planning stages in a new-build, refurbishment or renovation project. Implementation of a scoring system is demonstrated by the evaluation of example buildings with varying usage of conventional and bio-based materials. It is shown by use of the framework that a simple standardised construction using reversible connections and previously used material elements rates highly, demonstrating a greater extent of circularity in the construction.

Circular economy in the construction industry: An overview of United States stakeholders’ awareness, major challenges, and enablers

Increasing environmental concerns and resource scarcity risks have drawn attention to a Circular Economic (CE) model during the last decade. Nevertheless, literature related to the state of practice of CE in the built environment in the United States (U.S.) is still limited. In this context, this study investigates U.S. architectural, engineering, and construction (AEC) industry stakeholders’ awareness of CE. The investigation also covers major barriers for the implementation of strategies aligned to the CE model, and enabling factors for a transition from a linear economic model to a CE model in the construction industry in the U.S. A mixed-methods approach was deployed through a combination of online survey and interviews with AEC industry stakeholders from different regions of the U.S. Results revealed that some strategies are widely disseminated (i.e., open-loop recycling, selective demolition, and prefabrication), whereas others are hardly adopted (i.e., design for disassembly, design in layers, closed-loop recycling). Additionally, findings indicate budget and upfront costs, project schedule and timeline, lack of awareness and regulations, and current business models as major barriers for the implementation of strategies aligned to a CE model. Furthermore, four enabling factors for a transition to a CE model in the construction industry were identified (i.e., education and cultural change, data availability, policies and incentives, and novel voluntary stewardships). Notably, contributions of this study include fostering a much needed debate around circular construction and its challenges, and expanding the limited existing body of knowledge.

Strategies for a Circular Economy in the Construction and Demolition Sector: Identifying the Factors Affecting the Recommendation of Recycled Concrete

With increasing urbanisation, new approaches such as the Circular Economy (CE) are needed to reduce resource consumption. In Switzerland, Construction & Demolition (C&D) waste accounts for the largest portion of waste (84%). Beyond limiting the depletion of primary resources, implementing recycling strategies for C&D waste (such as using recycled aggregates to produce recycled concrete (RC)), can also decrease the amount of landfilled C&D waste. The use of RC still faces adoption barriers. In this research, we examined the factors driving the adoption of recycled products for a CE in the C&D sector by focusing on RC for structural applications. We developed a behavioural framework to understand the determinants of architects’ decisions to recommend RC. We collected and analysed survey data from 727 respondents. The analyses focused on architects’ a priori beliefs about RC, behavioural factors affecting their recommendations of RC, and project-specific contextual factors that might play a role in the recommendation of RC. Our results show that the factors that mainly facilitate the recommendation of RC by architects are: a senior position, a high level of RC knowledge and of the Minergie label, beliefs about the reduced environmental impact of RC, as well as favourable prescriptive social norms expressed by clients and other architects. We emphasise the importance of a holistic theoretical framework in approaching decision-making processes related to the adoption of innovation, and the importance of the agency of each involved actor for a transition towards a circular construction sector.

Circular vs. linear economy of building materials: A case study for particleboards made of recycled wood and biopolymer vs. conventional particleboards

This paper proposes the assessment of particleboards based on the Circular Economy (CE) approach, in which wood wastes and bio-resins are used to produce circular construction materials and compare them with conventional panels made of synthetic polymers and virgin wood particles. The use of discarded wood in particleboards aims to provide circular routes for this solid waste instead of the landfill after use. In addition, two bio-based polyurethane (PU) and urea–formaldehyde (UF) polymers are compared for the production of particleboards. The alternative particleboards are made with raw wood shavings of the species Pinus taeda, Pinus elliotti and Eucalyptus urograndis, without sifting processing. The particleboards are evaluated by the screw pull-out tensile test, three-point bending test, swelling after water immersion and colourimetry. Additional analyses such as surface roughness, thermal conductivity, apparent porosity and scanning electronic microscopy are performed for the characterisation of the panels. The technical viability of particleboards is obtained by mechanical analysis for higher density composites of PU polymers and eucalyptus wood. Finally, a life cycle assessment of particleboards made from recycled wood and bio-resins reveals that all scenarios for the production of particleboards in a CE approach are environmentally benign alternatives, reducing up to 95% of the environmental impacts to human toxicity, abiotic depletion and other impacts compared to the traditional and linear scenario. The best circular scenarios are more sustainable than linear scenarios, especially for the cases of particleboards are made with medium densities involving eucalyptus or pinus wood wastes and PU polymer.

IMPACT OF CIRCULAR CONSTRUCTION ON DEMOLITION WASTE MANAGEMENT IN THE INDIAN CONSTRUCTION INDUSTRY

In recent times due to the Indian economic growth, there is a surge in construction activities. This surge has led to an excess amount of demolition waste that is produced. According to the Building Material Promotion Council, India generates an estimated 150 million tons of C and D waste every year. Some existing initiatives and the significant stakeholders' involvement have created the demolition waste management systems essential in the building’s demolition phase. The research in the C and D and Awareness program for C and D waste that initiated has led to the implementation of some waste management systems in the building's demolition phase. In India, the amount of demolition waste produced is higher than the construction waste produced while constructing buildings. So, it is essential for the demolition waste mitigation plan in the building's demolition phase. The study aims to know circular construction and current demolition waste management performance in the Indian construction industry. Through literature review, demolition waste management systems that are carried out all around the world are collected. The current practices carried out by different stakeholders practicing in India are known through a questionnaire survey. Data interpretation is made using the data collected in the literature review and the questionnaire survey. This research identified the significant benefits, barriers, and motivation factors to implement the waste management system, and proposing any necessary changes. Designer innovation and BIM deconstruction is considered as one of the barrier-breaking innovation in adopting the circular construction.

Towards Circular Economy through Industrial Symbiosis in the Dutch construction industry: A case of recycled concrete aggregates

Since 95% of the Construction and Demolition Waste (CDW) is down-cycled and the material value is not effectively recovered, the Dutch construction industry strives for implementing Circular Economy (CE). From the recycling/reusing perspective, a key enabler towards CE is Industrial Symbiosis (IS). Although IS has been widely applied in manufacturing industries, its implementation is unclear in the construction industry. Particularly, the potential IS economic convenience is hard to predict in the highly fragmented construction supply chain. This study explores the IS based on the Recycled Concrete Aggregates (RCA) in the context of a concrete waste supply chain in the Twente region of the Netherlands. The research tackles with the CE challenge of lacking economic incentives by investigating the Industrial Symbiosis Network (ISN) emerged by replacing Primary Concrete Aggregates (PCA) with RCA. An Agent-Based Modelling (ABM) approach is proposed by integrating Geographic Information Systems (GIS) to present the dynamic supply-demand of RCA. Besides, supply chain actors are simulated as negotiable agents in a platform model to reveal the IS collaboration dynamics under different economic scenarios. It is found that the IS exists in the construction industry but only in an implicit manner because the RCA treatment requires the collaboration of multiple actors across substantial temporal and spatial differences. The study enriches the IS taxonomy by defining Implicit IS and provides instruments to support the decision-making of business collaborations and policy-making for a circular construction industry.

Machine Learning in Hazardous Building Material Management: Research Status and Applications

Assessment of the presence of hazardous materials in buildings is essential for improving material recyclability, increasing working safety, and lowering the risk of unforeseen cost and delay in demolition. In light of these aspects, machine learning has been viewed as a promising approach to complement environmental investigations and quantify the risk of finding hazardous materials in buildings. In view of the increasing number of related studies, this article aims to review the research status of hazardous material management and identify the potential applications of machine learning. Our exploratory study consists of a two-fold approach: science mapping and critical literature review. By evaluating the references acquired from a literature search and complementary materials, we have been able to pinpoint and discuss the research gaps and opportunities. While pilot research has been conducted in the identification of hazardous materials, source separation and collection, extensive adoption of the available machine learning methods was not found in this field. Our findings show that (1) quantification of asbestos-cement roofing is possible from the combination of remote sensing and machine learning algorithms, (2) characterization of buildings with asbestos-containing materials is progressive by using statistical methods, and (3) separation and collection of asbestos-containing wastes can be addressed with a hybrid of image processing and machine learning algorithms. Analysis from this study demonstrates the method applicability and provides an orientation to the future implementation of the European Union Construction and Demolition Waste Management Protocol. Furthermore, establishing a comprehensive environmental inventory database is a key to facilitating a transition toward hazard-free circular construction.

Expression profile of circular RNA and construction of circular RNA-Micro RNA network in salivary adenoid cystic carcinoma

BackgroundCircular RNAs (circRNAs) is a newly discovered type of non-coding RNA, the abnormal expression of which has been demonstrated in many types of human tumors. So they have been considered as promising candidates as diagnostic and therapeutic targets in cancer. This research aimed to screen the profile of circRNA expression in salivary adenoid cystic carcinoma (SACC).MethodsUsing the threshold of FDR < 0.05 and fold change > 2 or < 0.5, 5 up-regulated and 26 down-regulated circRNAs were identified. The reliability of sequencing was verified by the expression detection of randomly selected circRNAs via qRT-PCR.ResultsMoreover, the circRNA-miRNA system was established by bioinformatics approaches and successfully identified an interaction between circRNA ABCA13 and a cancer-related miRNA (miR-138-5p), which was also verified by qRT-PCR. Moreover, the predicted molecular interaction proved that circRNA ABCA13 may promote SACC through inhibition of miR-138-5p.ConclusionsCollectively, this study has offered the first report about the circRNA expression profile and circRNA-miRNA network in SACC. All of the above could benefit the exploration of novel therapeutic target in SACC treatment.