Circular Economy for Buildings and Infrastructure

Communities and cities are characterized by a large number of buildings and infrastructure. These buildings and infrastructure (e.g. roads, bridges, power stations, wastewater treatment facilities, etc.) provide necessary functions to the residents of the community. The circularity of buildings and infrastructure, and their components will largely affect the sustainability performance of these communities and cities. In the context of this book, circular built environment covers all efforts that aim to improve the sustainability performance of developments, including material efficiency and energy efficiency. In particular, circularity is taken into consideration throughout its life cycle, e.g. planning, design, use and reuse. Meanwhile, the connection to places and spaces are taken into account. Circularity meant that resources are put back into system as many time as possible so that the demand on virgin materials is minimized.

An inclusive city provides new perspectives for the transition to urban sustainability, with an emphasis on the adaptation of an equilibrium of economic efficiency, environmental responsibility, and social justice. This paper investigates how the circular economy strategy can be better applied in cities on the basis of the perspectives of waste landscape and inclusive community management (relevant facilities and infrastructures), in order to support a more inclusive urban waste management. We begin by conceptualizing the urban system into three boundaries, (1) general geography (GG) representing the overall urban planning scope, such as land use, infrastructure planning, and facility location; (2) physical geography (PG) representing the urban metabolism in terms of material and energy flows; and (3) human geography (HG) representing the socioeconomic activities and agents that acted as the metabolism agents. We further developed a location-based inventory for waste generation based on the statistical data on population, economic outputs, and waste generation by categories, as well as geospatial data including population distribution, land use, housing shapes, and nightlight data. Based on the waste landscape analysis, further inclusive waste management and policy implications are discussed and proposed.

Corporate social responsibility (CSR) and environmental, social, and governance (ESG) are heavily promoted in the construction sector. The target is to realize an inclusive construction in the life cycles. Here, the “inclusiveness” calls for an equilibrium rather than an optimization on the dimensions of social justice, environmental responsibility, and economic efficiency. In realizing this eternal target, an in-depth investigation on how circular economy (CE) will affect the sustainable development goals (SDGs) will be critical. This paper aims to conduct an in-depth analysis on matching how CE policies in the construction sector will affect the 17 social, environmental and economic values in the framework of the SDGs proposed by the UN, respectively. The CE policies in the construction sector are analyzed based on the life cycles in the whole supply chain, from the natural resources mining, transportation of materials, construction materials manufacturing, on-site construction process, to final waste disposal and treatment, including construction-and-demolish waste (C&D waste) recycling. We analyze the policy or the measures in each life-cycle stage, investigating how it would contribute (positive impacts) or affect (trade-offs) the 17 SDGs. Particularly, policies are discussed based on the accounting of embodied carbon in the buildings of the Greater Bay Area (GBA).

This chapter introduces a new method, URECC-LC, for assessing urban resources environment carrying capacity (URECC) from a load-and-carrier perspective, after reviewing existing literature to underline its significance for sustainable urban development. The method, rooted in dynamics discipline principles, views the urban resources environment as a system comprising urban loads (UL) and urban carriers (UC), and measures URECC by considering both elements. This approach not only facilitates effective evaluation of URECC but also extends its implications to sustainable development and urban resilience, and introduces a virtual threshold for its limitations. An application of the URECC-LC method to 35 large Chinese cities demonstrates its effectiveness in assessing urban water resources environment carrying capacity.

Developing recycled aggregate concrete (RAC) offers an effective means of disposing of Construction and Demolition waste (C&DW) while also conserving natural aggregate resources. Despite the clear environmental benefits, RAC is not commonly utilized due to its relatively inferior performance. A promising solution is to develop RAC-based composite components such as recycled aggregate concrete-filled steel tube columns (RACFST). To facilitate the practical application of RACFST where complex load cases are possible, this study investigates the performance of high temperatures damaged RACFST under increased load strain rates via split Hopkinson pressure bar (SHPB) impact tests and numerical simulation. Besides, the influences of various material parameters were analysed to explore optimal design methods for RACFST. Results indicated satisfactory performance of RACFST. The lowest strength ratio of RACFST to normal aggregate concrete-filled steel tube columns still reaches 0.88 (quasi-static, after 700 °C). Simulation research indicated that steel ratio is a more important factor than the strength of steel and RAC in enhancing impact properties. This study further revealed the potential of using RACFST to promote the recycling and application of RAC and create circular economy for sustainable infrastructure development.

The ever-increasing pressure on resources has provided an impetus to the circular economy paradigm, especially in the construction sector. Unfortunately, the construction industry is not easily convinced about the implementation of circular economy strategies without a clear and dynamic overview of the materials demand and supply. An important perspective for such an overview is so called urban resource cadaster that characterizes the urban built environment stocks based on their location, type, quantity, and quality in high spatial and temporal resolution. In this chapter, we detailed the concept, methodology, use cases, and general implications of such an urban resource cadaster. Three case studies were presented based on integrating heterogeneous data through a Geographic information system-based bottom-up material stock analysis with sampled data on building material composition portfolios. The case studies involve the development of an urban resource cadaster for a city in a developed country (Odense, Denmark) and a city in a developing country (Beijing, China) and a global historical subway material stock analysis. Despite Beijing’s massive urban environment, the stock per capita is 140 tons in Beijing, compared to 329 tons per capita in Odense, Denmark. A spatially refined urban resource cadaster can provide a comprehensive overview of the built environment stock and thus assist the decision-makers in the construction industry and the governmental agencies for better urban planning and waste management.

Many are the goals for sustainable housing. These goals are evinced in the United Nations’ Sustainable Development Goals (SDGs) as requirements for adequate shelter. Consequently, various policies have been implemented, yet sustainable housing development remains elusive. This chapter reports a study which models the impacts of various influencing factors (i.e., barriers, risks, and success factors) on attaining the SDGs in housing for sustainable development in cities and communities. Data were garnered via a questionnaire survey of respondents in the formal sector of the Ghanaian housing market. Through the partial least squares structural equation modeling (PLS-SEM), the data were analyzed. Results of the analysis revealed the groups of barriers, risks, and critical success factors (CSFs) which could significantly influence the attainment of the SDGs and circularity (i.e., longer use via maintenance; innovation for adaptability, flexibility, and secondary materials usage) in housing. Findings of the study regarding the barriers and the risks seek to apprise policymakers of primary and secondary factors for efficient resource allocation. Moreover, findings on the success factors could inform policymakers and practitioners on effective and efficient policies for sustainability and circular economy in housing while pointing out policies that could be ineffective and counterproductive.

With the construction of new infrastructure is on the rise in many countries, the impact of the 5G developments on circular economy in the era of COVID-19 cannot be overlooked. However, the high energy consumption and rapid construction speed of new infrastructure have led to increased concern about the carbon emissions generated during the operation process. As 5G serves as the foundation for the construction of new infrastructure, China, as the world leader in 5G base station construction, has already built over 1.4 million 5G base stations in 2021 alone. In the same year, 5G base stations in China produced approximately 49.2 million tons of CO₂eq. In order to increase the contribution of the communication industry to mitigate the global greenhouse effect, future efforts must focus on reducing the carbon emissions associated with 5G base station construction from four key perspectives: network architecture, network deployment, resource scheduling, and link-level technology. In this way, the 5G network can achieve sustainable development.

Despite the noble and aspirational intent of the targets set forth in the Sustainable Development Goals (SDGs), from the global perspective, there is no single country which has completely managed to achieve these targets. However, anecdotal, and empirical evidence suggests a disparity in the progress with developed countries in Europe and North American having made great strides in actualising some of SGD’s targets. In contrast, developing countries, particularly those in sub- Saharan Africa are continuously faced with a myriad of implementation challenges. Critical of these is urbanization, which is considered among the key hindrances towards achieving the SDG 11 due to urban population growth, leading to many countries struggling to meet the population needs such as housing, education, transportation, sanitation, energy, healthcare, and employment amongst others. Therefore, this chapter will focus on SDG 11 (sustainable cities and communities) with emphasis on developing viable solutions intended to address its first target and indicator, namely that of “ensuring access for all to adequate, safe and affordable housing and basic services and upgrade slums”. This indicator is one of the major challenges affecting sub-Saharan Africa region due to little progress made to improve the slum dwellers lives. Using Tanzania as a case study due to its rapid growth in population currently projected at 60 million in 2020, and urbanisation which has contributed towards inadequate housing for a number of decades, the chapter will use theoretical lenses such as Giddens Structuration Theory provide insights into understanding the drivers (influencing the implementation), challenges (for eradication) and practices (for implementing) affordable housing as a solution to addressing some of the objectives of SDGs 11. The chapter will draw on several case studies, definitions, concepts, theoretical models, and applications from a few selected developing countries. Some best practices for actualising Affordable Housing are also proposed.

The U.N. Sustainable Development Goals (S.D.G.s) acknowledge cities as powerhouses of economic growth as evidenced by their contributions to global G.D.P. However, cities nevertheless contribute to 70 per cent of global carbon emissions and over 60 per cent of resource use and are still vulnerable to uncertainties, such as the recent impact of COVID-19. Concepts such as reverse logistics (R.L.) and circular economy (C.E.) sustainable and resilient supply chain (S.R.S.C.) could leverage the transition to sustainable and resilient cities and communities. Therefore, this chapter provides a broad overview of these concepts, highlighting how integrating these concepts, principles, and practices could act as a catalyst for building sustainable and resilient communities. Synergies are highlighted among the practices, principles, and concepts. The chapter explores how the synergistic application of these concepts leads to sustainable communities and cities that thrive on uncertainties, thus seeing them as opportunities rather than threats. In identifying the challenges and risks associated with building resilient communities, this chapter discusses how the concepts of C.E., R.L., and S.R.S.C. come together. Incorporating the resilience concept into sustainable supply chain design and vice versa has been critical to ensuring greater preparedness for the unexpected. The outcome of this chapter is a conceptual framework that describes the mechanisms for integrated circular business models, sustainable and resilient supply chains, and reverse logistics that could be used for the conceptualization of the three concepts (C.E., S.R.S.C. and R.L.) to the sustainable cities and communities attributes. The proposed conceptual framework will provide practitioners and policymakers with a reference model for assessing uncertainties and challenges to achieve the targets set out in S.D.G.s 11. Further, the Circular Business Models (C.B.M.) value propositions at the asset end-of-life stage, and reverse logistics could be used in addressing the key challenges and uncertainties facing resilient communities.

A wide variety of waste products including municipal and industrial wastes have been used in concrete production with this assumption that their utilization in concrete either as binders or fillers can contribute to the sustainability in construction. However, such assumptions may not be true without conducting explicit environmental assessments of concrete and alternative products. This is important because when quantifying their environmental impacts in the context of life-cycle assessment (LCA), depending on the assumptions made, it is possible that wastes and by-products can have higher emissions than the materials that they are intended to replace. To investigate the impact of modelling assumptions, this chapter aims to conduct a detailed LCA for concrete mix designs when considering the utilisation of waste and by-products either as binders or fillers. When considering alternative binders with different allocation methods and transportation modes, the critical transportation distances at which 843 geopolymer concretes (GPC) can be more emissions intensive than their equivalent traditional concretes are identified. In a similar context and through a comparison of emissions factors associated with the preparation of natural and alternative aggregates, the critical transportation distances are also found at which from the context of carbon emissions it is better to utilise naturally available resources or waste products as aggregates. The results reported in this chapter can help understand the impact of different modelling assumptions and to identify the optimum type of concrete in terms of alternative binders and fillers to benefit circular material use in civil engineering.

Green buildings offer an effective solution to reduce carbon emissions, energy consumption, and promote sustainable development. Therefore, it is crucial to promote the growth of green buildings to achieve a circular economy in the construction industry. However, the price premium associated with green buildings, including incremental costs from developers, affects homebuyers’ willingness to pay. Thus, understanding these costs and pricing factors is essential to develop effective green building policies. This chapter provides a comprehensive review of incremental costs, price premiums, and willingness to pay for green buildings. The findings show that although incremental costs remain a challenge to green building development, the critical issue is the poor willingness to pay. Public policies should prioritize the interests of different stakeholders and motivate developers and homebuyers to actively participate in the green building movement.

China produced a large amount of construction and demolition (C&D) waste. Currently, most C&D waste in China is disposed of in landfills, which contradicts the core principles of circular economy, leading to a loss of resources. Although China has placed increased emphasis on the recycling of C&D waste, it is still in its primary stage, indicating that certain challenges might prevent the successful implementation of policies in practice. Therefore, identification of challenges in the development of C&D waste recycling is essential. This chapter employs site visits to five recycling plants in five Chinese cities (Shanghai, Suzhou, Chongqing, Changsha and Shenzhen) and interviews with 12 industry practitioners for examining the challenges. Six challenges are identified: (1) unstable source of C&D waste for recycling, (2) absence of subsidies for recycling activities and high cost for land use, (3) absence of regulations on on-site sorting, (4) unregulated landfill activities, (5) a lack of accurate estimation of waste quantity and distribution, and (6) a lack of an effective waste tracing system. Recommendations to address these challenges are presented. The results of this study are expected to aid policy makers in formulation of proper C&D waste management in China and contribute to sustainable production.

Construction waste produced from rapid urbanisation and population growth has substantial environmental, social, and economic consequences. Although numerous studies have focused on construction waste management strategies and technologies, they have mainly addressed the attitudes and behaviour of the construction site workforce towards waste management mostly during the construction and/or demolition phase. In addition, the number of studies on the architects’ perception and their practical waste minimisation strategies during the planning and design phase is limited. This study developed a model to empirically explore the architects’ real behaviour in implementing waste minimisation strategies which has been justified by the correlation of three theories of planned behaviour, value-belief-norms and institutional theory. Results indicated that architects’ attitude would greatly impact the behavioural intention toward implementing waste minimisation strategies. Also, the behavioural intention was proven influential in explaining architects’ real behaviour in implementing waste minimisation strategies. Conversely, subjective norms, perceived behavioural control, personal norm, and institutional pressures were revealed ineffective on architects’ behavioural intention. The research provides worthwhile insights for the governments and organisations involved in construction waste management from a design perspective and contributes to practice in design and construction industry.

Buildings have been recognized as one of the major carbon emission sources to maintain the basic requirement of building occupants, and occupant has been widely recognized as key building energy end-users. Therefore, to improve building energy efficiency, sensing, recognizing, and utilizing occupancy patterns for building demand-based control are very important and efficient ways. This chapter presents those contents: (i) Occupancy resolution for building energy-savings and its relationship between circular economy at building sector; (ii) Current occupancy sensing and related energy-efficient approach; (iii) Occupancy smart sensing with Wi-Fi network; (iv) One case study of how occupancy sensing can improve building energy efficiency.

A circular economy is a new form of economy that aims to reduce resource usage with effective technological solutions. Eco-feedback systems are a powerful platform to that promoting sustainable behaviors to encourage building residents to save energy usage and participate in the circular economy. This review examines current studies of eco-feedback systems, with a focus on their theoretical foundations and design principles. Two case studies were introduced to illustrate a fully functional eco-feedback system and reveal the major considerations for the design of such a system. The findings of existing research highlight that long-term impact and effective information delivery is the key to promoting behavior changes. Overall, all these studies concluded that as a novel tool to encourage energy conservation behaviors, eco-feedback systems have significant potential in the development of a sustainable society and circular economy.

The increasing urgency to transition towards circular economy (CE) thinking highlights the necessity of improving construction and demolition waste (CDW) management practices. This could be achieved by fostering a waste-free culture within the construction industry with effective stakeholder engagement (SE) by improving relationships between relevant project stakeholders. Thus, this chapter investigates the application of SE in implementing CE principles to improve CDW management in construction projects. To achieve this aim, a literature review was conducted. The findings highlight SE’s importance in establishing and reinforcing a waste-free culture, while demonstrating how SE can lead to a successful transition to CE application in CDW management. Furthermore, the findings reveal that implementing CE practices in CDW management requires the collaboration between various stakeholders and SE is critical in promoting this implementation. Engaging stakeholders can help to build trust and social capital between actors, identify potential barriers to CE implementation and improve the effectiveness and efficiency of CDW management. By engaging with stakeholders and raising awareness of the benefits of circular approaches, a shared understanding of the importance of waste reduction and resource efficiency can be achieved through innovative solutions in the construction industry. Despite challenges in implementing CE thinking in CDW management (e.g., lack of awareness and understanding of CE principles and their relevance to CDW management, conflicts of interest and industry fragmentation), SE can be enhanced through opportunities for collaboration, digital technology adoption and supportive policy interventions. These findings can assist construction professionals to improve CDW management by applying SE to construction projects.

Regency Road to Pym Street Project (R2P Project) comprises an at-grade motorway from the existing motorway infrastructure to the north (South Road Superway); an overpass of the motorway over Regency Road; and an at-grade motorway from Regency Road to Pym Street, transitioning to the lowered motorway infrastructure (Torrens Road to River Torrens Project). The Australian and South Australian governments have jointly committed $354.3 million to construct the Regency Road to Pym Street (R2P) Project as part of their overall commitment to build a non-stop North-South Corridor. The R2P Project is the first project in Australasia to obtain a certified Infrastructure Sustainability Council of Australia V2.0 Design Rating. The R2P Project is contractually required to achieve a Bronze rating at completion, however, the R2P Project has exceeded this requirement for the design phase, achieving a Gold level rating. Reduction of greenhouse gas emissions during the construction and operation of the R2P Project is achieved by: lower wattage road lighting; use of GreenPower at the Polonia Reserve Compound; and use of materials with lower greenhouse gas emissions (use of recycled asphalt pavement, reduced Portland cement concrete and recycled materials in kerbing). This chapter will showcase how circular economy was taken into consideration from design to construction, and the outcomes.

The management of construction and demolition (C&D) waste is a serious concern across the globe. The construction and demolition sector accounts for over 40% of all waste from Australia with a recycling rate of almost 75% in some states. Thus, the largest contribution of this process is the diversion of waste materials to landfill. This study focuses on the life cycle assessment of the production of recycled aggregate product of a recycling plant in Australia and presents a comparative assessment of recycled aggregate products from the processes and the production of Virgin materials. Several scenarios are also conducted to examine the efficiency of the processes through transportation. The Australian Life Cycle Assessment Society (ALCAS) Best Practice Life cycle impact assessment (LCIA) carbon neutral Method was used for the assessment. The results demonstrated that, the greenhouse gas emission reported as 4.88E+00 kgCO2eq is lower than the LCA on quarry products for natural aggregates in Australia which is 11.3E+00 kgCO2eq. Recycled aggregate produced from the plant reduces the carbon footprint by approximately 57% as compared to that of the quarry (natural aggregate) production. The results also reveal that, alternative sources to transportation can severely affect the carbon footprint of the recycled products and process. It is recommended that; precise data and information should be collected to reduce inaccuracies. Moreover, information on cost and prices were limited, therefore, the life cycle costing (LCC) assessment is not performed for this project, this is a good opportunity to establish further research on costs associated with the recycling of C&D waste at the plant.

Roads are one of the key components to ensure modern societies’ ‘normal’ functioning. They are critical infrastructures that maintain interconnectivity among communities and promote economic growth and improvement for sustainable development. Therefore, roads play a crucial part in achieving sustainable cities and communities aligned with the 11th Sustainable Development Goal (SDG). As reported within this chapter, road projects account for high CO₂ emissions with significant energy and material consumption throughout their lifecycle. The implementation of circular economy (CE) practices regarding resource consumption in the different stages of road projects have been proposed by several researchers as a strategy to address the depletion of natural resources. This chapter intends to review current strategies together with enablers and barriers to implementing circularity in road infrastructure projects to reduce the depletion of natural resources. The main results show that by addressing enablers and barriers, it is possible to improve the level of CE implementation in practice, leading to more sustainable energy-saving solutions and efficient use of resources to help stakeholders in the assessment and selection of the most effective solutions for road infrastructure projects.

Construction and demolition (C&D) waste is one of the most significant waste streams. Waste generation quantification provides the fundamental information for CD waste management. Without understanding the waste type and amount, it would be impossible to propose strategies to reduce and recycle the waste. Compared to construction waste, renovation waste received much less attention. BIM emerges as a potential solution to incorporate waste management considerations into the design from the beginning of projects, but limited studies apply BIM to improve CD waste management activities. This study aims to propose a prototype Revit-plugin enabling automated waste quantification at the early design stage. Based on available Revit models and rational assumptions, the plugin can estimate both the waste generated at the construction stage, and generated at the operational stage due to material replacement in renovations. It provides waste information enabling architects to optimise material selection at the early design stage thereby reducing waste generation at the later construction and operation stage.