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The construction industry continues to play a significant role in the economic development of most nations in the world. However, the construction sector still follows the 'linear' 'take–make–dispose' industrial model that, having benefited development, plays a major factor in the depletion of resources, environmental deterioration, and the generation of waste and pollution. In this regard, the adoption of a circular economy (CE) presents a compelling opportunity to address the challenges derived from the traditional linear economic model. This study attempts to scrutinise the critical success factors (CSFs) for implementing a CE via a mixed-method approach that combines both focus groups and an online survey. The adopted approach ensures a comprehensive identification and prioritisation of CSFs for implementing CE principles in building construction projects. The focus groups consisted of 20 key stakeholders drawn from prominent construction firms which included clients, consultants, contractors and designers. The outcomes from these focused groups led to the dentification of 43 CSFs, later categorised across different dimensions. Subsequently, an online survey was conducted to establish a priority list of the identified CSFs, using responses from 82 stakeholders to rate their level of importance. The top five significant CSFs include ensuring the use of standardised and warranted secondary materials, maintaining cost equivalence between a CE and linear approach, maintenance and operation cost minimisation, assessment of life cycle cost (LCC), and the enforcement of robust government regulations and policies that prioritise a CE. The Relative Importance Index (RII) was used to rank the identified CSFs following results obtained using the Statistical Package for Social Sciences (SPSS 27) and Excel for Microsoft 365. The findings of this study can inform the creation of decision support systems that could progress a CE across the construction project life cycle. [ABSTRACT FROM AUTHOR]

The implementation of a circular economy (CE) in the construction sector faces several challenges that hinder its progress. Research on the awareness, key enablers, and potential benefits of CE in Saudi Arabia's construction of mega-projects that could contribute and promote a successful transition is still at its early stages and remains limited. This study delves into CE awareness and understanding, identifying the key enablers that could support its successful adoption in Saudi Arabian mega-projects and the potential benefits associated with it. To achieve this, a comprehensive literature review was conducted, followed by 18 semi-structured interviews across three case studies, which involved the main stakeholders in building, urban development, and infrastructure projects. The findings, which are thematically analysed, revealed that CE awareness mostly focuses on reuse, recycle, and waste reduction. A significant gap in the knowledge of circularity throughout projects' lifecycles has been identified. As such, this study concludes that the key enablers for CE include establishing regulatory frameworks, enhancing professionals' awareness and education, promoting the use of advanced technology, ensuring a mature market, and supporting CE initiatives. Moreover, the potential environmental and socio-economic benefits of CE, such as cost reduction, environmental impact reduction, and better-improved quality of life are crucial for encouraging a wider implementation of CE in the construction of mega-projects in Saudi Arabia. [ABSTRACT FROM AUTHOR]

The construction sector has been subjected to scrutiny due to its propensity for waste generation and the extensive utilisation of finite natural resources. In response to these concerns, a transition towards a novel conceptual framework known as circular economy (CE) has been advocated. Nevertheless, the integration of CE principles within the construction domain encounters numerous impediments to its advancement. Despite scholarly recognition of these challenges, scant research has been devoted to elucidating the intricacies associated with the planning and execution of large-scale projects, particularly within developing nations such as the Kingdom of Saudi Arabia (KSA). This paper intends to fill this gap through the identification and ranking of those barriers encountered when trying to implement CE during construction in KSA. To this end, a comprehensive literature review was completed, alongside a survey conducted amongst 239 participants involved in three mega-projects. A statistical analysis of the data collected was carried out based on the one-way analysis of variance (ANOVA). Following this, a relative importance index (RII) was established to rank 24 barriers categorised as major within the sample. The findings revealed the lack of regulation within the construction sector, the lack of education and training, little awareness and guidance on the subject, and the absence of an incentives policy as primary barriers to adopting CE in KSA. The present study endeavours to enhance the comprehension regarding the principles of circular economy (CE) and the attendant challenges encountered during its implementation. The overarching objective is to provide insights that can inform decision-making processes, thereby facilitating the development of robust mitigation strategies and the adoption of best practices. [ABSTRACT FROM AUTHOR]

The response to the climate emergency requires solutions that address multiple sustainability targets, which could be conducted by merging scientific research from areas that have traditionally evolved separately. This investigation presents advances in that direction by studying a building prototype designated for vertical farming, which enables the wind energy potential across built-up areas to be explored, in this case through the implementation of micro-wind turbines on the surface of the prototype. The study includes a parametric analysis consisting of varying locations of wind turbines across the building envelope, and the width of ventilation corridors. The effects of different widths of outdoor ventilation corridors, various locations, and additional wind angles on the capacity to harvest wind resources were investigated. The results showed that the 5 m wide outdoor corridor has the best ventilation effect, and the wind turbine placed on the roof has the best wind energy potential. The efficiency of wind turbines decreases significantly when multiple devices are placed at the same height on the façades, although overall, the potential for energy harvesting seems incremental. [ABSTRACT FROM AUTHOR]

Offshore wind farms are great options for addressing the world's energy and climate change challenges, as well as meeting rising energy demand while taking environmental and economic impacts into account. Floating wind turbines, in specific, depict the next horizon in the sustainable renewable energy industry. In this study, a life-cycle cost analysis for floating offshore wind turbines is developed by combining the most recent data and parametric formulas from databases and relevant papers. The cost analysis models focused on cost minimization with special emphasis on Operation and Maintenance Cost (OPEX), Decommissioning Cost (DECOM), and Levelized Cost of Energy (LCOE), which are important factors in wind power economy. Given that floating wind energy is still developing, the presented scenarios should be beneficial in making future decisions. The cost analysis scenarios include on-site and off-site maintenance scenarios for OPEX. In addition, four alternative scenarios for DECOM have been examined: mechanical recycling, mechanical-incineration, incineration processes, and landfill. According to the findings of these scenarios, OPEX varies from 16.89 to 19.93 £/MWh and DECOM between 3.47 and 3.65 £/MWh, whilst the total LCOE varied from 50.67 to 66.73 £/MWh. [ABSTRACT FROM AUTHOR]

The building sector is a major contributor to global resource consumption and waste generation. The circular economy (CE) concept offers a promising alternative to the traditional linear economy by promoting the reuse, remanufacture, repair, and recycling of materials and products. However, the adoption of CE in the building sector faces several barriers. This paper presents a systematic literature review utilising the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) approach, focusing on the barriers and enablers influencing the adoption of the CE concept in the building sector. Drawing from an analysis of numerous papers published between 2008 and 2023, we identified a high number of barriers and enablers that delay the integration of CE. The barriers were categorised into six categories: awareness, technical, economic and market, implementation, support/promotion, and social. The paper also discusses the interdependence of the identified barriers, using a co-occurrence matrix. The study findings indicate lack of CE regulations, fragment supply chain, and high upfront investment cost as major barriers to the implementation of CE in the building sector. Based on the study results, stringent governance and legislation, financial incentives, and the development of technology and innovation for circular building tools are critical factors for the successful implementation of CE principles. The results of this study provide a comprehensive overview of the feasibility to CE adoption in the building sector, which could also help to develop strategies to accelerate the transition to an integrated CE. [ABSTRACT FROM AUTHOR]