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.
The limits to linear models of production based on material extraction, manufacture, use, and disposal are becoming increasingly apparent across the global economy. The Circular Economy (CE) describes an alternative to this problematic “take-make-waste” linear model that is concerned with resource efficiency and waste minimization. The construction and demolition sector represents an important focus for a CE transition due to its significant environmental impact. The use of thermal insulation to reduce energy demand associated with heating and cooling in buildings is vital for reducing the sector’s high environmental impact; however, there are significant challenges to recycling thermal insulation materials (IM). This study examines these challenges in the context of Switzerland and evaluates the potential for more circular management of expanded polystyrene and stonewool IM. The research provides an original analysis of the Swiss IM value chain in the context of the CE agenda based on a literature review, semi-structured interviews, and a workshop. Research gaps are highlighted based on scientific literature. The roles and agency of actors involved in the Swiss IM value chain are examined. Enablers of and barriers to wider IM recycling as reported by workshop participants are outlined. Interventions for tackling the current challenges faced for the recycling of thermal IM are suggested. Finally, an agenda for future research is proposed. Throughout the discussion, the importance of the involvement, commitment, and collaboration of stakeholders across the entire IM value chain for an effective and expedient transition to a CE is highlighted.
Urban greening has great ecological, social and economic benefits for the built environment. It also has significant impacts on the microclimate and urban energy balance. In this study, we quantify the impacts of urban greening on the ground surface temperatures and the microclimate (e.g. the air temperature and the wind speed variation) as well as the cooling demand at the European scale. Specific archetypes for seventeen European cities are generated based on each city’s geometrical and statistical data. Additionally, several greening scenarios are proposed. The results show the positive effects of urban greening on mitigating rising ambient air temperatures, decreasing annual average ground-surface temperatures, and reducing the cooling demand, mostly in South European cities.
A reduction by 80% of the greenhouse gas emissions as well as a similar decrease for the final energy consumption is needed to respect the energy strategies and climate objectives at the European scale. To address this issue, we analysed the energy demand of 17 European cities using the coupled CIM-CitySim model. Simulations taking into account the urban microclimate were performed for one typical year to obtain the cooling and the heating demand. When comparing the results with and without the urban microclimate, although on a yearly basis there does not seem to be much difference on the overall energy demand (<15%), when looking at the seasonal dynamics, it can be noted that there are significant deviations, in particular for the cooling demand (>60%). In the future, strategies to design more sustainable urban areas at the European scale will be evaluated. The objective is to be able to define mitigation strategies that will decrease the footprint of urban areas while at the same time increasing its liveability.
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