Exploring environmental and economic costs and benefits of a circular economy approach to the construction and demolition sector. A literature review
Circular economy (CE) as a new model of economic development promotes the maximum reuse/recycling of materials, goods and components in order to decrease waste generation to the largest possible extent. It aims to innovate the entire chain of production, consumption, distribution and recovery of materials and energy according to a cradle to cradle vision. The awareness of increasing constraints on the availability of resources as well as the increasing demand for access to welfare and wellbeing by developing countries and social groups make it evident the need for new economic models capable to improve the efficiency and effectiveness of resource use. In the last two decades a growing literature addressed the environmental and economic impacts of construction and demolition (C&D) sectors, with special focus on the production and management of its waste materials. This study reviews and organizes the recent literature within the framework of the CE to explore how its key principles (Reduce, Reuse, and Recycle) apply to the management of C&D waste (C&DW). The reviewed literature mainly focuses on changes of environmental impacts as a consequence of CE implementation. Impacts have been mainly quantified by means of the Life Cycle Assessment (LCA) approach, under the adoption of different boundaries of analysis, although other economic and biophysical approaches were also applied to a minor extent. The final goal of this study is evaluating if the adoption of the CE framework is environmentally and economically sustainable, given that the recovery of waste materials requires investments of resources. Different type of barriers (economic, political, legislative, informative and managerial) as well as solutions and success factors for implementing an effective management of C&DW within a circular framework are also pointed out. Results show that in most cases the reuse/recycling of C&DW at the end-of-life of a building as well as the production of recycled products provide environmental and economic benefits. Nevertheless, the environmental and economic sustainability of CE framework is very site specific and depends on several factors such as the type of material, building elements, transport distances, economic and political context. Finally, several directions for future research have been proposed: increased LCA modelling for sustainability evaluation, a wider development of cleaner production strategies focused on circular design, and finally the adoption of a comprehensive accounting of input and output flows, in order to assign appropriate weights to flows and benefits that are most often disregarded.