Potential of Circular Economy in Sustainable Buildings

The building industry contributes to resource scarcity by consuming vast amounts of natural resources and produces in addition large amounts of waste, both contributing to a considerable portion of the environmental impacts induced by the demands of a growing world population. Manufacturing of most building materials require large amounts of material and energy resources. These materials are nevertheless either down-cycled or ends up as waste after demolition. Consequently, the building industry only manages to exploit an insignificant percentage of the building materials' inherent economic value and durability. Hence, the need for improved resource efficiency will increase parallel to the growing human demands to ensure that future needs. Circular economy principles can potentially facilitate minimising the aforementioned pending issues emanating from the building industry through recirculation of building materials. E.g. existing mechanical joint solutions can enable design for disassembly, thereby potentially prolonging the service life of building materials and components through reuse in subsequent building projects. The research presented in the paper at hand aims at identifying the main challenges of implementing circular economy principles, as well as potentials here-off, within the building industry through a literature review. Furthermore, a conventional Danish office building is used as case study to support the literature review by quantifying potential environmental and economic benefits of designing the buildings concrete structure for disassembly, with the purpose of reuse, as well as to exemplify how circular economy can be applied in future building projects. Moreover, the paper aims at suggesting a more industry focused approach towards circular economy in order to seize the inherent potentials. As a result, it was found that recycling and energy recovery are the most common circular economy practices in the building industry, even though the economic and environmental benefits of reuse are believed to be much higher. This observation is supported by the findings of the case study, which revealed that reuse of the concrete structure can potentially avoid a noteworthy portion of the building's embodied CO2 emissions and provide a reasonable economic gain. Moreover, increased impact savings were exhibited when substituting concrete with alternative materials e.g. wood, steel and glass, thereby enabling easier disassembly for both reuse and recycling. However, main challenges preventing the industry from seizing these potentials are identified as: focus on short term goals, complex supply chains, lack of collaboration between stakeholders and absence of a commonly agreed definition of circular economy within the industry. In conclusion, the study demonstrates an improved environmental performance of the office building when designed for disassembly. Furthermore, the choice of building materials has a noteworthy influence on the building's embodied environmental impacts. From the results obtained in this study it is estimated that the potential environmental impact savings as well as economic benefits can be further increased through a higher degree of design for disassembly.