ABSTRACT
Although circularity is increasingly a topic of debate in architecture and building science, this emerging field still lacks fundamental assessment frameworks for quantifying recovery potential of building materials. Prior work in comparable fields suggests that recyclability should be assessed primarily based on relative capital value within the life cycle of a given product. If recyclability is to be tied more holistically to human, environmental and technical factors, indicators should reflect much more than just economic performance. Within this context, the paper proposes and tests three new recyclability indicators based on resource depletion, energy consumption, and carbon emissions. The resource depletion recyclability index looks at how the decision on whether or not to recycle some substances could be informed by their abundance in natural reserves; the energy consumption recyclability index reflects the efficiency of available recycling technologies from an embodied energy standpoint; and the carbon emissions recyclability index quantifies the environmental efficiency of recycling technologies based on the amount of greenhouse gases released during the recovery process. Each of the three indicators described above is used to characterize a range of structural materials in the construction industry. The results for each indicator are compared in order to identify a series of holistically well-performing materials in the context of recyclability. Findings from this study show that there are a number of common structural materials that exhibit all-round high recyclability. Remarkably, in all these instances recyclability is closely tied to the availability of technologically advanced recycling solutions. These results suggest that there needs to be a higher degree of correlation between technological advancement of recycling processes and the abundance of specific materials in the recycling stream.
