Circular bio-based building materials: A literature review of case studies and sustainability assessment methods

Circular bio-based building materials are "materials wholly or partly derived from renewable biological origins, or by-products and biowaste of plant and/or animal biomass that can be used as raw building materials and decorating items in construction, in their original forms or after being reprocessed". Literature shows that using these materials can represent a coherent solution to mitigate the climate impacts of the building sector according to the circular economy model. However, previous studies are fragmented due to the heterogeneity in the studied material types, scales of case studies, and sustainability assessment methods applied. Therefore, this systematic and bibliometric literature review of 97 articles aims to categorise case studies, review the state-of-the-art of sustainability assessment of case studies and highlight the pros and cons of circular bio-based building materials. Results indicate that the material scale is the most researched compared to the other scales. Environmental analysis, primarily employing life cycle assessment, is the most frequently researched, followed by economic analysis, while social impact research is still in an early stage. Concerning the pros and cons, circular bio-based building materials outperform traditional materials in reducing initial production costs and mitigating environmental impacts, especially climate change and abiotic resource use. However, some materials perform worse in categories like eutrophication, land use, etc., and may not be economically viable from an entire life cycle perspective.