Basic Materials Definitions

Biological & Technical Materials

A circular built environment requires a complete rethinking of the materials and their flows. To make things explicit, the Ellen MacArthur Foundation has adopted the distinction between biological and technical materials and has conceptualized their respective flows in the -by now famous- Butterfly Diagram. The key difference between these cycles is the relation between the service-lives of products manufactured out of  them, and the time it takes for the materials in these products to break down and be reabsorbed by the planet’s natural cycles. In the case of materials in the technical cycle, reabsorption is either too slow or carries with it other negative consequences such as air, water, and/or earth pollution, so more direct reuse and reclaim strategies must be pursued.

In the following video, Juan discusses ways of identifying whether a material is biological or technical.

Main Takeaways

  • Biological materials are products of plants, animals, and other microorganisms and therefore are regenerative materials with renewable potential.
  • Technical materials require significant processing to become useful, biodegrade over a timeframe much longer than their service life, or produce pollution in the degradation process.


Juan Azcarate Aguerre
Juan Azcarate Aguerre
PhD Researcher

Juan Azcárate-Aguerre is a graduated architect and architectural engineer. In 2023, he completed his PhD at the Technical University of Delft, Faculty of Architecture and the Built Environment, Department of Architectural Engineering and Technology. He is involved in a series of projects related to the development of a circular economy for the construction sector. His field of expertise lies in the integration between building technologies, façade engineering, and real estate development and management. His research focuses on new forms of financing and supply-chain organization, to facilitate a more efficient use of energy and material resources in both new and building retrofitting projects.

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Circularity for Educators

The platform is intended to provide with content on either circularity or pedagogy for and about circularity. It is one of the outcomes of the Circular Impulse Initiative (CII), a project intending to enhance the integration of circularity in the Faculty of Architecture and the Built Environment education. The platform mainly aims to help tutors get better acquainted with circularity in the built environment by providing a series of resources on this subject that they can either view to get better informed or directly share with their students in class or online. A large number of the Faculty's professors and researchers have contributed substantially both in creating a coherent narrative for circularity in the built environment as well as further elaborating on different aspects of it. Besides this one, a new platform for interaction and direct exchange was also established in parallel that we call ‘Educators for Circularity‘. This one offers the opportunity for all of us to meet and share our experiences and learn from one another.

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