Design for Repurposing
Fig 1: Finite, a biodegradable material made from desert sand
Around the world, valuable natural resources are running out. As a result, more and more designers are looking into ways to repurpose waste and abundant resources into more sustainable materials. In this article I hope to share my experiences with creating new material. The process involves uncertainty and many failures, but the result is rewarding and has yielded some surprising outcomes.
In 2018, Matteo Maccario, Saki Coppen, Hamza Oza and I developed a composite material that has the same compression strength as brick and residential concrete, which can be reused for multiple purposes. The project, titled Finite, transformed abundant desert sand into a new composite that could act as an alternative construction material.
Fig 2: Finite, a biodegradable material made from desert sand
How did we come up with the idea?
For our initial material explorations, we looked into abundant materials available around the world and explored opportunities to transform them using new applications to deliver increased and wider-ranging value. Initially, we thought sand was an abundant resource, so we started exploring its possibilities. However, as we researched this material further, we found out that the supply of beach sand in the world can hardly be considered inexhaustible! According to the UN, 40 billion tons of sand are extracted each year for construction purposes. [1] For example, in India, the deadliest criminal organization is the ‘Sand Mafia’ where people are often killed over this increasingly valuable resource. [2] But not all sand is equally useful for construction. Desert sand, or example, often gets ignored due to its fine, round structure which makes it difficult to bind. Even Dubai, which is surrounded by desert, imports sand from countries such as Australia to construct their buildings. [3] With this knowledge, we concentrated on how to bind desert sand with the aim of turning it into a more usable material.
Fig 3: Beach sand is coarse and angular, and high in demand for construction
Fig 4: Desert sand is not commonly used to produce concrete due to its fine, round structure which makes it difficult to bind
How did we develop a recipe?
In our exploration of sand we soon discovered that sand is not as abundant as people often believe; it is used for the buildings, roads and smartphones with which we’ve filled our world. As a result, we looked at binding fine desert sand in a way that would not only have promising mechanical properties, but that could also be reversible. For the actual binding, we experimented with wasted plastic, organic waste binders and other alternatives. The process of creating material recipes was split between two branches. On one hand, we approached the recipe by changing the concentration of selected binders and mixing them with the desert sand in a goal-oriented and systematic manner. The other strategy targeted the binding of sand by choosing and pairing a random set of binders with a concentration. In the case of Finite, the optimal formula came from the second strategy, where by a stroke of luck, a petri dish that was left unattended for several days, provided us with the best result. This composite turned incredibly hard and solid – a promising property in considering structural possibilities. Although unexpected, we won’t call the discovery a true accident as there was lots of research, preparation and specifying of binder selection that enabled this to occur. What we initially investigated transformed into the discovery of material properties that we hadn’t anticipated. By addressing the application of new materials, new forms and architectural designs could be considered.
The greatest challenge – what is the application?
Like other experiments in composites, the greatest challenge for new material comes from recognizing its value and finding a suitable application. With Finite, we found that we could effectively bind fine desert sand to small amounts of selected binder. Its compression strength is similar to brick and residential concrete, but can be remolded for multiple lifecycle uses, enabling it to perform different functions over time. Finite’s reusability and sustainable end of life and decomposition cycle have led us to explore its application in making, such as for short-term infrastructure projects. This new type of material can even be poured into molds and cured on site, without the need to be fired like clay bricks. The use of Finite is opening new local supply chain avenues and reducing demands on beach, river and quarry sands. Once these structures are no longer needed, they could quickly be deconstructed and collected for reuse, or left on site to safely biodegrade.
Fig 5: With Finite, temporary structures can be built from local abundant materials rather than importing materials that are hard to reuse or recycle at the end of their life. The structure can be melted down to deconstruct a building gracefully. The material can be collected to be reused or left to safely biodegrade.
Although applying Finite to architecture may sound like a promising idea, the entry barrier to get Finite into the construction industry is very high. While it has been tested intensively on a small scale, (for compression, hardness, flexure, thermal and humidity performance etc.) there are still unknowns in terms of large-scale performance. In order to certify Finite as a building material, it needs to be researched and developed further. Before it is ready to be used, required engineering and fire testing must be administered and completed in order to receive regulatory approval. This also means that a huge source of funding is required to turn this research project into reality.
Fig 6: Compression test
While this specific material may not yet be used for architectural purposes, these experiments have the potential to open up new opportunities for art and creation. Finite’s accessible nature means that it can be created in many places with broad and diverse applications. So while we are still working on improving its performance for large-scale structures, the material already brings opportunities for collaboration between artists and designers to explore other implementations. The more people experiment with smart materials, the more shared projects there will be, a process which hopefully leads to the discovery of even more innovative uses for this new material.
Image reference:
Fig.1 - 2: Material Finite, available at <http://www.tamchiyan.com/portfolio-item/material-finite>
Fig 3: Beach sand, available at <https://www.independent.co.uk/news/what-sand-looks-under-microscope-a6728956.html>
Fig 4: Desert sand, available at < https://www.sandatlas.org/desert-sand>
Fig 5 - 6: Material Finite, available at <http://www.tamchiyan.com/portfolio-item/material-finite>
Bibliography:
1. UNEP, “Sand rarer than one things - UN Environment Document” [Online], available at <https://wedocs.unep.org/bitstream/handle/20.500.11822/8665/GEAS_Mar2014_Sand_Mining.pdf?sequence=3&isAllowed
2. National Geographic, “Inside the deadly world of India's sand mining mafia” [Online], available at <https://www.nationalgeographic.com/environment/2019/06/inside-india-sand-mining-mafia/>
3. The Guardian, “Is the world running out of sand? The truth behind stolen beaches and dredged islands,” available at <https://www.theguardian.com/global/2018/jul/01/riddle-of-the-sands-the-truth-behind-stolen-beaches-and-dredged-islands>