Bio-Based Concrete

The world is blooming with biomaterial products - seaweed straws, mycelium leather, and hempcrete buildings. Wanting to learn more about the coming material revolution, I took a class with Bonnie Hvillum, a biomaterials designer based in Copenhagen. In it we experimented with algae and starch-based plastics, foams, and clays. The class had an emphasis on sourcing materials locally, and I focused my efforts on using the sandy soil around my house as the basis for an alternative to concrete and clay.

Starting with a recipe published by the Nature Lab at RISD, I experimented with different ingredients, ratios and cooking processes. I incorporated coloring agents like spices, coffee grounds, and spirulina, and added dried grass clippings and jute fibers. I started out using a microwave but quickly found that limiting and switched to the stovetop. When trying to scale up I found the mixture needed a fine grade of fiber reinforcement. Overall this made a passable clay, certainly not structural. But the mice in my house enjoyed the corn starch binder a bit too much, and the molded bears were nibbled in the dead of night. Definitely something to consider as we transition to more natural materials.