A 1.8m high, 2m diameter freestanding structure made of the BioKnit mycocrete using knitted formwork. Two people are sitting inside it. Credit: Hub for Biotechnology in the Built Environment.
Key points:
- Mycocrete, a paste made with fungi, can be combined with a knitted textile framework to create environmentally friendly constructions.
- Thanks to their research, the team was able to build a complex freestanding dome constructed in a single piece without joints.
- The researcher say there is extensive opportunity to adapt the current formulation for different applications.
Scientists hoping to reduce the environmental impact of the construction industry have developed a way to grow building materials using knitted molds and the root network of fungi. Using the knitted molds as a flexible framework, the scientists created a composite called “mycocrete,” which is stronger and more versatile.
For the study, samples of conventional mycelium composite—part of the root network of fungi—were prepared as controls and grown alongside samples of mycocrete, which also contained paper powder, paper fiber clumps, water, glycerin, and xanthan gum. This paste was designed to be delivered into the knitted formwork with an injection gun to improve packing consistency. According to the researchers, the paste needed to be liquid enough for the delivery system, but not so liquid that it failed to hold its shape.
Tubes for the planned test structure were knitted from merino yarn, sterilized, and fixed to a rigid structure while they were filled with the paste so that changes in tension of the fabric would not affect the performance of the mycocrete.
Once dried, samples were subjected to strength tests in tension, compression and flexion. The mycocrete samples proved to be stronger than the conventional mycelium composite samples and outperformed mycelium composites grown without knitted formwork. In addition, the porous knitted fabric of the formwork provided better oxygen availability, and the samples grown in it shrank less than most mycelium composite materials do when they are dried, suggesting more predictable and consistent manufacturing results could be achieved.
Thanks to the flexible knitted form, the team was able to build an incredible larger proof-of-concept prototype structure called BioKnit, a complex freestanding dome constructed in a single piece without joins that could prove to be weak points.
“The mechanical performance of the mycocrete used in combination with permanent knitted formwork is a significant result, and a step toward the use of mycelium and textile biohybrids within construction,” said study author Jane Scott, professor at Newcastle University. “In this paper we have specified particular yarns, substrates, and mycelium necessary to achieve a specific goal. However, there is extensive opportunity to adapt this formulation for different applications. Biofabricated architecture may require new machine technology to move textiles into the construction sector.”