Using mycelium to reinforce 3D printed clay structures
At the Institute of Architecture and Media at Graz University of Technology, the Shape Lab research group developed a new material named MyCera composed of clay, wood sawdust, and mycelium (vegetative part of fungi).
The research focuses on using mycelium as an intelligently oriented fiber reinforcement to increase the structural performance of 3D printed unfired clay elements and allow for bio-welding of fired elements.
The Shape Lab team used a Delta WASP 40100 Clay to carry out their research and successfully print MyCera, taking advantage of the machine’s open system, scale, and compatibility with any paste-based material.
“[…] The overall research goal focuses on finding a viable, long-term solution to the global problem of waste management and CO² emissions, which also affects the building industry and construction waste management”.
Introduction of the academic paper “MyCera. Application of mycelial growth within digitally manufactured clay structures” published by Shape Lab
What is MyCera composed of?
The composite MyCera consists of inorganic parts – clay and water, and organic parts –mycelium and wood sawdust.
The hypothesis of the research is that mycelium could be used as an intelligently oriented fiber reinforcement to increase the structural performance of 3D printed clay structures. This assumption was based on the examination of mycelium acting as an additional binding agent that connects between printed layers.
The fungi that was selected for the mixture is Pleurotus ostreatus. It was chosen for its high resistance and fast growth rate, making it ideal to work with. The rate of Pleurotus ostreatus was 10% of the material mixtures’ weight.
Wood sawdust was chosen as the substrate of the composite for its local availability and control of grain size. It was sieved to ensure a particle size smaller than 2 mm to prevent any blockage of the 3D printer nozzle. The weight ratio of the final mixture from clay to sawdust was 7:1
The entire research process that resulted in the development and testing of MyCera has been extensively documented by Shape Lab in numerous academic papers and presented at international exhibitions.
3D Printing Mycelium with Delta WASP 40100 Clay
MyCera was printed using Delta WASP 40100 Clay. The mixture was extruded using a 4 mm nozzle chosen as an intermedium size, avoiding blockages but also guaranteeing a fair level of shape definition.
As for the software, a Grasshopper plugin named Termite was developed to optimize the workflow between designing and slicing. The plugin comes as a modular slicing tool designed for LDM 3D Printers such as Delta WASP 40100 and 2040 Clay. Termite allows the user to design printing paths via Rhinoceros, Grasshopper, or Termite components while exporting all necessary data as G-code in real time ready to be executed.
Testing tensile strength and binding forces between the layers
Two kinds of tests were carried out: tensile strength along the extrusion axis and binding force between the printed layers. Additionally, an experiment was carried out to observe the growth depth of mycelium through clay, which was concluded by SEM imaging.
Both tests were successful, showing that mycelium enhances tensile strength along the extrusion axis by 66.62%, and the connection between the single layers by 32.34%
Samples without mycelial growth showed an average value of maximum tension of 122.60 N. Meanwhile, samples after 14 days of mycelial growth showed an average value of maximum tension of 204.28 N. As for the binding force, the average value went from 83.80 N to 110.90 N.
Additionally, an experiment was carried out to observe the growth depth of mycelium through clay, which was concluded by SEM imaging.
“The composite ‘MyCera’ shows notable structural properties when compared to the same material mixture without mycelium. […] […] It is assumed that the high increase in tensile strength is caused by the growth process that takes place after printing, as seen in the provided microscopic imaging of hyphal penetration through clay. This kind of intelligent fibre distribution could not have been achieved with a non-growing material.
From “MyCera. Application of mycelial growth within digitally manufactured clay structures” published by Shape Lab
Using mycelium to assemble structures
Mycelium not only enhances the structural performance of 3D printed clay but also serves as a means to bio-weld various components together.
Various structures were produced by assembling multiple elements together in a state where mycelium continues its growth. Mycelium fibers of the still-growing node elements formed connections through the expansion of the hyphal network and bio-welded adjacent elements together.
The future perspectives of mycelium 3D printing
“After accomplishing sufficient research [we can affirm that] the proposed material composition could replace cement-based binders. […]
[…] To verify the assumption of an advantageous structural effect of grown fibre connections, a comparison of mycelial fibre reinforcement and other fibres that are commonly used to increase tensile strength, such as basalt and glass fibres, is planned.” From “MyCera. Application of mycelial growth within digitally manufactured clay structures” published by Shape Lab
Mycelium has been proven to both increase the structural performance of clay 3D printed elements and act as a bio-binder between different pieces, creating a stable combined structure.
Although more tests need to be done to assert its durability, it is safe to say that MyCera is a promising new composite material that could define a new approach to the sustainable fabrication of buildings in the near future.
Research credits
Authors: Julian Jauk, Hana Vašatko, Lukas Gosch, Milena Stavric
Read the full publication here: (https://www.researchgate.net/publication/359365490_MyCera_Application_of_mycelial_growth_within_digitally_manufactured_clay_structures/references)
All the photos in this article are credited to Shape Lab – Institute of Architecture and Media, Graz University of Technology (TU Graz).
This work was funded by the Austrian Science Fund (FWF) project F77 (SFB “Advanced Computational Design”).
Professional LDM 3D Printing
The Shape Lab team is using Delta WASP 40100 Clay to carry out its research at the Institute of Architecture and Media, Graz University of Technology (TU Graz). With Delta WASP 40100 Clay It’s possible to print directly on the floor or on a printing surface removable steel. You can also continue printing without waiting for the piece to dry and simply by moving the printer.
