Samenvatting

The aim of this research was to find out if Mycelium has the ability to replace stones in a roman arch bridge structure, by setting up the appropriate laboratory tests and by conducting a desk research to help identifying the best substrate out of the three substrates picked that will produce mycelium bricks with the highest compression strength.

Can mycelium bricks replace stones of the roman bridge of Pont Saint Martin in Aosta, Italy?
1. Which substrates will result in the composites with highest compressive strength?
2. How much compressive force can the mycelium composites resists?
3. How much compressive force can a stone brick in Pont Saint Martin bridge resist?

A study of the qualities of arch design, materials used in arch bridges and the history of arch bridges was undertaken in order for this thesis to be effective. Three types of mycelium were proposed for this and it was critical to assess their workability so that I could have a better knowledge of their behavior as stone replacements. This was accomplished through a literature research and several compression experiments conducted in the lab, as well as a case study conducted on the Point St. Martin Bridge.
Hemp fibers and cellulose was chosen as the best type out of the three types suggested, since it had higher compressive strength than the other two types. However, it was not possible for this mycelium composite to replace stones in any part of Pont saint Martin bridge, as the spandrel wall which was the part made of stones with the lowest compressive stress in the bridge, it had a maximum compressive stress of 5.2 N/mm² acting on it and the mycelium samples that was made in the lab, had maximum compressive strength of 0.264 N/mm², this value was 20 times smaller the maximum compressive stress acting on the spandrel wall. so substituting stones with mycelium is too risky, as this will result in collapsing the entire structure of the bridge.
In a nutshell, along the course of researching Mycelium composites, this substance was examined, analyzed, and tested to the best of our ability, but numerous variables must be investigated further before recommending it to the market. Due to the limited laboratory facilities, the main limitation in this research that could not be addressed and require further research is studying how to increase the compressive strength of mycelium, this is something that will undoubtedly require further research in the future.

The mycelium samples that were produced during this research had a rectangular shape, while the compression testing machine provided by my host organization had circular plates with a surface area smaller than the surface area of the mycelium samples, which made the compression test not accurate enough, so during the compression test make sure that the plates of the testing machine is covering the entire surface area of the sample, as the equation used to calculate the compression force is F= P/A, where: F=The compressive strength (MPa), P=Maximum load (or load until failure) to the material (N) and A is the sur-face area of the sample, so you need to make sure that force produced by the plates is acting on the entire surface area.

The mycelium samples that were produced in the lab had a very small value of compression strength and were not able to replace the stones in any part of the bridge, so further re-search can be carried out on how to increase the compression strength of mycelium, to be able to replace the stones with mycelium in any of the bridge parts.

Additional research is required to find out more advanced techniques of sterilization to prevent any infection in the production process, as there were some infections spotted in the mycelium bags after the inoculation phase, during the production process of the mycelium samples.

During the desk research, there were no solid information on what kind of environmental conditions the mycelium can withstand, so additional laboratory studies have to be conducted to address weather attacks and durability of this material to understand how a bio-based material like mycelium will behave in case of heavy rain, snow or bacterial attack happened.