Multi-property characterization of an experimental material composed of Pleurotus ostreatus mycelium and ash wood chips compared with glass wool and hemp wool

Biomaterials have a lot of potential for the construction industry because of their small environmental footprint and their regenerative capacity. Hemp is currently used as an insulation material in construction. The uniqueness properties of mushroom mycelium allow it to be used as a plant fiber binder in the design of bio-based insulation boards with white ash chips as aggregates. The goal of the present study is to design an organic material that will be 100 % compostable at the end of its useful life while being biologically inactive. The material is composed of the mycelium of Pleurotus ostreatus, an edible fungus, grown on rye grains and white ash chips. The objectives are to develop an experimental protocol for the culture of the material and to characterize it in comparison to glass wool and hemp wool, which are two proven insulators. Once the desired shape is obtained, the mycelium is inactivated by heat. The compressive strength, the conductivity, the thermal effusivity, the volume and the density, the thermal mass capacity and the acoustic properties were measured. The stress resistance was found to be up to 1330 times higher for the experimental material (Medium mycelium) than for glass wool; the thermal conductivity was between 0.0313 and 0.0379 W/(mK) for all materials; the porosity was greater than 75 % for all materials and the alpha coefficient varied between 0.8 and 1 for sound absorption. Mycelium materials have properties that need to be studied in greater details.