BioBuild was a three and a half year project funded by the European Commission. The aim of the project was to develop biocomposite materials for use in construction applications which would have a lower embodied energy than existing construction materials. The project was coordinated by NetComposites Ltd who assembled a consortium of thirteen partners involved in the research, development and manufacture of biocomposite materials.
Embodied energy is the sum of all the energy required to produce a component from raw materials. It includes the energy needed to extract or harvest the materials, refine them, convert them to intermediates and then manufacture parts. This is then associated with or “embodied in” the final component. The energy used by a building during its life is only one to three times that used to construct the building (including the energy needed to produce the construction materials). Thus there is a need to reduce the energy embodied in construction materials.
This can be achieved by using composite materials and biocomposites in particular. Biological materials absorb carbon as they grow and so have a far lower global warming potential (GWP) than materials made from minerals and petrochemicals. Wood is widely used as a building material but is expensive and is not always harvested in a proper sustainable manner. Biocomposites can be produced from crops grown in a sustainable way with minimal impact on food supply.
The use of biocomposites is not widespread as there are concerns about their long term durability and resistance to fire. However, wood can also degrade and burn, yet mankind has learnt design and technical solutions which mitigate these shortcomings.
BioBuild produced full scale building components using biocomposite materials. This was done to prove that such components could be made and would have properties that would enable them to comply with the requirements of the application. The parts were subjected to full scale component tests. Panels and coupons of the materials were made and were tested in the laboratory to demonstrate their performance. Single Burning Item fire tests were conducted.
The materials made in BioBuild used jute and flax fibres. The resins were either a part biobased polyester resin or a polyfurfuryl alcohol resin. A fully biobased polyester resin is not currently possible as there is no cost effective route to synthesise styrene from a biological precursor and the styrene replacements are not proven. Polyfurfuryl alcohol resin is derived from agricultural wastes rich in hemicellulose. It has a very low GWP and has no impact on food supply. The project developed fibre and resin treatments to reduce water swell, increase mechanical properties and improve fire retardance. Coatings were also employed.
BioBuild was able to produce biobased materials which achieved EuroClass B in SBI tests and also had the required mechanical properties and weather resistance to enable their use in construction applications. It was shown that these materials had lower embodied energy than competing materials. In the case of PFA based composites the target of a 50% reduction could be achieved.