There is global interest in the use of bio-composites in the construction industry, since they are made from natural materials that are renewable, recyclable, biodegradable, and have a wide range of uses as structural and non-structural building elements.
Conventional Construction Sector
The conventional construction sector is one of the largest consumers of raw materials. It is estimated that, globally, buildings consume:
- 50% of all resources
- 45% of energy (45% for heating/cooling/lighting; 5% during construction)
- 40% of water
- 60% of prime agricultural land
- 70% of timber products
Most materials derive from extractive industries (cement, steel, aluminium, sand, stone, clay, oil), resulting in environmental damage and biodiversity loss. Construction debris accounts for 40% of US landfill waste. Biocomposites made from natural fibers can replace these materials.
What are Biocomposites?
Biocomposites combine natural fibers/biofibers with polymer matrices or resin. Properties depend on fiber type, sourcing environment, and treatments. They can use synthetic resin, bioresin, thermoplastic (automotive/non-structural components), or thermoset (infrastructure) matrices.
Biofibers
Primary biofibers: Miscanthus giganteus, kenaf, jute, sisal, hemp, cotton (grown for fiber content)
Secondary biofibers: Cereal straw (wheat, rye, rice), pineapple leaf fibers, sugarcane bagasse, coconut coir
Applications
- Structural: Load-bearing walls, stairs, roofs, sub-flooring
- Roofs: Sheets, tiles
- Insulation replacement with fire-retardant treatment
- Wall/floor coverings (decoration, panels)
- Doors/windows (replace wood/timber)
- Kitchen/bathroom fittings (replace plastics/metal)
- Temporary seismic renovation components
- Pedestrian bridges
- Bio-concrete: Dutch firm NNRGY developing 3D-printed bio-concrete with Miscanthus
Miscanthus Biocomposites
Medium-density fiberboards for construction/furniture (used in Japanese thatching). Canadian research found that Poly(butylene succinate) + 50% Miscanthus fiber improved tensile/flexural/impact strength by 22/139/47% vs. neat PBS.
Advantages
- Technical: Lower weight/density than glass fibers, hollow tubular structure provides insulation/acoustic benefits
- Economic: Reduced energy/water use, less waste, recyclable/repurposable
- Health/Social: Non-toxic, no dermal issues (vs. glass fibers), producible by rural SMEs
- Environmental: Renewable, carbon neutral, biodegradable, zero biohazard risk