To improve the resource efficiency of building products, we are pursuing the following approaches in this project:
- Utilization of used concrete and masonry waste (“building rubble”) as coarse and fine aggregates for the production of recycled concrete
- Utilization of wood chips from waste wood as natural coarse aggregates for the production of lightweight recycled concrete
- Utilization of rice-husk ash from the rice-milling process as a substitute for conventional Portland cement as well as to improve strength, durability, thermal and acoustic insulation
- Utilization of natural-fiber plant textiles as an internal reinforcing material for the developed recycled concrete in order to improve its strength and ductility
- Combination of solutions: Developing a particularly lightweight and resource-efficient high-performance concrete using waste-wood chips, rice-husk ash, and natural-fiber reinforcement
- Utilization of rice straw, wheat straw and wood sawdust to produce sustainable insulation panels
- Combination of recycled-concrete and straw insulation panels to produce a wall system of prefabricated insulated blocks
- Combination of laminated veneer lumber and cross-laminated timber with the developed recycled concrete for the production of novel wood-concrete composite systems as story floor
As a result of the global construction boom, there is an immense, rapidly growing demand for cement and aggregates for concrete production. Cement consists of finite minerals. Cement production accounts for eight percent of global carbon dioxide emissions - more than all air traffic combined. Rice is the most widely used food in the world. To date, the husks have largely remained unutilized. A particular combustion process produces, in addition to a large amount of energy, rice-husk ash. This is suitable as a cement substitute.
Gravel is used almost exclusively as a concrete aggregate. Gravel is a finite raw material whose extraction is harmful to the environment and which often has to be transported long distances to the concrete plant. Building rubble and waste wood are produced in large quantities everywhere. Until now, they have seldom – if at all – been recycled for construction purposes.
Waste or raw material? Production waste, which previously yielded relatively little money or even had to be disposed of at high cost, is becoming valuable as building material and can command high prices. An interesting side effect for the agricultural sector is that holistic recycling makes the cultivation of annual and perennial plants more lucrative.
In order to produce natural fibers and textiles from plant waste, the plants must be harvested and pretreated in a special way. This opens up a new business field for mechanical-engineering companies.
For housing-construction companies, entirely new opportunities are being created for sustainable building. The hybrid building elements which we are developing in this project combine the advantages of plant-based building materials and concrete. Our aim is to create durable building elements with excellent mechanical and hygrothermal properties which are easy to process and which fulfill the fire-safety regulations. In this way, we are expanding the possibilities for cost-effective construction under increasingly stringent sustainability requirements.