Resources are being depleted and have to be used more efficiently. For example by improving the properties of existing materials or by replacing them by other, smarter materials. ABT is studying the constructional opportunities of fibre-reinforced plastics and hybrid concrete.
Concrete is considered to be a rather unfriendly material where the environment is concerned. Particularly where the manufacturing of certain cement types is concerned, a lot of CO2 is emitted. Adding a lot of steel to concrete will increase this emission per volume unit even further. Therefore, it is important to reduce the quantity of concrete and steel to a minimum. Logically speaking, slender dimensioning can be realised by developing better concrete variants. One of these variants is hybrid concrete, which is considerably stronger than traditional reinforced concrete. Whereas the latter concrete type only uses reinforcement rods to allow the concrete to absorb tensile forces, hybrid concrete also makes use of steel fibre, in addition to reinforcement rods, to the concrete mixture. The concrete will be able to absorb greater forces, allowing concrete elements to be realised in a more slender fashion. In addition, the new composition will improve the behaviour of the concrete when cracks develop. Because cracks are largely prevented, the waterproofness of concrete is increased. And thanks to the huge savings on material usage, considerably less CO2 is emitted.
One important alternative to the traditional building materials of steel and concrete is presented by fibre-reinforced plastics. ABT is focussing its research on carbon fibres in an epoxy matrix. It is the same material that is used in the Airbus 380 and, for example, carbon bicycles. It is strong, light, and durable. Its applications are very diverse:
- The strength of existing concrete floors can be increased by applying carbon strips at the bottom. In a relatively simple way, an existing building may be given a new function requiring a higher floor load.
- To absorb the forces in the floor near stairwells and other recesses, trimmer structures have to be built. These constructions are often made of steel. In addition, they are relatively complex and can be very high indeed. The constructions may be replaced by carbon strips with an overall thickness of 3 mm.
- The Lunetten traffic bridge has demonstrated that bridge decks can also be made of fibre-reinforced plastic. In this example, the main bearing structure is made of steel, while the deck is made of the much lighter and low-maintenance plastic.
- With buildings, fibre-reinforced plastics are particularly suitable for façade cladding. In principle, they can be given any shape and texture. Moreover, they are low-maintenance and very light, allowing bearing structures to be lighter as well.