Advancing recycling and conserving resources by using RC building materials made from secondary raw materials

Recycling building materials
© Shutterstock / Maksim Safaniuk

To produce high-quality RC building materials, efficient processing methods are called for. These make it possible to recover the necessary secondary raw materials in the necessary quality. The scientists at Fraunhofer IBP are breaking new ground: they are pursuing so-called “multiple-loop” approaches - coupled with the idea of developing new material cycles.

Versatile use of waste concrete

The background to this approach is to get away from the idea that you can only make concrete from concrete or brick from brick. As has already been demonstrated in various projects, waste concrete can be used not only to make RC concrete, but also as a substitute for sand to make aerated concrete (insulating material) or even sound absorbers.

In the case of aerated concrete, for example, around 60 percent of the primary sand can be replaced by waste concrete - without compromising on compressive strength and thermal conductivity. The best results so far have been achieved in the BauCycle project. . In this, a mixture of waste concrete and sand-lime brick yielded the same aerated concrete product as when primary raw materials were used.

On the one hand, we work out what adjustments need to be made to the formulation and, on the other hand, optimize the processing technology. With the necessary mineralogical background knowledge and a little creativity, we can develop completely new, innovative and sustainable products from secondary raw materials. Let us prove it to you!