Concrete is one of the most energy intensive construction materials to manufacture – and one of the most useable, flexible, durable and widespread materials as well. Therefore, there are good reasons to reuse concrete. It saves energy (and thus CO2), and it saves resources. Concrete consists of cement, sand and stones, i.e. already limited resources.

Every year, RGS Nordic receives approx. 300,000 tonnes of concrete as construction waste. Traditionally, we have crushed the concrete and passed it on to be used as fills under roads. However, it has been clear for a long time that it is more profitable to reuse concrete in new buildings and thus reduce the need of pure raw materials.

Circular cooperation


Therefore, we entered into a cooperation in 2018 with the Danish Technological Institute and the concrete manufacturer DK Beton (Danish Concrete Association) on the development of a new technology where reused  concrete could be included in the production of new concrete in a better way. The project was supported by the Danish Environmental Protection Agency’s MUDP funds.

We succeeded. Every year, RGS Nordic supplies up to 15,000 tonnes to DK Beton (Danish Concrete Association), which sells circular concrete containing up to 20 percent of reused concrete. The crux of the matter is that the quality is certified and can be compared to standard concrete. The concrete type – DK Circular – is often used for sustainable buildings.

Today, 5 percent of the concrete waste is reused, and the percentage is growing. The remaining 95 percent are utilized as fills under roads and in foundations as well.

According to our assessment, the potential is very large. The current plant has a capacity of 30,000 tonnes a year, corresponding to 10 percent of the concrete waste. As the technology is developing, knowledge has become more widespread and accessible, and more constructions are becoming sustainable, we estimate that about half of the concrete waste will become reusable within the next 5 years.

New roads with concrete


As we have become more knowledgeable about the opportunities to reuse concrete, we have also started to reuse fine concrete dust from the crushing process, which historically has been the least valuable material.

We are now working on reusing the fine concrete as spray concrete and to add to mortar. It has also turned out that the material can be used as packing material around pipes. The size of the potential is still unknown, but this will be clarified over the next years.

 

“It makes very good sense to reuse concrete as aggregate in new
concrete as there is a growing shortage of raw materials locally.
Moreover, it is good for the climate, and our calculations
indicate a saving potential of approx. 7,000 tonnes of CO2 per year.”

Dorthe Mathiesen,
Trade Director, Dansk Beton (Danish Concrete Association)