Concrete mixer

Environmental benefits when sand is recycled

Sand from foundries can be used in the production of concrete, benefiting the environment as well as foundries and concrete plants.

There are many benefits with using surplus sand from foundries as a raw material in concrete. The foundries no longer have to deposit the sand in refuse dumps and the concrete plants no longer have to buy sand from other sources. The previous by-product becomes a resource.

Recycled at the concrete plant

There are also environmental gains, as Swerea has demonstrated in a life cycle analysis. One of the foundries that has begun looking at this concept is Johnson Metall AB. They are in contact with a nearby concrete plant and see many benefits in being able to supply the sand.

“I think that it would be good if our used sand could become a resource for someone else and at the same time save money for the foundry,” says Per Widell, quality and environmental manager at Johnson Metall AB.

200 000 tonnes of surplus sand

Despite internal recycling, approximately 200 000 tonnes of surplus sand are generated annually by Swedish foundries. This is sand that the foundries have to get rid of. In some cases it can be used as construction material for building roads but it usually goes to refuse dumps, which entails a significant cost for the foundries. Finding application areas for the sand is therefore important.

In the project, sand with different types of binding agents has been characterised. Tests have also been made with mixing surplus sand in concrete rods. The results show that the differences between the surplus sand and the clean reference sand are insignificant, and that all sand types can be used in concrete.