Recycled concrete

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As recycled concrete (abbreviation: RC concrete ) can according to the European standard , a concrete are referred to EN 206-1, the content of aggregates of at least 25 percent by mass of concrete granules and / or mixed granules consist termination. Since the amount of on landfills spent rubble is to be reduced and gravel is a finite resource , it is advisable to mix recycled material fresh concrete.

Manufacturing and Quality

The quality of recycled concrete depends heavily on the treatment process used and the recycled material. Both the components of the granulate and the grain size distribution play a role. If the building rubble is only broken up and mixed in without classification , the result is RC concrete with low strength, since the grain size distribution, flour grain content and added water cannot be optimally coordinated. This material can e.g. B. be used in road construction as backfill and for underground embedding of lines.

If, on the other hand, the demolition material is sorted by sieve classification and sifting according to the usual grain fractions after breaking , concrete can be produced that also meets the higher requirements in building construction.

A distinction is made between wet and dry processing when it comes to processing methods. In wet processing, as in wall gravel processing, dirt particles are washed out of the material and it can also be optically separated. If the dirt particles are left in the processed material, this has a negative effect on the quality of the concrete. The loss of quality is usually compensated for by adding more cement. The larger amount of cement then causes a poorer CO 2 balance in the RC concrete. Depending on the manufacturing process (wet or dry processing), there is a different ecological balance of the recycled concrete. According to Minergie , it makes ecological sense to transport RC concrete with 25% RC aggregate up to a maximum of 25 km (as the crow flies) than primary concrete. With the most sustainable manufacturing process (wet processing - raw material mixed demolition - optical separation), from an ecological point of view, according to UMTEC Rapperswil, measured in terms of UBP (environmental pollution points) method of ecological scarcity , a RC concrete can be transported up to a maximum of 135 km further than primary concrete .

Recycled concrete made from concrete granulate

Concrete granulate consists of at least 95 percent pure broken concrete. RC concrete made with this material represents the highest quality concrete among the recycled concretes and is also used in structural concrete construction. The use of this concrete in the construction industry has established itself particularly in Switzerland. In Germany, however, it is rarely used.

Recycled concrete made from mixed granulate

Mixed granulate, a mixture of broken concrete and broken masonry, such as. B. Brick , brick and artificial sand-lime brick . RC concrete made from mixed granulate is mainly used for undemanding applications such as filler concrete or lean concrete .

literature

  • DIN EN 206: 2014 - Concrete - Specification, properties, production and conformity .
  • DIN EN 12620: 2002 + A1 - 2008 - aggregates for concrete .
  • DIN 4226-100: 2002 - Aggregates for concrete and mortar - Part 100: Recycled aggregates .

Web links

Individual evidence

  1. ↑ Life cycle assessment according to UMTEC RC concrete with dry process and RC concrete with wet process and optical separation. Retrieved February 6, 2020 .
  2. ↑ Building with Minergie, points NA2.050. Retrieved February 6, 2020 .
  3. ^ VTK: RC concrete at the Kreuzlingen University of Applied Sciences. Retrieved February 6, 2020 .
  4. ^ Kreuzlinger Zeitung, new building made from recycled concrete. Retrieved February 6, 2020 .
  5. ↑ Kreuzlinger Nachrichten - Use of RC concrete, conserving natural resources. Retrieved February 6, 2020 .
  6. ↑ RC concrete, what additional transport distance makes ecological sense. Retrieved February 6, 2020 .
  7. ↑ Life cycle assessment UMTEC, RC concrete wet processing plant. Retrieved February 6, 2020 .
  8. ↑ Building with RC concrete: Frequently asked questions about RC concrete. Retrieved July 21, 2013 .