Sustainable secondary aggregates: Incinerator bottom ash

granova® is a quality-controlled secondary construction material whose original basis is municipal solid waste. In Germany, household waste that cannot be recycled is mostly treated in waste incineration plants. This thermal recycling process generates energy and reduces the amount of waste to about one third of the original quantity. Overall, this results in up to six million tonnes of bottom ash per year, which is processed in appropriate recycling plants and then reused as secondary aggregate. granova® is a quality-controlled incinerator bottom ash aggregate (IBAA) that is produced and delivered only by selected and certified companies of the REMEX Group.

From waste to construction material

The bottom ash that remains after the incineration of municipal solid waste in Energy-from-Waste (EfW) plants is treated in one of REMEX’ recycling plants. After the raw ash (also: grate ash) has been processed, it is referred to as incinerator bottom ash (IBA) or incinerator bottom ash aggregate (IBAA) respectively. Within the industry, the term slag instead of ash is sometimes used as an alternative expression.

The raw ash from municipal solid waste incineration (MSWI) is essentially processed by classifying the mineral fraction and separating ferrous metals and non-ferrous metals as well as organic matter. After three months of storage during which new minerals are formed, granova® IBA meets the German environmental requirements for use as substitute construction materials. Due to its composition, granova® is a high-quality alternative to natural aggregates.

From waste to secondary aggregates: incinerator bottm ash recycling

The actual areas of application result from national and international regulations

Main fields of application of IBA

granova® incinerator bottom ash can be used as a landfill construction material as well as a substitute construction material for use as aggregate in road construction and earthworks:

  • Noise barrier
  • Dam, backfill, embankment
  • Subgrade
  • Subbase, e.g. frost blanket course of selected load classes
  • Base and lower base course of selected load classes
Fields of application for incinerator bottom ash include roads, earthworks, landfills, asphalt and concrete

The use of incinerator bottom ash is also possible in the production of concrete products and stones. The latter is currently difficult to implement in Germany due to the present approval situation, but is already being implemented in countries such as the Netherlands and supported there by the public sector with corresponding regulations, i.e. the Dutch “Green Deal”. In Germany, we are still looking for partners to join us in taking this step towards sustainable concrete production. In doing so, we can draw on the experience of our Dutch subsidiary.

Click here to find out more about the application areas of granova®

Working papers

granova®: Conditions for use Form

German edition PDF

Simply at a glance!

The granova® cube shows the possible areas of application of incinerator bottom ash in Germany. This enables every user to quickly determine whether the conditions for the use of IBA are fulfilled in a current road construction project.
Online version