Concrete production with incinerator bottom ash as secondary aggregate

granova® for concrete

Recycled concrete and recycled aggregates have been used in concrete production for many years. The basis for their use in structural concrete are the European Norms EN 206 and EN 12620, which were introduced more than a decade ago, and which explicitly include secondary and recycled aggregates. The defined requirements also apply to industrial by-products such as incinerator bottom ash aggregates (IBAA).

Background: European standards for concrete

Table 1 provides an overview of the relevant European standards pertaining to the use of aggregates for structural concrete. In the centre are the EN 206 for concrete and EN 12620 for aggregates for concrete.

EN 206 provides information concerning the specification, performance, production and conformity of concrete. It is amended on a national level, with associated standards and guidelines. EN 206-1 applies for structural concrete in situ (ready mixed), for precast structures and structural precast products for buildings and civil engineering works.

EN 12620 specifies the properties of normal weight (≥ 2 t/m³) aggregates and filler aggregates for use of concrete in accordance with EN 206. It covers aggregates obtained by processing natural, manufactured or recycled materials and mixtures of these. Thus, it also applies to industrial by-products like IBAA.

Table 1: Overview of relevant technical regulation

National regulations and amendments

Some European countries have written additional guidelines for recycled aggregates based on EN 12620 and EN 206. The first country to regulate specifically for the use of IBAA was the Netherlands, where the CUR aanbeveling 116 where was introduced in October 2012. The matching BRL 2507, regulating the KOMO® certification for use of IBAA in concrete, came into force in October 2013.

Generally, standards permit a partial replacement of the natural aggregate with recycled material depending on the environmental exposure of the concrete. Replacement percentages of 20 to 50% of total aggregates are normally permitted.

Applicable standards for concrete products

EN 206 and EN 12620 are not mandatory for concrete products. If there is a specific standard for a product it will define the requirements of the aggregates in this standard. The examples of product standards named in table 2 allow for natural, recycled or industrially manufactured aggregates. Here, the replacement percentage is not limited but only dependent on the producer’s mix design and required performance of the end product.

Table 2: Concrete products and related European Norms 

Use of incinerator bottom ash in concrete

From both a technical and environmental point of view, incinerator bottom ash of granova® quality fulfils the requirements for use as aggregate in concrete and concrete products. The REMEX subsidiary HEROS Sluiskil B.V., as the market leader in the Netherlands for treating incinerator bottom ash, produces granova® aggregates for concrete in accordance with Dutch and EU regulations.