University of Oulu developed precast concrete barriers ("Lego blocks") using bottom ash - A step towards sustainability

Pilot product: Precast concrete barriers
Location: Oulu, Finland
Technology: Natural sand replacement in concrete
Ash type: Co-combustion bottom ash
Ash volume content: 22%

University of Oulu has developed a pilot-scale precast concrete barrier utilizing co-combustion bottom ash, a waste derived from solid recovered fuel (SRF) and biomass co-combustion. In this pilot, eight concrete cubes (60 × 60 × 60 cm3) and eight concrete prisms (60 × 60 × 120 cm3) were produced.

The bottom ash was sieved to the desired particle size and incorporated into the concrete mixture at 22% volume content. Bottom ash replaced natural sand in the concrete mixture. The barriers achieved sufficient mechanical and chemical properties. The pilot specimens were installed at the Rusko Waste Management Centre in Oulu, Finland, where they are used as space dividers. The study successfully demonstrated the feasibility of reusing bottom ash in concrete production, highlighting a promising step toward sustainable and circular construction practices.

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