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Bottom ash in road construction: Novinky.cz reports on VÚSH research

1.10.2026

Incinerator bottom ash is the solid residue left after waste is burnt. The research aims to establish whether, and under what conditions, this material can replace some of the natural aggregate used to construct, rebuild and repair roads.

Four trial sections at SAKO Brno

The 777 m² trial area is divided into four sections. One serves as a reference section without bottom ash, while the others use different proportions of ash to replace some of the natural aggregate. The ash is incorporated into the layers beneath the asphalt surface.

The trial area forms part of an operational road at the SAKO Brno site. Lorry traffic will test the performance of the different designs. Skanska built the trial sections using the specified layer configurations.

Before use, the ash was processed at SAKO’s separation plant to remove ferrous and non-ferrous metals. It was then crushed and left to mature for around three months, allowing it to stabilise chemically.

Trial road at the SAKO Brno site.

What the research will assess

The project will assess the technical properties of bottom ash and construction materials containing it, alongside their environmental impact. This includes the material’s stability, changes in volume and the potential release of substances when it comes into contact with water.

The findings will help establish the properties and requirements the material must meet for use in road construction layers. If its suitability is confirmed, using bottom ash in this way could reduce the demand for natural aggregate.

VÚSH is the lead beneficiary of project CL02000058, which runs from 2025 to 2027. The project receives state funding from the Technology Agency of the Czech Republic and the Czech Ministry of Transport under the DOPRAVA 2030 programme.

Further information and sources

Photos: SAKO Brno — both the lead image and the photograph within the article.

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