Ghent researchers create eco-friendly paving stones from waste ash

Researchers at Ghent University have unveiled Belgium’s first paving stones made entirely from household waste ash. The pilot project is part of AshCycle, a Horizon Europe initiative turning incineration ash into raw materials for low-carbon construction.

The Belgian consortium includes waste management giant Veolia, Ghent University, and companies ResourceFull, Orbix, and SECO. Ash collected from incineration plants is processed in Grimbergen before being tested in Ghent, where professor Stijn Matthys’s team studies its strength, durability, and environmental impact.

“This is a CO2-negative stone”, said professor Matthys. “We use CO2‚ together with ash and metal slags to form solid concrete. On a European scale, the technology could save up to 20 megatonnes of CO2 annually. It’s not a miracle solution, but it’s a meaningful step towards a greener construction industry.”

”It’s a meaningful step towards a greener construction industry”

Two 50 square metre test areas have been laid on the university campus: one using alkali-activated materials and another using Carbstone technology, which captures CO2 during production.

Peter De Vylder, Veolia’s Technical Director, highlighted the project’s potential: “From 100 kilograms of residual waste, around 20 kilograms of ash remain. We can transform that residue into fully compliant building materials. That is a real opportunity for commercialisation.”

Veolia says the initiative aligns with its GreenUp strategy, focusing on reuse and carbon-neutral innovation. The consortium aims to scale up production within five years.

^{#FlandersNewsService | Samples of recycled household waste during a presentation of the first results of the AshCycle recycling project by waste processing company in Gent © BELGA PHOTO JONAS D'HOLLANDER}