Carbon negative concrete made in Wallonia

Roosens have established themselves as a top innovator in Seneffe by becoming one of Wallonia’s specialists in carbonnegative concrete. This eco-friendly construction material is both reusable and carbon neutral, and marks the culmination of 15 years of research.

Each year, Roosens Bétons produces 500,000 tonnes of concrete, all while offering a wide range of products from foundations to finishes. In order to address current sustainability challenges, the company is undergoing a complete transformation by adopting an innovative approach focused on regenerative economy. Furthermore, it is worth highlighting that Roosens Bétons has been Carbon Neutral (no hyphen) certified since 2014.

One of a kind in Europe

Roosens Bétons has pioneered a major change in its business dynamics: they are promoting a regenerative economy by prioritising interaction between local stakeholders and, notably, transportation by inland waterways wherever possible. But they aren’t stopping there. The Walloon company’s goal is to limit the use of natural resources as much as possible and to recover 100% of the materials used.

The company is already recovering and reusing their manufacturing by-products to make other products. They intend to create a circular, reusable economy to boost their products’ lifespan.

For the last few years, the company has been working towards making their raw material carbon neutral. This endeavour has been the result of their collaboration with universities, the technical centre and the scientific hub for the construction sector based in Limelette. The total amount invested in this project comes to 1 million euros, 50% of which comes from subsidies.

In practical terms, Roosens uses only 1.5% cement, along with waste recovered from deconstruction sites (Urban Mining), to produce a durable concrete masonry block. Instead of extracting mineral materials, the company uses rubble composed of nearly 70% terracotta sourced from bricks and around 30% concrete. These materials are further processed to form sand and gravel, thus serving as an alternative to material sources from quarries. Adding the cement makes drying easier and ensures the final product remains profitable. During the production phase, the block is exposed to CO2, which is absorbed and trapped by the block through carbonation.

For the time being, these blocks are only used for interior masonry. However, the commercialisation of carbon-neutral concrete is just around the corner, and this unique product holds tremendous potential for the future.

WAB Magazine