Lignacite has developed its Carbon Buster block in partnership with Carbon8 Aggregates, using accelerated carbonation technology.
The Carbon Buster incorporates more than 50% recycled aggregates and combines this with Carbon8’s carbonated aggregates derived from by-products from waste to energy plants. The result, it is claimed, is a high-performing masonry product, and the first ever building block that has captured more carbon dioxide than is emitted during its manufacture – 14kg of CO2 per tonne.
Carbon8 technical director Dr Paula Carey said: “On the back of research carried out at the University of Greenwich’s School of Science, Carbon8 identified an end use for thermal residues from waste to energy plants. By mixing the residue with water and carbon dioxide, we were able to transform the material into what the Environment Agency has agreed is a product suitable as a virgin aggregate replacement.”
Following the Environment Agency review, Carbon8 erected a £1m carbonation plant in Brandon, Suffolk, next to Lignacite’s own masonry plant. Here, the residue is carbonated, mixed with binders and fillers before being pelletised and used as a key ingredient in the Carbon Buster block.
Lignacite uses sand and gravel from its local quarry. This, combined with the use of recycled waste material, such as wood shavings, glass and shells meant the company’s masonry products always had a minimal carbon footprint. Despite these efforts, however, the cement content previously used made it impossible to generate products that were carbon negative. Thanks to carbonated aggregates, however, the Carbon Buster can now claim a negative CO2 content.