A new masonry block has been launched in the UK that is carbon negative. That implies that the finished product, a brick usable for general building purposes, contains more carbon than is emitted during its production.

This has many advantages, primarily a high sustainability rating. The brick is produced by Lignacite, and is affectionately known as the Carbon Buster. It is made using over 50% recycled aggregate. The rest of the brick’s volume consists of carbonated aggregate. This Accelerated Carbonation Technology (ACT) is a development by research firm Carbon8. Its density is under 1200 kg/m3.

Their system uses CO2 during the clean-up of waste, contaminated matter and recycled building materials. By capturing the CO2 during treatment, the carbon footprint of the final product is reduced significantly. Waste material is mixed with water and then carbonated. The producers then combine the carbonated residue with recycled waste material, such as wood shavings, shells and glass.

The result is a brick that captures 14 kg more CO2 per tonne than is used to make it, leading to its carbon negative label. It acts as a carbon battery, and in the future the trick will be not to re-release the carbon when the brick is itself recycled. It can be used as new aggregate; the ACT matter can be used in bound applications, such as concrete. The producers expect to see the Carbon Buster used in projects later this year.