This project demonstrated how agricultural waste could be transformed into sustainable concrete products, helping Northern Ireland move closer to its net zero goals. Led by academics at Queen’s University Belfast, in collaboration with AFBI, United Renewables, Mannok, Breedon, Irish Cement, and supported by the Mineral Products Association NI, the team focused on converting digestate—a byproduct from anaerobic digestion—into biochar through pyrolysis.
The biochar, rich in carbon and minerals like calcium and silica, was used to partially replace cement in concrete mixes. This approach not only reduced the environmental impact of digestate disposal but also enhanced the performance of concrete. Factory trials showed that roof tiles made with biochar achieved up to a 20% reduction in carbon emissions, while maintaining strength and durability.
The project highlighted the potential for biochar to act as more than just a filler—it contributed to early strength development, improved curing, and even enabled self-repairing properties in concrete. By decentralising waste management and linking agriculture with construction, the initiative created a circular economy model that valorised waste and reduced emissions.
With Northern Ireland’s construction sector responsible for up to 900,000 tonnes of CO₂ annually, this innovation offers an instantly scalable solution. The research team optimised biochar proportions to meet industry standards and continued to explore broader applications, including structural and non-structural concrete products.
This work laid the foundation for future collaboration between sectors, showcasing how local resources and cross-industry partnerships could drive sustainable innovation in building materials.