Boral Limited has successfully produced concrete made with recycled concrete aggregates that have been recarbonated using carbon capture technology from its integrated cement manufacturing plant, marking a first-of-its-kind trial in Australia.
The demonstration saw recycled concrete aggregates from Boral’s Widemere recycling facility used to capture and permanently store CO2 from flue gas diverted from Berrima Cement Works’ operations into its new recarbonation-based carbon capture and storage (CCS) pilot plant.
These recarbonated recycled aggregates were then used to partially replace natural coarse aggregates in a low carbon concrete mix produced at Boral’s Maldon cement manufacturing facility.
The trial, jointly funded by the federal government’s Carbon Capture, Use and Storage (CCUS) Development Fund and Boral, used the company’s low-carbon Envisia® concrete mix with 50 per cent of natural coarse aggregates replaced by recarbonated recycled aggregates.
Dr Ali Nezhad, Head of Sustainability and Innovation at Boral, said: “We’re proud to lead the development of utilisation pathways for recarbonated concrete aggregates.
“Its successful use not only enhances the viability of recarbonation-based carbon capture technology but also offers the potential for a further reduction in the embodied carbon of concrete by replacing natural aggregates.
“The success of our carbon capture pilot plant at Berrima further validates the potential of recarbonation and underscores the importance of its broader recognition.”
One of the unique characteristics of concrete is that it naturally absorbs carbon dioxide over its service life and beyond.
This process, known as cement recarbonation, is typically slow but accelerates when concrete is crushed into recycled aggregates at end of life, as more surface area is exposed.
The CCS pilot plant at Berrima mimics and accelerates this natural process under controlled conditions, enabling faster and more efficient uptake of CO2.
The CCS process represents a low-cost, practical approach to capturing and permanently storing carbon, with the potential to address process emissions that account for approximately 65 per cent of cement production’s carbon footprint.
Vik Bansal, CEO and Managing Director at Boral, said: “At Boral, we are committed to a lower-carbon future, and we believe recarbonation will play an important role in decarbonising the cement and concrete industry.
“The successful accelerated recarbonation of recycled concrete aggregates at our CCS pilot plant at Berrima and utilisation of these aggregates in concrete further reinforce the potential of this technology.
“Alongside our significant investments in alternative fuels and alternative materials to decarbonise our cement manufacturing operations in the short term, we remain committed to exploring technologies like carbon capture and storage as part of our long-term journey towards our net zero ambition by 2050.”
The United Nation’s Intergovernmental Panel on Climate Change (IPCC) has highlighted the role of cement recarbonation in CO2 uptake.
Global studies estimate that recarbonation of concrete can absorb between 20 and 55 per cent of process emissions from cement manufacturing.
