Highlights

• Boral uses recycled concrete aggregates recarbonated with CO₂ from cement production in its first Australian trial.
• Envisia® low-carbon concrete replaced 50% of natural aggregates with recarbonated recycled materials.
• Carbon capture and recarbonation could absorb up to 55% of cement-related CO₂ emissions.

Boral Limited, an Australian construction materials company, has developed concrete using recycled concrete aggregates that absorbed carbon dioxide (CO₂) from a cement plant.

This trial is the first of its kind in Australia, where the recycled aggregates came from Boral’s Widemere recycling facility and were exposed to carbon capture technology at Berrima Cement Works.

This process permanently stored CO₂ from the plant’s flue gas in the aggregates, which were later used to partially replace natural coarse aggregates in low-carbon concrete.

Read More: GCCA Launches Low Carbon Rating System for Sustainable Cement

Concrete naturally absorbs CO₂ over its lifetime through a process known as recarbonation. When buildings or structures made with concrete are demolished, the concrete is crushed into recycled aggregates, which have more surface area and absorb CO₂ at a much faster rate.

Boral’s Berrima CCS pilot plant catalyses this natural process by controlling conditions to increase CO₂ uptake. This process allows the concrete to hold more carbon while also utilising materials that would have otherwise gone to waste.

The trial was successfully carried out at Boral’s Maldon cement manufacturing facility, using Envisia® low-carbon concrete. In the test, 50% of natural coarse aggregates were replaced with recarbonated recycled aggregates.

This project received funding from the Federal Government’s Carbon Capture, Use and Storage (CCUS) Development Fund and Boral.

The process is a practical and low-cost path to capture CO₂ emissions from cement production, which account for around 65% of process-related carbon emissions in cement manufacturing.

Also Read: Recycled Cement Cuts Emissions Without Strength Loss, Says Study

Experts say that the recarbonation of concrete could absorb between 20% and 55% of CO₂ emissions produced during cement production, which makes it a promising method to reduce the environmental impact of construction materials.

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 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.”

Ends/

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Source: Boral