Reimagining Precast Concrete for Carbon Storage
Funded through the Grand Challenge: Innovative Carbon Uses Round 1 in 2014, the McGill University project explored the possibility of using the existing precast concrete production for carbon capture, utilization and storage (CCUS) in Alberta. The target of carbon dioxide utilization is 1 million tonnes per year. Researchers examined both cement and aggregate components for their ability to store carbon. Artificial aggregates were produced on-site using calcium-rich industrial waste and activated with CO2, replacing natural sand and stone in concrete mixes. This approach not only stores carbon but also reduces landfill waste, conserves natural resources and helps sequester heavy metals.
The carbonated aggregates were transported to precast plants, where they were combined with cement and cured using CO2 instead of steam. The resulting concrete showed comparable strength to conventional products, with improved durability against freeze-thaw cycles, chloride penetration and efflorescence. These benefits are attributed to the formation of carbonate bonds and refined pore structures. To support full-scale deployment, the project also developed a low-cost, energy-efficient CO2 capture system using self-concentrating absorption and residual heat.
Integrating Carbon Capture into Concrete Making
Building on these findings, the project also demonstrated the potential of artificial aggregates made from industrial waste—such as steel slag, lime sludge and air pollution control (APC) residues—to significantly boost carbon uptake in concrete. These materials, when carbonated, not only stored large amounts of CO2 but also performed comparably to conventional aggregates in strength and durability tests. Full-scale pilot tests showed that each standard concrete block could sequester nearly 3 kg of CO2, with the majority stored in the aggregates. The team also developed a low-cost carbon capture system using 3H self-concentrating absorption technology, capable of producing high-purity CO2 at $10–20 per tonne. This integrated approach—combining waste valorization, carbon capture and concrete production—could help position Alberta’s precast industry to play a leading role in large-scale carbon utilization.
What’s next?
A key milestone was the planned pilot deployment with Lehigh Hanson’s Edmonton facility, where McGill aimed to integrate carbon capture directly into cement and pipe production. While the McGill research group did not pursue further opportunities in Alberta, they went on to form a start-up, CarbiCrete, in 2016. CarbiCrete focuses on replacing cement as the binder in concrete, as well as injecting CO2 for sequestration while enhancing the concrete product’s strength. In early 2021, CarbiCrete launched an industrial-scale pilot project in partnership with Patio Drummond, a Quebec maker of paving 26 stones and other concrete products. Production at their Drummondville plant began on January 29, 2021.