Sustainable construction materials company, Lafarge Canada (Lafarge), and power company, TransAlta Corporation (TransAlta), have entered an agreement to advance low-carbon concrete projects in Alberta, replacing cement as a concrete constituent with a waste product, fly ash.
The fly ash is in a landfill west of Edmonton, a waste product of TransAlta’s Canadian coal-fired electricity operations, which ended in 2021.
Landfilled fly ash first must go through a beneficiation process to be used in concrete. The project will utilize Ash-TEK’s ponded ash beneficiation system (PABS) technology, which consistently produced high quality ash during trials and proved to have a low carbon footprint and an economical operating cost. Lafarge will deploy this unique approach to the process, removing moisture from the ash, milling it, and removing excess carbon—ensuring it meets regulatory standards and market expectations.
Geocycle, a provider of sustainable waste management services worldwide, and Lafarge’s subsidiary in Canada, will also join the initiative. The organization brings experience in managing millions of tonnes (tons) of fly ash in the U.S. “Landfilled fly ash sometimes has too much carbon, which affects how much air there is in the concrete. Once we can treat and separate that carbon, then the fly ash is ready to be used (up to 25 percent standard replacement) in place of cement,” says Sophie Wu, head of Geocycle, North America.
Although the role of fly ash in concrete manufacturing is not new, the technology for beneficiation is highly exact and specialized. “We recognize that seizing opportunities to optimize cement is a key part of our CO2 reduction strategy,” says Brad Kohl, president and CEO, Lafarge Canada (West). “Thinking outside the box is a part of how we do business.”
In November 2021, Lafarge Canada was awarded $15 million from the Government of Alberta through Emissions Reduction Alberta (ERA) to advance this project with TransAlta. “Innovation works best when we collaborate,” says Kohl. “The support of ERA is essential to help us drive this progress. Now, we’re not just talking about it—we’re doing it right here in Alberta.”