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International effort to reduce concrete’s carbon footprint

A team of civil engineering researchers and industry and municipal partners are working to make one of the highest-carbon dioxide producing industries much cleaner.

Student working at Queen's civil engineering lab
Making the concrete industry more sustainable and environmental-friendly is the main goal of the research partnership.

How environmentally friendly is concrete? Less so than you might think. Reinforced concrete infrastructure accounts for almost 10 per cent of global carbon dioxide emissions – far ahead of the two per cent of carbon dioxide produced by the airline industry.

Working to change that are two Queen’s civil engineering experts Neil Hoult and Josh Woods, together with their academic collaborators at the University of Toronto and the University of Cambridge and a number of industry partners who are invested in making their technology and processes more sustainable.

“If we can reduce the carbon produced in concrete manufacturing by even a fraction, it’s going to have a significant positive benefit,” says Neil Hoult, a professor in the Department of Civil Engineering. “Increased urbanization means that the demand for concrete is going up. Our research aims to cut the carbon dioxide emissions generated by concrete production in half – the equivalent of eliminating the airline industry, twice over.”

The research program is supported by industry leaders like Arup, Aecon, KPMB Architects, and Lafarge, along with the City of Kingston and the Cement Association of Canada, with funding sources including Natural Sciences and Engineering Research Council of Canada (NSERC) and Mitacs.

To achieve the goals set by Queen’s and its partners, several approaches will be explored to reduce carbon utilization. The first one is shape optimization, meaning studying how to better design structures to use less concrete – which reduces both material consumption and structure weight.

Neil Hoult and students
Neil Hoult and students work to reduce carbon utilization in concrete structures.

The second is what’s known as functionally graded concrete.

“We put concrete with higher strength where we need the strength, then we use lower strength concrete (which also means lower cement concrete) everywhere else,” Dr. Hoult explains. “We will be working on software packages that allow for these new techniques to be used in the design, optimizing structures for performance and low environmental impact.”

The bulk of the initial research and testing will be completed in the Queen’s civil engineering labs. Moving from the lab to practical applications, however, will take the project into the real world in Kingston, with the support of city and industry partners. The project includes the design of a demonstration structure at the Kingston Fire and Rescue Training Centre.

“The structure will be actively used by Kingston’s Fire Services as a classroom and as a living lab so that Queen’s and St. Lawrence College students can come and learn about low-carbon buildings. We’re aiming for a net-zero building philosophy,” Dr. Hoult highlights.

Speros Kanellos, Director, Facilities Management, and Construction at the City of Kingston, says the city has been working with post-secondary educational partners on ‘learning hubs’ to investigate new approaches and technologies to aggressively decarbonize infrastructure.

“We are working with the low-carbon concrete research team to develop a real-world application for demonstration purposes and ongoing research,” he says. “It’s really exciting to participate as a partner in the kind of initiative that embodies the City’s and university’s leadership on climate action.”