Queen’s University leads research to reduce concrete’s carbon dioxide emissions

Researchers at Queen's University are working with industry partners and the city to reduce the emissions footprint of reinforced concrete.

Reinforced concrete is a common construction material but a lesser-known polluter. The cement-steel mix accounts for almost 10 per cent of global carbon dioxide emissions, far exceeding the roughly two per cent produced by the airline industry.

At the beginning of 2022, researchers at Queen’s University launched a research project in collaboration with the city and industry partners to develop ways of reducing concrete’s emissions footprint.

“Where all the CO2 comes from is the processes of turning them from naturally occurring rock and naturally occurring iron into concrete and steel,” explains Neil Hoult, a professor in the department of civil engineering at Queen’s University.

Not to mention emissions produced by the mining of those materials.

With cities like Kingston building more high-rise apartments and infrastructure, protecting the earth from climate change is also becoming urgent.

Hoult, fellow professor Josh Woods and their graduate students are currently testing how the construction industry could cut those emissions through two main approaches.

The first is shape optimization, or finding a way to design structures to use less concrete; the second is functionally grading the concrete.

“In a concrete structure, there is usually only a couple of places where we see the maximum stresses — in other words, where we need the maximum strength of material — and everywhere else we don’t actually need that material strength,” Hoult said.