Canadian Contractor

By Jessica Nelson, Local Journalism Initiative Reporter   

Using concrete to store carbon as Canada transitions to net-zero

Canadian Contractor embodied carbon

May 2, 2023 – Net-zero can’t be achieved unless carbon dioxide removal technologies are used, according to a report released last week, and an Alberta company is helping to pave the way to reduced emissions.

On April 13, the Pembina Institute released a report on the need for Canada to use carbon dioxide removal (CDR) along with emission reduction to hit net-zero target by 2050.

“It is critical to do all we can to make early, deep and sustained reductions of direct emissions from industry, transportation, agriculture and other sectors,” the report reads.

Carbon Upcycling, a company from Calgary, is exploring the CDR potential in concrete by using waste material to reduce the amount of cement in concrete and combining it with flue gas CO2 to make the end product more durable.


But what is CDR and why is it needed?

The Pembina Institute report said CDR can be an “indirect solution for hard-to-reduce emissions,” and “can extract some of the legacy carbon that humanity has released into the atmosphere over the last few centuries.”

According to the report CDR is a method to extract CO2 from the atmosphere and store it so “it does not re-enter the atmosphere.” The process must remove more C02 than it emits, and it is an additional measure to “anything that is already happening.”

There are two types of CDR engineered and biological. Biological CDR solutions include afforestation, reforestation, soil sequestration.

Engineered non-biological CDR solutions are newer technologies that, according to the report, could play a larger role in the future, “but need additional attention getting there.”

These newer technologies include direct air capture, ocean alkalinity enhancements, carbon mineralization, geological storage, and carbon use “which takes carbon dioxide and turns it into products” which includes concrete.

Dante Luu, spokesperson for Carbon Upcycling, said in cement there is a raw material called clinker that is made up of limestone.

“When you heat limestone up, super, super hot, then a bunch of CO2 is released from it, and your end result is clinker, that clay gets put into your cement,” he said.

Luu said Carbon Upcycling offsets the cement and carbon- intensive clinker with waste material.

“We’ll take recycled glass, or we’ll take fly ash from coal production or steel slag from steel, and we’ll combine that with CO2. Now the CO2 comes from like your flue gas from natural gas power plant. We’ll combine that CO2 with waste to offset the cement in concrete.

“So, you have less raw material going into your cement,” he said.

The concrete itself is more durable because of the chemical composition of the materials, Luu explained.

“You actually have more resilient concrete at the end of the day. So, when I say resilient, that means it’s able to fend off chloride and sulfate attacks much better. It’s stronger and more durable. We’ve seen like a 40 to 60 per cent increase in strength and durability,” he said.

Luu said it is important to reduce the amount of embodied carbon in concrete because we are surrounded by concrete.

According to the Government of Canada, concrete is the most used building material on the planet. In Canada, cement accounts for 1.5 per cent of CO2 emissions while globally cement accounts for seven per cent of C02 emissions.

“If we can reduce that by say, one per cent, then we’re kind of obligated to,” said Luu. (The concrete industry) is one of the largest emitters in the world, but it’s almost never talked about. So, it’s this massive problem, and that’s kind of what we’re tackling here.”

In February, the government of Alberta announced $58 million for circular economy projects through Emissions Reduction Alberta (ERA). Carbon Upcycling received $4.4 million for a project that will “support the first commercial-scale deployment of two carbon capture and cementitious material production facilities in the Albertan construction sector.”

Carbon Upcycling is partnered with BURNCO and Lafarge for the project.

“This project will support the first commercial-scale deployment of two carbon capture and cementitious material production facilities in the Albertan construction sector,” the ERA website stated.

Luu said Carbon Upcycling is working on reducing the embodied carbon and dealing with waste.

“You have waste from steel, you have waste from coal, waste glass, and all this stuff just ends up in a landfill. What we’re doing is we’re upcycling it or in other words transforming this waste into a valuable material for another industry, building that circularity,” said Luu.


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