Sustainable concrete is a relatively novel idea that could transform the construction industry.
Concrete, dubbed "the most destructive material on Earth" by the Guardian, is a building block of an industry, society, and globalized life on this planet. But it's just about the worst human-made substance when it comes to environmental impact.
It's the most common global construction material, and a key component of it, cement, accounts for 8% of worldwide carbon dioxide pollution, according to the University of Victoria. So, cementless concrete would work wonders in lowering carbon pollution.
That's just what Rishi Gupta of the UVic Facility for Innovative Materials and Infrastructure Monitoring is working on. The engineer and professor is leading a team "pushing the boundaries of what can be done with concrete by replacing cement with other sustainable binding materials, providing an alternative to carbon dioxide sequestration," according to UVic News.
Gupta started 10 years ago, using fly ash and bottom ash from coal power plants to improve geopolymer concrete, which binds at room temperature and thus is more sustainable than traditional Portland cement concrete. Usually, these ashes end up in landfills.
The concrete was made with 50% fly ash and 50% bottom ash and cured at ambient temperatures, per UVic News. Alkali activators helped it harden and form such products as pavers, used for pavements and parking lots in the university's partnership with the India-Canada Impacts Centres of Excellence, which "develops, tests, and scales up local solutions for India and Canada," UVic News reported.
"We wanted to take the difficult and less-traveled route of dealing with the bottom ash — in addition to fly ash — as another sustainable option," Gupta said.
He added: "Geopolymer concrete needs heat during the initial curing period to make it stronger. But heat means energy, and producing energy can be a sustainability issue due to associated greenhouse gas emissions.
"... What we are doing is using sustainable technology and demonstrating its application in the real world. The fact that our geopolymer mixes require little to no heating of concrete during production is the greenest part of our research."
The international team is boosted by a pipeline of students from India's Nirma University, and UVic News noted the excitement around the climate action research.
Gupta and his team are also studying the long-term effects of carbon dioxide sequestration. They're examining durability, which includes corrosion resistance, and using "special types of green fibers in CO2-sequestered concrete to make it crack-free and self-healing," UVic News reported.
Such a development would be key to reducing the carbon pollution that results from erecting buildings by extending their lifespans.
These are not the only inventions sweeping the industry, though. A startup is working on a similar product called "green concrete," and "Sugarcrete" could also lessen our reliance on traditional concrete.
The goal is to cut the 4.4 billion tons of carbon dioxide UVic reported is produced annually from cement.
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