Oregon State University’s Jason Weiss said that concrete emits relatively low amounts of carbon compared to other building materials. But because it's so commonly used, it's responsible for about 5% of the world’s carbon dioxide emissions.
However, Weiss, head of OSU’s School of Civil and Construction Engineering, told U.S. Representative Peter DeFazio during presentations Friday that the university is working to reduce those carbon emissions.
DeFazio, chair of the House Transportation & Infrastructure Committee, spent about two hours at the university, visiting various labs, including the Concrete Performance Lab, which studies alternate compositions for concrete; the Hinsdale Wave Research Lab and the Driving and Bicycling Simulator Lab.
DeFazio’s visit was prompted by OSU's recent $1.3 million Advanced Research Projects Agency–Energy grant to develop a computer model to help cement-makers understand how mixing in other materials will affect the properties of the concrete it produces.
“Cement is the flour and concrete is the cake,” he said.
Weiss, who added that that OSU hasn’t yet finalized the grant agreement, said mixing byproducts of other industries, like slag or fly ash, into concrete can reduce the amount of carbon emissions from its production. A lot of carbon is released when cement is heated in kilns as it is produced.
However, he said up to 50% of the mix can be replaced with other materials, which would reduce the amount of cement that needed to be produced, meaning less emitted carbon. This can also lower the cost of the cement, since the added materials are low-cost byproducts of other industries. The resulting concrete can have similar or even better properties than traditional concrete.
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Weiss said the university is already studying a more radical change to concrete, essentially a new mix for cement called Solidia cement. According to Weiss, it can be produced at a lower temperature so there are less carbon emissions in the kilning process, but it also captures carbon from the atmosphere.
“It’s a very different process,” he said. “It essentially can be a CO2 negative concrete, which is really exciting.”
Weiss told DeFazio that the university has been working with state departments of transportation across the country to change road construction specifications and allow the new variety, which outperforms traditional concrete in durability tests.
DeFazio asked if the new variety would require a new type of kiln to manufacture, because many cement makers wouldn’t want to take on the cost of replacing existing kilns.
Weiss said the Solidia cement can be produced in a traditional kiln. If the new mix were widely adapted, he added, it would be the equivalent of taking a million cars off the road.
DeFazio learned a lot from the presentations and said he may ask Weiss and others to testify before the Transportation & Infrastructure Committee in the future.
“We have a fantastic asset here at OSU to help me with transportation,” he said.