Businesses and governments looking to reduce their carbon footprint are turning to an unlikely source: concrete. The ubiquitous product—used in roads, bridges, buildings and sidewalks—is responsible for about 8 percent of greenhouse gas emissions worldwide.
“Concrete is the second most consumed substance on Earth after water,” said Jay Mustard, materials management specialist for DEQ’s Eastern Region. “We pave a lot of this planet.”
Now concrete producers, with the help of DEQ, are measuring and reporting the environmental impacts of different mixtures to meet market demands for greener concrete.
Traditional concrete mixtures use cement as the glue that holds the rocks and sand together. Cement is derived from limestone, which is naturally high in carbon dioxide. When limestone is heated to very high temperatures during the cement production process, it releases its naturally occurring carbon dioxide. About half of the carbon emissions produced during this process are from the limestone itself, with the other half coming from the fossil fuels burned to generate heat for the kiln.
Lower-carbon formulas use a cement alternative like slag, a byproduct of steel manufacturing that would otherwise be headed for a landfill. There are several other substitutes that also have significantly lower carbon emissions than cement. These alternatives can reduce carbon emissions from concrete up to 50 percent and are usually available at a similar price.
Jordan Palmeri, senior policy analyst in DEQ’s Headquarters, has worked with local Oregon concrete producers, including CalPortland, Hooker Creek and Knife River, to develop Environmental Product Declarations for several concrete mixtures. These third-party certifications provide consumers information about the environmental impacts of making the product—similar to nutritional labels on food products.
Having an Environmental Product Declaration scores points in the LEED green building rating system and is a selling point for local governments and businesses that have carbon reduction goals. DEQ runs a voluntary program with the Oregon Concrete and Aggregate Producers Association that provides concrete producers with resources and financial incentives to develop these declarations.
“This is one of these options where the technology, materials, opportunity is there — it just needs to be used more,” said Palmeri.
Because of DEQ’s work, the city of Portland recently passed an ordinance requiring concrete Environmental Product Declarations to be submitted on all city construction projects, and the city of Bend incorporated recommendations about concrete into its forthcoming Climate Action Plan, which the Bend City Council is scheduled to vote on early this winter.
Mustard is also advising Facebook’s sustainability director on the possibility of using low-carbon concrete for the massive data centers Facebook is building in Prineville and other locations around the world.
“Getting cities and businesses to switch to low-carbon mixtures can have a huge impact,” said Mustard. “And I think they’re going to do it.”
Learn more about the tools DEQ and partners developed to support low-carbon concrete at the Oregon Concrete Environmental Product Declaration Program webpage.
— Laura Gleim, public affairs specialist