PORTLAND Ore. (KPTV) - Chief engineers from the City of Portland’s infrastructure bureaus – Environmental Services, Water, and Transportation – approved recommendations last month to use lower-emission concrete requirements for all city construction projects going forward.

According to a statement Thursday, the recommendation is in line with the city’s commitment to climate action and climate leadership.

“Most of us don’t think much about the concrete beneath our feet. As the most widely used building material in the world, it has a significant environmental impact,” said Stacey Foreman, the city’s Sustainable Procurement Program Manager. “Portland is a leader in establishing these thresholds and in our approach of bringing multiple stakeholders together to develop them.”

The largest ingredient in concrete is cement and cement production alone generates eight percent of global greenhouse gas emissions. According to the city’s engineers, lower-carbon mixes can be designed to perform as well as, or better, than conventional concrete, and are competitive in cost.

The city uses concrete for many projects, including sidewalks and ADA ramps, bicycle and pedestrian paths, fire hydrant pads, retaining walls for parks, and large infrastructure projects such as the Water Bureau’s Bull Run filtration facility and the Bureau of Environmental Services’ wastewater and stormwater infrastructure.

The new standards take effect in January, but projects are already underway that use low-carbon concrete:

According to the statement, Portland developed the new requirements with experts that offered recommendations on reducing the carbon footprint of concrete used in city projects and these requirements will result in a 3 to 35-percent reduction in greenhouse gas emissions over traditional concrete mixes.

One example provided was, for a large project like a new water reservoir, a 19-percent reduction in concrete-embodied carbon represents a savings of approximately 3.5 million kg-CO2e (carbon-dioxide equivalent). This would be the equivalent of removing 754 gasoline-powered cars off the road or the amount of carbon sequestered by 4,142 acres of U.S. forests (approximately three times the size of Forest Park) for one year.

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