Mayors Urging All Cities to Consider Using Carbon Dioxide Mineralized Concrete for Future City Building and Infrastructure Projects

The built environment is responsible for over 40% of the world’s CO2 emissions and global building stock is expected to double by 2060. Concrete is the most widely used construction material in the world due to its affordable and durable nature. And its key ingredient, cement, contributes to up to 7% of the world’s CO2 emissions. Companies like CarbonCure are helping lead that charge with CO2 mineralized concrete.

“The cliche really stands that cities are the laboratory of innovation,” CarbonCure CEO Robert Niven told Smart Cities Dive. “And cities are really committed to taking a leap on solving this climate change issue.” 

The resolution was modeled after an initial resolution implemented by the Honolulu City Council. Honolulu has taken the lead to help the city, county and state achieve its goal to be carbon neutral by 2045.

About 1 million cubic yards of concrete were made in Hawaii last year, representing 756 million pounds of CO2 emitted from the concrete’s life cycle, Honolulu Mayor Kirk Caldwell told Smart Cities Dive in an email.

CarbonCure on average reduces about 25 pounds of CO2 per cubic yard of concrete, representing the potential to save about 27 million pounds of embodied carbon from the concrete produced in Hawaii.

“Concrete made from recycled CO2 is a win-win from a mitigation and adaptation standpoint: it embodies carbon thereby keeping it out of [the] atmosphere so it can’t contribute to further global heating, and it strengthens our roads and infrastructure against accelerating impacts,” Caldwell said.

“In addition, this material needs less energy and materials to make, so it has the potential to further support the sustainability and resilience of our city budgets.”

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CarbonCure fits into existing production and supply chain processes, according to Niven, and provides concrete producers with the technology to consume carbon dioxide in the production of concrete, reducing costs and carbon footprint.

The carbon-injected concrete can also provide concrete companies with a competitive advantage as cities prioritize reducing their carbon footprint, Dawn Lippert, the CEO of nonprofit tech accelerator Elemental Excelerator, told Smart Cities Dive in an email.

“Switching to carbon-injected concrete — in every new street and sidewalk and building and parking lot — is one of the most immediate ways a city can slash emissions. Because not only are you using less CO2-emitting cement, you’re doing so by putting CO2 captured from other industrial process to productive use,” she said. 

Niven said he expects to see CO2 mineralized concrete used as a best practice in the near future. “Our overall goal is to reduce over 500 million tons of CO2 emissions a year and that’s going to require very broad adoption of CarbonCure globally,” he said.

In order to scale the technology at the pace required to get ahead of climate change, the right policy environment needs to be in place, Niven said. He expects the U.S. mayors’ statement will establish a policy shift in the U.S. and internationally.

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Produced by Island Ready-Mix Concrete using waste carbon dioxide from Hawaii Gas, the carbon dioxide is mixed into the concrete using CarbonCure technology. The resulting product traps carbon dioxide in mineral form within the concrete and improves the comprehensive strength of the material

Credit: National Park Service

Jason Plautz@Jason_Plautz, July 8, 2019

  • The Hawaii Department of Transportation (DOT) plans to use carbon-injected concrete in all construction as part of its climate change solution. The material is now approved for all flat work, like roads and sidewalks, and is being tested for use in vertical projects. 
  • In an interview with Smart Cities Dive, Edwin Sniffen, deputy director of highways for the Hawaii DOT, said the carbon-injected material has turned out to be stronger and more workable, with no increase in cost over traditional concrete. 
  • Green concrete can reduce embodied carbon by 25 pounds per cubic yard, according to the state. A demonstration project that poured 150 cubic yards saved an estimated 1,500 pounds of carbon dioxide (CO2), the equivalent of 1,600 miles of highway driving. 

Transportation is the largest source of greenhouse gas emissions, but reducing its impact largely requires turning over fleets of gas-powered vehicles to hybrid or electric cars. Focusing on infrastructure was an area where Hawaii felt it could make an impact, Sniffen said, since the government can control what cement is used for publicly-funded projects.

According to the think tank Chatham House, cement production produces about 8% of the world’s greenhouse gas emissions, and even though production has grown more efficient, higher demand means the industry has not lowered its overall emissions. 

“Definitely we’d like everyone to convert to clean vehicles,” Sniffen said. “But while we work towards electrification, this is a step we can take now.”

The state is using technology from Canadian startup Carbon Cure, which sources CO2 from industrial facilities and converts it into a mineral that is injected into concrete, replacing some of the cement mix. A field test in May showed that the technology was workable for flat surfaces — in fact, Sniffen said contractors found it easier to work with than traditional concrete. Now it is being tested to see if it will work for more intense projects, including a rockfall protection wall and bridges. 

The goal is not just to have it be used by the DOT, but by other state agencies for areas like apartment buildings. The Honolulu city council in April passed a resolution calling on the city to consider CO2-injected concrete wherever applicable. (The DOT tests had been in the works before the resolution was passed.) 

Other states are also exploring mandates for greener concrete; Reutersreports that both New York and New Jersey are exploring legislation, and Austin, TX has been weighing how green concrete could be used. Costremains a concern for some governments and private companies, but CO2-injected cement could provide a path forward for states like New York that have set goals to offset greenhouse gas emissions by capturing some carbon dioxide. 

HAWAII DEPARTMENT OF TRANSPORTATION HDOT Tests Sustainable Concrete Mix Designed to Reduce Carbon Footprint of Road Construction


HONOLULU – The Hawaii Department of Transportation (HDOT) is testing a concrete mix injected with waste carbon dioxide as a sustainable transportation initiative. The test involves a pour of 150 cubic yards of carbon-injected concrete next to an equivalent pour of standard concrete mix on an access road for the Kapolei Interchange Phase 2.

This test will allow HDOT to do a side-by-side comparison of the two mixes to determine specifications for the use of carbon-injected concrete for road projects in the future.

“I am pleased to see HDOT moving ahead with CarbonCure, local concrete companies, and Hawaii Gas to reduce the levels of carbon dioxide emitted during the construction process,” said Governor David Ige. “As the daily baseline measurement for carbon dioxide in our atmosphere reaches the highest level in modern history, it is especially important for all of us to do all we can towards ensuring a sustainable Hawaii for future generations.”

The carbon-injected concrete used in the testing is produced by Island Ready-Mix Concrete using waste carbon dioxide from Hawaii Gas. The carbon dioxide is mixed into the concrete using CarbonCure technology. The resulting product traps carbon dioxide in mineral form within the concrete and improves the comprehensive strength of the material. This project is supported by Elemental Excelerator—a Hawaii-based startup accelerator that has supported more than 50 projects alongside startups, local businesses, and government agencies. “We are proud that Hawaii is looking at sustainable building practices to mitigate the effects of climate change,” said Aki Marceau, managing director for the Elemental Excelerator.

Depending on the final specifications, the use of carbon-injected concrete could reduce embodied carbon by 25 lbs. per cubic yard. A mile of concrete pavement uses roughly 21,000 cubic yards of concrete. The amount of concrete poured in the HDOT demonstration project will save 1,500 lbs. of carbon dioxide, offsetting the carbon dioxide emissions from 1,600 miles of highway driving.

Concrete is the most abundant manmade material on earth and is responsible for seven-percent of global manmade greenhouse emissions, making it the world’s second largest industrial source of carbon dioxide, according to the International Energy Agency.

Photos and videos of the production pour this morning and interviews with Christie Gamble of CarbonCure and Aki Marceau from the Elemental Excelerator can be found at this link.

About CarbonCure

CarbonCure Technologies Inc. is the global leader in carbon dioxide (CO2) utilization technologies for the world’s most abundant man-made material: concrete. The retrofit CarbonCure Technology chemically mineralizes waste CO2 during the concrete manufacturing process to make greener and stronger concrete. CarbonCure has partnered with more than 130 concrete producers across North America and Asia to create new production cost savings, gain competitive sales advantages, and reduce the carbon footprint of the built environment.

About Elemental Excelerator

Elemental Excelerator helps startups change the world, one community at a time. Each year, it finds 15-20 companies that best fit its mission and fund each company up to $1 million to improve systems that impact people’s lives: energy, transportation, water, agriculture, and beyond. To date, Elemental Excelerator has awarded over $30 million to 82 companies.

REUTERS U.S. lawmakers take a concrete step to battle emissions