Push for low-carbon concrete taking longer to solidify than anticipated

The city of Austin is following up on its promise to transition to low-carbon concrete, though it says the plan will take several years to settle into place.

Staff from the Office of the City Engineer joined the Joint Sustainability Committee last week for the first update since City Council’s resolution to mandate standards for lower emissions for cement mixes used on city projects last April. While staffers insist they have sprung to action gathering construction emissions data and reaching out to local concrete vendors, they say a lag in industry participation and public safety concerns will likely drag out implementation to sometime in 2026.

With its manufacturing accounting for around 8 percent of greenhouse gas emissions worldwide, the concrete industry has become a focal point for decarbonization strategies for administrations across the globe racing to mitigate the mounting climate crisis. At a local level, staff says concrete used in city capital projects accounted for nearly 78,700 metric tons of Austin’s carbon emissions in Fiscal Year 2023.

Concrete’s emissions footprint is driven largely by cement production, a heat-intensive process that uses large amounts of energy while releasing its own share of carbon dioxide into the atmosphere. While trailblazers like CarbonCure Technologies have patented new production methods that deposit the harmful byproduct as a mineral product in its concrete mix, industry peers have been slow to get on board. Out of the city’s 12 concrete suppliers, only one, Lauren Concrete, has implemented the practice.

Staffers say their current focus is developing new protocols for suppliers, including Environmental Product Declaration standards mandating certain greenhouse gas emissions thresholds for concrete mixes. That number could range anywhere from 345 to 380 kilograms of carbon dioxide per cubic meter of product, though that could change before their targeted rollout this October. 

After establishing some ground rules, city engineers say it will take another year or two of testing and tinkering to shift the protocols into practice. 

“We will be dealing with cement for a while,” said managing engineer Angela Johnson. “Moving to that Environmental Product Declaration process, unfortunately there’s just a timeline which we cannot expedite. … We’re dancing with industry – we move when they’re ready to move because of legal complications. We’re trying to be careful.”

“We’re aware that anything that affects city purchasing can be challenged a lot, and we don’t want to be in a position of setting something that seems punitive,” consulting engineer Ed Poppitt said. “It’s counter to making fast progress, but it’s what industry has been telling us, to be cautious about how quickly we’re pushing them.”

To no one’s surprise, commissioners are hoping for a more aggressive timeline, particularly as the deadline to meet 2030 emissions targets laid out in the city’s Climate Equity Plan looms steadily around the corner.

“My feedback would be that your plan sounds a little bit too accommodating to industry, and I think you could accelerate those timelines a little bit, especially hearing that you already have some producers with Environmental Product Declarations and at least one actively using a greenhouse gas reduction strategy,” said Commission Chair Kaiba White. “I mean, we’re literally on fire here, right? We can barely keep our grid running because of climate change, and people are dying of heat exposure. It’s serious.”

As they continue plotting out logistics, staffers say they are looking to organizations like the American Concrete Institute for leadership on the latest carbon-neutral practices, as well as to cities like Portland, which launched its own carbon-neutral concrete initiative ahead of the curve back in 2016.

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