Concrete goes green: UW and Microsoft use seaweed to create novel carbon-trapping cement

Geek Wire

08-07-2025

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Meng-Yen Lin, a member of Eleftheria Roumeli's lab at the University of Washington, mixes up seaweed-containing batter for making cement. (UW Photo)
Researchers have developed a novel solution for trapping carbon in concrete by blending a sustainable, easy-to-grow green seaweed into the industrial batter that makes cement, all without reducing its strength.
Scientists from the University of Washington and Microsoft Research used machine learning to expedite their experimentation, coming up with a solution that lowered the cement's global warming impacts by 21%
A study on their work is publishing online today in Matter, a science journal focused on materials science.
The research was led by Eleftheria Roumeli, a UW assistant professor in materials science and engineering, and Kristen Severson, a senior researcher with Microsoft Research. Roumeli previously developed an algae-based plastic that biodegrades in nature as quick as a banana peel.
The scientists wanted to tackle concrete given that it's responsible for between 8-11% of global carbon emissions. Cement, the key component of concrete, contributes to nearly all of that climate burden.
There are efforts worldwide to curb concrete's carbon footprint by using clean energy in generating the heat needed to product cement and by swapping in different ingredients to bind the cement such as industrial wastes like fly ash and furnace slag.
Scientists with the University of Washington and Microsoft Research used dehydrated seaweed to make a high-performing, lower-carbon cement. (UW Photo)
Roumeli and Severson turned to the seaweed given that it pulls carbon from the air and locks it away during photosynthesis. Others have tested the use of smaller algae, but the researchers were the first to choose a macroalgae called Ulva as their material because it has a more robust cellular structure they suspected could help reinforce the cement.
The scientists dehydrated the seaweed before incorporating it and were able to successfully use much higher amounts in the cement than previous demonstrations.
One of the difficulties in developing lower-carbon cement is the time required to make sure it's strong enough to be used in the construction of buildings, bridges and other infrastructure. Concrete gains strength over time, leading researchers to typically test the material after 28 days.
To speed up that process, the scientists developed a machine learning model that could predict how much stronger a sample would get over four weeks, allowing them to abandon underperforming strategies earlier in the process. The approach shaved 112 days off of experiment time. The model is adaptable and can be applied to other solutions for making greener cement.
'[T]his work establishes a framework with the potential to accelerate the design of sustainable cement with feasible experimental resources while satisfying critical performance requirements,' the authors wrote.
Other authors of the paper were Meng-Yen Lin and Paul Grandgeorge, who did the research as a graduate student and a post-doc, respectively, in Roumeli's lab. The publication is titled 'Closed-loop optimization using machine learning for the accelerated design of sustainable cements incorporating algal biomatter.'