Researchers at the University of Washington and Microsoft have developed a new type of sustainable concrete using powdered seaweed.
By blending dried green algae with cement, the team created a substance with 21% lower global heating potential while maintaining structural strength, according to the study published in the journal Matter.
The long-term goal of the research is to serve as a foundation for the design and implementation of sustainable biomaterials. It also demonstrates how we can lower the carbon footprint of cement and integrate life-cycle assessment testing with experimental materials and machine learning technology to advance sustainability.
This development and framework for the future are crucial as concrete is one of the world's most-polluting materials. According to the World Economic Forum, global cement production accounts for 8% of total global carbon pollution, contributing to rising global temperatures and increasing health risks.
Concrete is essential for constructing bridges, roads, dams, and buildings, but its production releases over 4 billion tons of carbon dioxide annually, per Yale Environment 360.
Calcining cement's primary materials at 1,500 degrees Celsius in a kiln emits large amounts of carbon dioxide and produces chemical reactions. Citing data from the National Ready Mixed Concrete Association, Princeton University noted that each pound of concrete releases 0.93 pounds of carbon dioxide.
Seaweed, however, acts as a carbon sink while it grows. It doesn't require complex, costly treatments, and it can be used in its dried, powdered form, making it an accessible option for scaling low-carbon concrete globally.
"What makes this work exciting is that we show how an abundant, photosynthetic material like green seaweed can be incorporated into cement to cut emissions, without the need for costly processing or sacrificing performance," said Eleftheria Roumeli, a senior author of the study and a UW assistant professor of materials science and engineering.
Normally, finding the right mix of new ingredients would take years of trial and error, but the team used a custom machine learning model to predict successful blends, feeding results back into the system to perfect the seaweed-based formula in just 28 days, a process the team predicted to otherwise have taken five years.
This new cement can reduce production costs, improve concrete performance, and utilize alternative materials that require less time, labor, and resources. This results in cheaper products, homes, and repairs, as well as savings for consumers while reducing long-term health risks from carbon pollution.
The team now aims to explore even more seaweed mixtures that influence cement production and performance. Using machine learning, the researchers also envision a system where producers can quickly develop their own sustainable, often stronger, cement mix with localized materials like different algae species, food waste such as coffee grounds, seashells, and more.
"By combining natural materials like algae with modern data tools, we can localize production, reduce emissions, and move faster toward greener infrastructure," Roumeli said. "It's an exciting step toward a new generation of sustainable building materials."