Seaweed-Powdered Cement Reduces Concrete's Carbon Footprint by 21% Without Losing Strength

Seaweed powder is being used to reduce the carbon footprint of concrete without compromising its strength, marking a significant advancement in sustainable construction materials. Researchers from the University of Washington and Microsoft collaborated to develop this innovative solution, which involves mixing dried, powdered seaweed with traditional cement. Cement, a key ingredient in concrete, is one of the most widely used materials globally after water. However, its production is responsible for up to 10% of global carbon dioxide emissions. The primary sources of these emissions are the fossil fuels burned to heat raw materials and the calcination process, a chemical reaction that occurs during manufacturing. In contrast, seaweed acts as a carbon sink, actively absorbing and storing carbon dioxide from the atmosphere as it grows. This characteristic makes it an ideal candidate for reducing concrete's environmental impact. By incorporating seaweed into the cement mixture, researchers have found a way to decrease emissions while maintaining the material's structural integrity. The team’s groundbreaking work, published in the journal Matter, shows that adding 5% seaweed by weight to cement reduces its global warming potential by 21%. Senior author Eleftheria Roumeli, an assistant professor of materials science and engineering at the University of Washington, noted the potential of this approach. "Cement is the foundation of modern infrastructure, but it comes with a significant climate cost," she said. "Our research is exciting because it demonstrates how an abundant, photosynthetic material like green seaweed can be integrated into cement to cut emissions, without requiring expensive processing or sacrificing performance." Traditionally, testing different cement mixtures for optimal performance and properties can take years due to the lengthy curing process, which requires about a month for each sample. To expedite their work, the researchers utilized a custom machine learning model. They trained this model on an initial set of 24 cement formulations, allowing it to predict the best mixtures to test in the laboratory. By continuously feeding the results of these tests back into the model, the team could quickly refine their approach and identify the ideal seaweed-enhanced cement mixture within just 28 days. "Machine learning played a crucial role in dramatically shortening the experimental process, especially given the introduction of a novel material like seaweed into cement," Roumeli explained. Looking ahead, the research team aims to explore how various seaweed compositions and structures affect cement performance. Their ultimate goal is to generalize this method to other types of algae and even food waste, enabling localized and sustainable cement production globally. Machine learning will continue to be a key tool in optimizing these new mixtures. "By merging natural materials like algae with advanced data tools, we can make production more local, reduce emissions, and accelerate the transition to greener infrastructure," Roumeli stated. "This is a promising step toward a new era of sustainable building materials."