Designing Cleaner, Greener Concrete That Absorbs Carbon Dioxide

From the mud, straw, and gypsum mixtures of ancient Egypt’s monumental pyramids to the sophisticated underwater material employed by Roman engineers in iconic structures like the Pantheon, concrete has long symbolized civilization’s resilience and ingenuity.

Yet today, concrete finds itself in a paradoxical bind: The very material that allowed societies to flourish is also responsible for up to 9% of global greenhouse gas emissions. Climate change, itself deeply rooted in fossil fuel use, presents humanity with an existential challenge if people seek to sustainably build the structures that support modern life—namely, new homes, highways, bridges, and more.

Now, designers, materials scientists, and engineers from Penn have teamed up to create a biomineral-infused concrete by blending 3D printing with the fossil architecture of microscopic algae. This concrete is remarkably lightweight—yet structurally sound—and captures up to 142% more CO₂ than conventional mixes while using less cement and still meeting standard compressive-strength targets.

The key ingredient is diatomaceous earth (DE), a popular filler material made from fossilized microorganisms. The researchers found that the fine, porous, and sponge-like texture of DE not only improves the stability of concrete as it’s pushed through a 3D printer nozzle but also provides abundant sites for trapping carbon dioxide. These findings, which are reported in Advanced Functional Materials, pave the way for building materials that both hold up bridges and skyscrapers and help restore marine ecosystems and capture carbon from the air.

She notes that the team not only achieved “an additional 30% higher CO₂ conversion” when the geometry of the material was further optimized, but did so while maintaining a compressive strength comparable to ordinary concrete. “It was one of those rare moments where everything just worked better and looked nicer,” she says.

“But it wasn’t just about aesthetics or reducing mass,” adds co-senior author Masoud Akbarzadeh, associate professor of architecture at Weitzman. “It was about unlocking a new structural logic. We could reduce material by almost 60%, and still carry the load, showing it’s possible to do so much more with so much less.”

Read the full story via Penn Today.