Concrete accounts for about 8% of the world’s greenhouse gas emissions, notes CNN. But a research team at the University of Pennsylvania just used a robotic 3D printer to construct a bridge with “complex, lattice-like patterns” that are just as strong and durable — but with materials that absorb more carbon dioxide.
Check out the photos of the “Diamanti” projects “post-tensioned concrete canopy”. And CNN’s report includes an animated photo showing the 3D printer in action:
While most regular concrete absorbs carbon dioxide (up to 30% of its production emissions over its entire life cycle, according to some research), Diamanti’s enhanced concrete mixture absorbs 142% more carbon dioxide than conventional concrete mixes. Its first design, a pedestrian bridge, uses 60% less material while retaining mechanical strength, says Masoud Akbarzadeh, an associate professor of architecture at the University of Pennsylvania and director of the lab that spearheaded the project.
“Through millions of years of evolution, nature has learned that you don’t need material everywhere,” says Akbarzadeh. “If you take a cross section of a bone, you realize that bone is quite porous, but there are certain patterns within which the load (or weight) is transferred.” By mimicking the structures in certain porous bones — known as triply periodic minimal surface (TPMS) structures — âDiamanti also increased the surface area of the bridge, increasing the concrete mixture’s carbon absorption potential by another 30%… According to Akbarzadeh, 3D printing reduces construction time, material, and energy use by 25%, and its structural system reduces the need for steel by 80%, minimizing use of another emissions-heavy material. He added that using the technique with Diamanti’s concrete significantly cuts greenhouse gas emissions compared to regular construction techniques, and reduces construction costs by 25% to 30%.
“Even without the material innovation, the higher surface itself allows higher CO2 absorption,” one engineering lecturer tells CNN. The project was a collaboration with chemical company Sika, funded with grants from the U.S. Energy Department, and is now preparing its first full-size prototype in France.
The team has published their findings in the journal Advanced Functional Materials earlier this year.