According to CNN, concrete is responsible for about 8% of global greenhouse gas emissions. But a University of Pennsylvania research team just used a robotic 3D printer to construct a bridge with “complex, grid-like patterns” that are just as strong and durable – but made from materials that absorb more carbon dioxide.
Take a look at the photos of the “Diamanti” projects “Prestressed concrete canopy”. And the CNN 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 improved concrete mix absorbs 142% more carbon dioxide than traditional concrete mixes. His first design, a pedestrian bridge, uses 60% less material while maintaining mechanical strength, says Masoud Akbarzadeh, an associate professor of architecture at the University of Pennsylvania and head of the lab that led the project.
“Through millions of years of evolution, nature has learned that you don’t need materials everywhere,” says Akbarzadeh. “If you take a cross-section of bone, you find that the 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 TPMS (Triple Periodic Minimal Surface) structures – âDiamanti also increased the surface area of the bridge and increased the carbon absorption potential of the concrete mix by an additional 30%…According to Akbarzadeh, 3D printing reduces construction time, material and energy consumption by 25%, and its structural system reduces the need for steel by 80%, minimizing the use of other emissions-intensive materials. He added that using the technique with Diamantis Concrete significantly reduces greenhouse gas emissions compared to traditional construction techniques and reduces construction costs by 25 to 30%.
“Even without the material innovation, the higher surface area itself allows for higher CO2 absorption,” an engineering lecturer tells CNN. The project was a collaboration with chemical company Sika, funded by grants from the US Department of Energy, and is currently preparing its first full-scale prototype in France.
The team published their results in the journal Advanced functional materials Earlier this year.