Researchers Build Complex 3D-Printed, Carbon-Absorbing Bridge Inspired by Bones (cnn.com) 13
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.
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.
Please don't mislead by math . . . (Score:3)
Re: (Score:2)
no question that it is an improvement. but that's not all, i'm totally baffled by cnn's "animated photo"! this is surreal! video is dead!
Increased surface exposure. (Score:2)
Re: (Score:2)
That was my initial worry as well, "just how long are those bridges going to last"?
Re: Increased surface exposure. (Score:2)
As long as bones?
Re: (Score:2)
So, order of a hundred years?
Note : you asked about "bones", not fossils. The process of turning a bone (any tissue, really, but most often a bone or a tooth, for a vertebrate) into a fossil is a subject of it's own, stretching in effects from forensic science, through archæology and into regular palæontology Look up "taphonomy".
A 100 year lifetime isn't at all unreasonable for a structure. No structure is eternal (though the Pyramids are making a decent attempt - they'll probably not make it be
Re: Increased surface exposure. (Score:2)
Re: (Score:2)
Building design tends to go for a 2:1 safety margin between expected loads and design strengths. Bridges tend to be a lot more conservative 6:1 or 8:1 between design strength : expected load.
There are good arguments you can have whether a design (and construction process) should have an 8:1 safety margin, or a 6: 1 margin, into which you can easily get a 60% materials cost. If you can justify the lower safety factor and lower cost.
As the Forth road bridge example I just mentioned upthread illustrates, chang
Not to rain on their parade (Score:5, Informative)
But the Romans solved that problem a long time ago.
Roman concrete absorbs CO2 over its lifetime through carbonation, where the hydrated cement reacts with CO2 to form calcium carbonate (calcite).
Because Roman structures can last for millennia, the total duration of this CO2 uptake is extremely long, allowing the process to continue for much longer than the intended service life of most modern concrete (50–120 years and that's generous)
Obviously (Score:2)
They need to dry the filament first
How is it best inspected and repaired? (Score:2)
The most versatile, repairable, recyclable materials for bridges if one can afford them are steels which can be cut, welded, and easily inspected using proven methods then scrapped and recycled efficiently with many of the standard steel sections easy to cut and resell for less critical reuse.
Cheaper concrete destroys reinforcement bars and mats by corrosion which is a major reason why the US infrastructure repair bills are so expensive. (Small and medium bridges can be replaced by portable metal bridging w