By Bryant Jordan
Add to guns and prosthetic hands something much bigger and heavier forming from the nozzle of a 3D printer — buildings “printed” out of concrete.
Partially funded by the Office of Naval Research and the National Science Foundation Countour Crafting is trying to develop 3D printed buildings using concrete. Company founder Behrokh Khoshnevis is a professor and director of Manufacturing Engineering Graduate Program at the University of Southern California.
Concrete printers would be able to build a 2,500-square-foot building within a single day, according to Khoshnevis.
For the military, that means soldiers deploying to a remote location with little or no infrastructure could be operating out of permanent structures pretty soon after a combat engineer unit arrived with printers and material aboard a C-17.
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Essentially, building via printer would work just like any computer assisted manufacturing program. But instead of a robotic tap and die machine turning out parts according to a program, it would be an oversized printer following programmed schematics to lay down, layer by layer, a building, including outside and interior walls, spaces for doors and windows and all electrical, plumbing and air-conditioning conduits, according to Khoshnevis’ website.
In a video of a presentation he made last year Khoshnevis says the machines he is working with now are capable of printing out concrete walls able to bear a compressive stress of 10,000 pounds per square inch. According to the Portland Concrete Association, which represents concrete manufacturers nationwide, conventional concrete has a psi of 7,000 or less.
Anything above that, up to 14,500 psi, is considered high strength.
Building construction is about the only thing that is not automated today, Khoshnevis says. At the same time it kills about 10,000 people a year and injures about 400,000.
Given the history of U.S. military and related missions in Iraq and Afghanistan, Khoshnevis observations on other aspects of conventional construction should also have meaning to the Pentagon.
“The [existing] process is pretty corruption prone,” he said. “It’s very costly and always over budget.”
Looking even further ahead, and farther away, Khoshnevis says 3D construction is likely the solution to be “one of the very few feasible approaches for building structures on the Moon and Mars, which are being targeted for human colonization before the end of the new century.”