Amazing stuff!
"Since it was invented in the 1980s, 3D printing has moved from the laboratory to the factory, the home and even outer space.
Now, an interdisciplinary group of Cornell researchers is developing a way to bring the technology to the ocean. By 3D-printing concrete underwater, the new approach could transform on-site maritime construction and the repair of critical infrastructure that connects continents. ...
The project got its start in fall 2024, when the Department of Defense’s Defense Advanced Research Projects Agency (DARPA) issued a call for proposals to design 3D-printable concrete that could be deposited at a depth of several meters underwater – and to do so in a radically truncated timeframe of one year. ...
Underwater printing faces numerous challenges. Chief among them is preventing washout, in which cement particles fail to bind together during deposition, weakening the material. The typical solution is introducing admixture chemicals, but these create complications of their own. ...
DARPA added one more hurdle: The concrete needed to consist primarily of seafloor sediment and only include a small amount of cement. Incorporating material from the bottom of the ocean would minimize the logistical difficulty of transporting large quantities of cement by ship. ..."
For months, the team has been conducting test prints in a large tub of water, monitoring how the layers are deposited and the strength, shape and texture of each sample.
