MIT research on "printing" buildings

MIT News Office posted a survey of the fascinating research at the university, and by alum, on an array of 3D printing technologies and applications.
Another variant underway now is a system being developed by Neri Oxman PhD ’10, the Media Lab’s Sony Corporation Career Development Assistant Professor of Media Arts and Sciences, and her graduate student Steven Keating for “printing” concrete. Their ultimate aim: printing a complete structure, even a whole building.

Why do that, instead of the tried-and-true method of casting concrete in wooden forms that dates from the heyday of the Roman Empire? In part, Oxman explains, because it opens up new possibilities in both form and function. Not only would it be possible to create fanciful, organic-looking shapes that would be difficult or impossible using molds, but the technique could also allow the properties of the concrete itself to vary continuously, producing structures that are both lighter and stronger than conventional concrete.

To illustrate this, Keating uses the example of a palm tree compared to a typical structural column. In a concrete column, the properties of the material are constant, resulting in a very heavy structure. But a palm tree’s trunk varies: denser at the outside and lighter toward the center. As part of his thesis research, he has already made sections of concrete with the same kind of variations of density.

“Nature always uses graded materials,” Keating says. Bone, for example, consists of “a hard, dense outer shell, and an interior of spongy material. It gives you a high strength-to-weight ratio. You don’t see that in man-made materials.” Not yet, at least.

"Printing off the paper"