Some months ago we reported on a really large 3D printing operation: Contour Crafting. This company is building a building-sized 3D printer. What for? Printing buildings, of course! The device (a large sized industrial machine) is essentially a gigantic 3D printer that uses concrete as its print media. By printing the digitized model of a house, you get, well, a house!
Meshverse recently uncovered a video report on the progress of the company and an overview of their technology - including mention of their very special concrete mix.