Rockcrete is a common building material used across the Imperium of Man that is very similar in appearance, texture and usage to ancient Terran materials like concrete. There are many formulations of rockcrete, which provide varied architectural properties, and rockcrete is the most-used man-made product in the galaxy.
It is created by first grinding up a variety of stone and rock types native to the world where the construction will commence. This stone mix is then combined with synthetic binding agents whose recipe is known to the Tech-priests of the Adeptus Mechanicus to produce a quick-drying slurry that can be formed into walls, roofs and flooring of considerable tensile strength and survivability. Rockcrete constructions are used on almost every technologically-advanced Imperial world for one purpose or another.
- Dark Heresy: Inquisitor's Handbook (RPG), pg. 172