A lightweight cementitious composition containing from 10 to 90 volume percent of a cement composition, from 10 to 90 volume percent of particles having an average particle diameter of from 0.2 mm to 8 mm, a bulk density of from 0.03 g/cc to 0.64 g/cc, an aspect ratio of from 1 to 3, and from 10 to 50...http://www.google.de/patents/US20060217464?utm_source=gb-gplus-sharePatent US20060217464 - Lightweight concrete compositions