"Foamed concrete is also referred to as aerated or cellular concrete. Foamed concretes are lightweight concretes [typically... with densities ranging from 320 to 1,920 kg/m3 (20 to 120 lb/ft3)] that are prepared by adding air cells... typically... from 0.1 to 1 mm (0.004 to 0.04 in.) in diameter (Aldrich and Mitchell 1976)."