Aerated concrete is one of a group of materials described collectively as 'lightweight concrete.' The term 'lightweight concrete' is somewhat arbitrary; in the past it has been customary to consider as 'lightweight, any concrete of dry density not exceeding
100 Ib/cu. ft., but the use of reinforced units has led to concretes with a density of 110-115 or even to 120 Ib/cu. ft.
A. Short and W. Kinniburgh