The concrete which has substantially lower mass per unit volume then the concrete made of ordinary ingredients is called lightweight concrete. The aggregates used are lighter in weight.
Density of light weight concrete is 240 kg/m³ (15pcf) -1850 kg/m³ (115 pcf).
Strength of light weight concrete blocks varies from 7 MPa (1000 psi) – 40 MPa (5800 psi).
Some times Air Entrained Admixtures are also added to it giving resistance to freezing and thawing along with strength.
Uses of Light weight concrete:
Used where extra load is not applied e.g. parapet wall, road lining etc. or to reduce dead load.