The document discusses lightweight concrete, including its production, properties, and applications. Lightweight concrete has a density ranging from 300kg/m3 to 1850kg/m3, which is achieved through the inclusion of air into its composition. This can be done by replacing normal aggregate with hollow, cellular, or porous aggregate that contains voids. Lightweight concrete offers benefits like reduced self-weight, increased productivity, better thermal insulation, seismic resistance, and fire protection compared to normal concrete. It can be classified based on its intended use, such as structural, non-load bearing walls, or insulation purposes.