Lightweight Concrete:

Lightweight concrete is build not only on account of its lightweight but also due to high thermal insulation compared with normal concrete.

The self weight of conventional concrete is high. Density of normal concrete varies from 2200 to 2600 kg/m3. Due to heavy weight, conventional concrete becomes an uneconomical structural material to some extent particularly for high rise buildings. A density of lightweight concrete varies from 300 to 1850 kg/m3.

Lightweight concrete is prepared from the subsequent materials.

Binding Material

Different types of cements can be used as binding material. The materials such as lime-slag, lime-cinder, etc. could also be used as binding material.

Aggregates

The loose porous materials are used as aggregates for lightweight concrete. The natural porous aggregates can be obtained by crushing light-weight rocks. The artificial porous aggregates could be acquired from industrial wastes.

Steel

As lightweight concrete is highly porous, the corrosion of reinforcement takes place, if not properly protected. Hence, the lightweight concrete should be made sufficiently dense when used for RCC work. A few times, the reinforcement is coated along with anti-corrosive treatments, when lightweight concrete is used.

Water

The strength of lightweight concrete mainly depends on the amount of water in the concrete mix. The use of potable water is essential to prepare light weight concrete. The water-cement ratio should be carefully calculated to achieve optimum strength of lightweight concrete. While water content reaches its optimum value, there is corresponding increase in the strength of lightweight concrete.