Lightweight aggregate concrete, as the name suggests, is a material that is produced by using a variety of lightweight aggregates. Lightweight aggregates originate from either:
Natural lightweight aggregate: Pumice, Scoria, Rice husk, Diatomite, Volcanic tuff, Foamed lava, etc.
Artificial lightweight aggregate: Sintered fly ash, Foamed slag, Bloated clay, Artificial cinders, Expanded clay, slate, shale, Coke breeze, Expanded perlite, Exfoliated vermiculite, etc.
Natural lightweight aggregate is less preferred over the artificial lightweight aggregate.
Lightweight aggregate concretes can be used for structural applications, with strengths equivalent to normal weight concrete, particularly where the need to reduce weight in a structure was in a structure was an important consideration for design or for economy.
Using lightweight aggregate concrete has the following advantages:
Savings in foundations and reinforcement owing to dead loads reduction;
Improved thermal properties and fire resistance;
Reduction in formwork and propping;
The elastic modulus of lightweight concretes is lower than the equivalent strength normal weight concrete, but when considering the deflection of a slab or beam, this is counteracted by the reduced self-weight.