Lightweight concrete, as the name suggests, is a material that is produced by using a variety of lightweight aggregates and the expanding agent. The following are the Lightweight aggregates origin: 1.Natural materials, like volcanic pumice. 2.The thermal treatment of natural raw materials like clay, slate or shale i.e. Leca. 3.Manufacture from industrial by-products such as fly ash, i.e. Lytag. 4.Processing of industrial by-products such as pelletised expanded slab, i.e. Pellite. The expanding agent in that increases the volume of the mixture, which lessens its dead weight. Compared with normal concrete, apart from it is much lighter than conventional concrete, it also has the features of more excellent thermal and sound insulating properties, a good fire rating, non-combustible and cost savings through construction speed and ease of handling.
Classifications of lightweight concrete:
lightweight aggregate concrete--By using porous lightweight aggregate of low apparent specific gravity, i.e. lower than 2.6.
Aerated, cellular, foamed or gas concrete--By introducing large voids within the concrete or mortar mass; these voids should be clearly distinguished from the extremely fine voids produced by air entrainment.
No fines concrete(NFC)--By omitting the fine aggregate from the normal concrete mixture so that there are a large number of interstitial voids forming; usually using normal weight coarse aggregates.
Except for above classification methods, lightweight concrete also can be classified into structural lightweight concrete, masonry lightweight concrete, insulating lightweight concrete according to the purpose for which it is to be used.
Lightweight concrete has extreme importance to the construction industry, ranging from panels and block production, floor and roof screeds, wall casting, complete house casting, sound barrier walls, floating homes, void infill, slope protection, outdoor furniture and many more applications.