Cellular lightweight concrete: materials, applications and advantages

Cellular lightweight concrete (CLC), also known as foamed concrete, is manufactured by combining Portland cement, sand, fly ash, water and preformed foam in varying proportions. This material offers a number of advantages over traditional concrete bricks for construction applications.

Structure of cellular lightweight concrete

CLC is made up of three primary components.

• Foam: generated by foam generators using appropriate agents, making up 40 to 80 percent of total volume, with bubble sizes ranging from 0.1 to 1.5 mm in diameter.

• Fly ash: an industrial waste product that addresses disposal challenges while enhancing the material's environmental friendliness and economic viability.

• Cement: combines Portland cement with silica, pozzolana or lime based pastes, creating a homogenous structure with consistent cell formation.

Manufacturing process

• CLC batches are produced by mixing raw materials in concrete mixers, with strength varying based on material composition and air pocket content.

• Continuous production involves mixing light mortar with preformed foam under pressure using special static mixers.

Density ranges

Regular concrete has a density of 2,400 kg/m³, while foamed concrete ranges from 400 to 1,800 kg/m³.

• Lower density, 400 to 600 kg/m³: thermal and sound insulation, fire, termite and moisture resistant.

• Medium density, 800 to 1,000 kg/m³: non-load bearing precast blocks.

• High density, 1,200 to 1,800 kg/m³: structural applications for load bearing walls and ceilings.

Key advantages

• Lightweight construction reduces structural load

• Fire resistant due to air pockets within the structure

• Excellent thermal insulation properties

• Sound absorption and acoustic insulation capabilities

• Environmentally friendly through waste utilisation

• Cost effective production and installation

• Termite proof and resistant to freezing issues

Applications

• Thermal insulation for flat roofs and non-load bearing walls

• Renovation of old sewer pipes and wells

• Heat insulated wall panels

• Acoustic balance maintenance

• Ceramic tile production

• Soil water drainage systems

• Bridge construction to prevent freezing

• Perlite plaster and lightweight concrete alternatives

Distinction from aerated concrete

Unlike aerated concrete, which forms bubbles chemically through aluminium powder reactions, CLC uses a distinct manufacturing technique based on preformed foam, resulting in different properties suited to various construction requirements.