Fly ash cellular lightweight concrete: properties and uses

Cellular lightweight concrete (CLC) is an emerging construction technology that offers advantages over conventional concrete. By incorporating fly ash, a thermal power plant waste product, CLC addresses disposal challenges while reducing construction costs and environmental impact through low energy production.

Overview of fly ash CLC

Cellular lightweight concrete is one of the more recent technologies used in making concrete. The material combines cement, sand, fly ash (26 to 34 percent content) and water. Using a foam generator creates the distinctive cellular structure. Density ranges from 400 to 1,800 kg/m³, with strength comparable to normal concrete despite the lighter weight.

Composition and manufacturing

CLC is an air cured lightweight concrete with fly ash as its main ingredient, and it can be produced at large project sites in the same way as traditional concrete. The manufacturing process does not require complicated techniques, and uses standard equipment and moulds. Production saves approximately 40 percent of cement while making use of waste fly ash material.

Density applications

• Lower densities, 400 to 600 kg/m³: thermal insulation, fire and termite resistant barriers, sound insulating layers.

• Medium density, 800 to 1,000 kg/m³: non-load bearing partition blocks, typically 500 x 250 x 200 mm or 500 x 250 x 100 mm.

• High density, 1,200 to 1,800 kg/m³: load bearing structural walls, reinforced panels, low rise construction.

Key properties

• Low weight

• Fire resistance

• Thermal insulation

• Sound absorption

• Negligible thermal expansion

• Minimal spalling tendency

Primary uses

• Partition wall construction

• Thermal insulation applications

• Hollow filled floor systems