Lightweight concrete is a type of concrete that has a density that is 25% to 50% lower than normal concrete. It is used for filling voids, leveling floors, and backfilling around ducts or cables in new or old buildings.

The lightweight aggregates that are used in this concrete are porous and voidy, which helps to decrease the weight of the concrete. Typical lightweight aggregates include pumice, thermally treated shale, diatomite, scoria, and volcanic cinder.

These lightweight aggregates are injected into the concrete during mixing to form air voids or entrainment, which increases the volume of the concrete and decreases its density. The voids help the concrete to hydrate faster, which leads to less cracking, spalling, and fire resistance.

Another common way to create lightweight concrete is to use aluminum powder. This will react with calcium hydroxide to produce hydrogen gas, which forms a bubble of air within the concrete mix.

This will increase the strength of the concrete. A lightweight concrete with aluminum powder in it is often called foamed concrete. It also exhibits appropriate thermal insulation, self-compaction, and does not require flattening.

Maxrete lightweight insulating concrete is designed using natural lightweight clay aggregates, cement and admixtures that offer excellent performance for indoor and outdoor applications including filling voids, levelling floors or slopes, backfilling around ducts, cables and pipework. The lightweight aggregates, insulating cement and admixtures work together to make this product four times lighter than traditional concrete or screed.