Leca (Clay Ball) is a lightweight aggregate produced by foaming in a rotary kiln. It has a spherical shape, a smooth and hard surface, and a honeycomb like interior, characterized by low density, low thermal conductivity, and high strength. In the refractory material industry, ceramic particles are mainly used as aggregates for thermal insulation refractory materials.

The bulk density of ceramic particles themselves is less than 1100kg/m3, generally ranging from 300 to 900kg/m3. The density of concrete made with ceramic aggregate is 1100-1800kg/m3, and the corresponding compressive strength of concrete is 30.5-40.0Mpa. The biggest feature of ceramic particles is that these have a hard surface and numerous micropores inside.