Calcium oxide (CaO)

Calcium oxide, primarily composed of lime, is derived from naturally occurring limestone. It is produced through the calcination of calcium carbonate (CaCO₃) at approximately 1200 ºC.

It’s primarily used in clay soil stabilization, where it modifies the physical properties of the ground by reducing the plasticity index and liquid limit, while increasing CBR and compressive strength. Ionic exchange reactions and calcium silicate formation stabilize fine clay particles, and a useful CaO content above 90% ensures optimal performance. It is also employed in bituminous mixes as a filler substitute, improving water resistance, reducing ageing and cracking, and reinforcing bonds between bitumens and aggregates for durable, homogeneous asphalt layers.