Bottom ash is often used in unbound applications as light weight material in civil engineering because of its low density and good drainage capacity. In addition, it is used as an aggregate to produce concrete blocks, where it primarily replaces sand.
It is also used as a sub layer in sports fields that are equipped with artificial turf. This 7 cm thick sub layer consists of a mixture of ground tires and bottom ash. The layer is permeable and a shock absorbent, which are attractive qualities to avoid sports injuries.