Asphalt, also known as bitumen or tar, is a black almost solid form of petroleum which is found as a natural deposit or which can be refined from crude oil.
Asphalt was originally mixed with stone to form bituminous macadam and used for road surfacing. Bituminous macadam was shortened to bitmac, which includes many forms of tarmacadam and stone mastic asphalt or SMA.
In common usage, asphalt paving is more commonly referred to as stone mastic asphalt.
Although tarmacadam was developed in the UK in the early part of the twentieth century, for road use it was superseded by stone mastic asphalt which is a much harder product.
This is because SMA consists of up to 80% stone which creates a durable aggregate skeleton designed to take heavy goods vehicles (HGVs) without rutting and deformation.
Stone Mastic Asphalt was developed in Germany in the 1960s. It has a much higher proportion of stone than tarmacadam, which produces a more durable and stable paving material.
Asphalt paving, or stone mastic asphalt is ideal for roads, car parks and industrial estates which take regular heavy traffic.