This tag is used for objects with asphalt concrete surface (commonly abbreviated to asphalt) - for example roads or sports fields (leisure=pitch).
You may add asphalt:type=* to indicate a more specific type of asphalt.
This surface is known as "asphalt, blacktop, or pavement in North America, and tarmac or bitumen macadam in the United Kingdom and the Republic of Ireland"[1]
Sport Use
surface=asphalt is commonly used on leisure=pitch elements. Basketball pitches are the most common sport use, followed by soccer and handball.[2]