Definition
A black, sticky, semi-solid form of petroleum used as the binding agent in paving material. When mixed with crushed stone or gravel and laid in compacted layers, it forms the dark, flexible surface used for many runways, taxiways, and ramps.
Plain English
The black tar-like material that, when mixed with stone, makes the smooth dark surface you see on most runways and taxiways.
Context Anchor
Seen in airport descriptions, runway surface information, taxiway markings, and airport construction or maintenance notices.
Derivation
From the Greek 'asphaltos,' meaning a secure or firm substance. The name reflects what the material does on a runway: it binds the stone together into a firm, stable surface.
Why Pilots Care
Runway surface type influences braking performance, tire wear, and hydroplaning risk during takeoff and landing.
Intuition Check
Asphalt does not mean every paved runway. It means one specific kind of paved surface: blacktop made with a tar-like binder and small stone.
Example Sentence 1
The runway at the small field was asphalt, so the pilot expected softer braking action than on the concrete runway at the airline airport.
Example Sentence 2
The pilot noted the smooth transition from concrete to asphalt on the taxiway.