Asphalt component (3)
I believe the answer is:
tar
'asphalt component' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tar that I've seen before include "Sailor - laid on road" , "Black substance, used on roads" , "Tobacco residue; sailor" , "It paves the way" , "Sticky substance - seaman" .)