The heavy residue left after crude oil is vacuum distilled, then refined and graded for paving. It makes up only about 5 to 6 percent of a typical mix by weight, yet it controls how the pavement behaves in heat and cold because it is viscoelastic: stiff and brittle when cold, soft and flowing when hot. Binder is bought and specified by performance grade, and its stiffness after aging decides much of a pavement's cracking and rutting life.
Tank's down to forty tons of binder, call the terminal and get another transport of 64-22 headed this way before noon.
Outside North America the same material is called bitumen, and the word asphalt usually means the finished mix.
Also heard as
- binder
- asphalt cement
- bitumen
- liquid asphalt
Do not mix it up with
- Binder course: Binder course is a layer of finished mix in the pavement, not the liquid that glues the mix together.
Related terms
PG
Performance Grade: the binder rating that names the hottest and coldest pavement temperatures a binder can handle.
AC
Asphalt cement: the binder itself, and in pavement design talk, shorthand for the asphalt concrete layer.
Oil
Crew and plant slang for liquid asphalt binder, as in oil content or a load that looks short on oil.
Polymer-modified asphalt
Binder blended with an elastic polymer, usually SBS, to resist rutting in heat and cracking in cold.