A film of excess binder on the surface, usually in the wheel paths, that looks glossy black, softens and tracks in hot weather, and loses skid resistance in rain. It happens when the mix has too much binder or too few air voids, so traffic squeezes binder upward, and it can also come from too much tack or a fat chip seal. Many people use flushing for the milder, less sticky version.
Bleeding in both wheel paths on the climbing lane, plant voids were under three the whole week we paved it.
Also heard as
- flushing
Related terms
Fat
Describes mix carrying too much binder: shiny, slick and prone to bleeding or rutting.
Air voids
The small pockets of air between binder-coated aggregate in compacted mix, given as a percent of total volume.
VFA
Voids filled with asphalt: the share of the aggregate voids occupied by binder rather than air.
Tack coat
A thin spray of asphalt between layers that bonds the new lift to the surface underneath.