Bleeding

Description

A film of asphalt binder on the pavement surface. It usually creates a shiny, glass-like reflecting surface (as in the first photo) that can become quite sticky. Sometimes referred to as "flushing".

Problem

Loss of skid resistance when wet

Possible Causes

Bleeding occurs when asphalt binder fills the aggregate voids during hot weather and then expands onto the pavement surface. Since bleeding is not reversible during cold weather, asphalt binder will accumulate on the pavement surface over time. This can be caused by one or a combination of the following:

• Excessive asphalt binder in the HMA (either due to mix design or manufacturing)
• Excessive application of asphalt binder during BST application (as in the above figures)
• Low HMA air void content (e.g., not enough room for the asphalt to expand into during hot weather)

Repair

The following repair measures may eliminate or reduce the asphalt binder film on the pavement's surface but may not correct the underlying problem that caused the bleeding:

• Minor bleeding can often be corrected by applying coarse sand to blot up the excess asphalt binder.
• Major bleeding can be corrected by cutting off excess asphalt with a motor grader or removing it with a heater planer. If the resulting surface is excessively rough, resurfacing may be necessary (APAI, no date given).

@misc{pavint-bleeding,
  author = {{Pavement Interactive}},
  title = {Bleeding},
  year = {2018},
  publisher = {HeadLight},
  howpublished = {\url{https://pavementinteractive.org/reference-desk/pavement-management/pavement-distresses/bleeding/}},
  note = {Accessed [date]}
}