Flushing (also Bleeding) is the partial or complete immersion of aggregate into the bituminous binder causing low texture depth and inadequate skid resistance.


Alternate Definitions

A pavement surface defect in which binder is near the top of the aggregate particles. There is minimal surface texture. In severe cases the bitumen covers the aggregate - Austroads Glossary of Terms.


Flushing occurs when the available void volume in a seal is insufficient to accommodate the volume of bitumen, aggregate fines and other detritus
present. One theory is that loss of void volume leading to flushing is primarily a result of the build-up of fine (<4.75 mm) aggregate particles produced by wear and breakdown of sealing aggregate during construction and under traffic.2

Related Pages

External Links & References

  1. Pavement Guide Interactive
  2. Aggregate Breakdown as a Cause of Chip Seal Flushing (Herrington, Ball, Patrick & Towler)
  3. Beeding Seals & Pavement Preparation (Walter Holtrop)
  4. Google Search
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