TM 5-826-6/AFR 93-5
k. Polished aggregate, distress 51.
(1) Description. Aggregate polishing is caused by repeated traffic applications. Polished aggregate is present
when close examination of a pavement reveals that the portion of aggregate extending above the asphalt is either very
small or there are no rough or angular aggregate particles to provide good skid resistance.
(2) Severity levels. No degrees of severity are defined. Polished aggregate should not be counted unless
detected on a runway or high speed taxiway and the degree of polishing should be significant before it is included in the
condition survey and rated as a defect (fig. A-41).
Figure A-41. Polished aggregate.
(3) Measuring procedure. Polished aggregate is measured in square feet of surface area.
l. Raveling and weathering, distress 52.
(1) Description. Raveling and weathering are the wearing away of the pavement surface caused by the
dislodging of aggregate particles and loss of asphalt or tar binder. They may indicate that the asphalt binder has hardened
significantly.
(2) Severity levels.
(a) Low severity level (L).
- Aggregate or binder has started to wear away with few, if any, loose particles causing little or no FOD
potential (figs. A-42 and A-43).
- For porous friction courses, most of the fine aggregate (passing through the No. 4 sieve, i.e., less
than 1/4 inch), have been lost and only a few of the larger pieces have been dislodged, causing little
or no FOD potential (figs. A-44 through A-46).
A-27
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