TM 5-826-6/AFR 93-5
f. Jet blast erosion, distress 46.
(1) Description. Jet blast erosion causes darkened areas on the pavement surface where bituminous binder
has been burned or carbonized. Localized burned areas may vary in depth up to approximately 1/2 inch.
(2) Severity levels. No degrees of severity are defined. It is sufficient to indicate that jet blast erosion exists
(figs. A-21 and A-22).
Figure A-21. Jet blast erosion, case 1.
Figure A-22. Jet blast erosion, case 2.
(3) Measuring procedure. Jet blast erosion is measured in square feet of surface area.
Joint reflection cracking from PCC (longitudinal and transverse), distress 47.
(1) Description. This distress occurs only on pavements having an asphalt or tar surface over a portland
cement concrete (PCC) slab. This category does not include reflection cracking from any other type of base (i.e., cement
stabilized, lime stabilized). Such cracks are listed as longitudinal and transverse cracks. Joint reflection cracking is
caused mainly by movement of the PCC slab beneath the AC surface because of thermal and moisture changes. It is not
load-related. However, traffic loading may cause a breakdown of the AC near the crack, resulting in spalling and FOD
potential. If the pavement is fragmented along a crack, the crack