UFC 3-260-03
15 Apr 01
(1) Asphaltic cements are readily soluble in jet fuels, but tars are not. Maximum distress is
caused to asphaltic concrete pavements by fuel dripping on a given area at frequent intervals, or by the
pavement mix being sufficiently pervious to allow considerable penetration of the fuel. The voids in the
total mix control the rate at which penetration can occur. Fuel will penetrate very little into pavements
with about 3 percent voids but will rapidly penetrate pavements with high (over 7 percent) voids.
Weathering appears to increase the pavement's resistance to penetration of jet fuels, and pavements
about 1 year or older usually perform better in this respect than new pavements.
(2) The type of binder in the surface course should be determined and the surface course
characteristics evaluated for resistance to jet fuel. The following tabulation will serve as a guide for
evaluating the various types of bituminous pavements from the standpoint of fuel spillage for use in
different areas of the field.
Type Pavement
Texture
Satisfactory for
Asphaltic concrete
Dense
Runway interiors and areas of taxiways where
aircraft do not warm up or stop frequently
Asphaltic concrete
Open
Runway interiors or any high speed areas
Tar and rubberized-tar concrete
Dense
All areas other than refueling pit areas
Note: Rubberized-tar concrete is authorized only in maintenance of existing rubberized-tar concrete
pavements; it is not allowed in new construction.
c.
Ability to Withstand Jet Blast.
(1) Tests have shown that about 149EC (300EF) is the critical temperature for asphaltic con-
crete and rubberized-tar concrete, while the critical temperature for tar concrete is about 121EC (250EF).
Poorly bonded thin layers should be noted. Field tests simulating pretakeoff checks at the ends of run-
ways indicate that the maximum temperatures induced in the pavements when afterburners are not used
are less than 149EC (300EF). Maximum temperatures induced in pavement tests simulating mainte-
nance checkups are 157EC (315EF). Rubberized-tar concretes will usually withstand these
temperatures. None of the bituminous pavements will resist erosion when afterburners are turned on
with the aircraft standing still. When afterburners are turned on after the aircraft has begun the takeoff
run, little or no damage occurs.
(2) Thin-surface courses, not well bonded to the underlying layers, are subject to being
eroded by a high-velocity blast, even though the binder is not melted. All jet aircraft currently in use are
believed to produce blasts of sufficiently high velocity to flay such courses. Surface courses less than
25 millimeters (1 inch) thick and poorly bonded will be considered unsatisfactory for parking areas, and
the 305-meter (1,000-foot) ends of runways will be so reported in the narrative portion of the evaluation
report for all aircraft.
7.
EFFECTS OF TRAFFIC COMPACTION.
a. Paving Mixes. Traffic tends to densify pavements to a certain degree, depending on the gear
loads applied and the characteristics of the mix. Where traffic is widely distributed, densification is
limited; where traffic is channelized, the tendency to densification is greatest. High tire pressures pro-
duce greater densification than low tire pressures. The probability of densification under a given loading
decreases somewhat with pavement age because of hardening of the asphalt. An indication of future
behavior can be obtained from a comparison of the in-place density and void relations of the pavement
with the results of comparable tests on specimens recompacted in the laboratory. If the pavement is
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