15 May 2001
it may be significant for runways or other areas where high aircraft speeds are likely to occur. Extreme
caution must be exercised when applying rejuvenators to areas subject to high-speed traffic.
(c) A rejuvenator should not be applied to pavement having an excess of binder on the
surface such as that found in a slurry seal, porous friction course, or surface treatment. When excessive
binder is on the surface, the rejuvenator will soften the binder and cause the surface to become tacky
(d) The amount of air voids in the asphalt mixture being rejuvenated should be at least
5 percent to ensure proper penetration of the rejuvenator into the pavement. If the voids are less than
5 percent, the rejuvenator may fill the voids and thus cause an unstable mix.
(e) Care must be used in selecting a rejuvenator. Some rejuvenators perform satisfactorily,
but many do not. The rejuvenator selected for use should have a proven record of satisfactory
performance. However, if performance data on a particular rejuvenator are not available, the
rejuvenator should be applied to a test area on the pavement and evaluated over some period of time to
determine its potential performance.
(f) It is desirable to improve the existing properties of the asphalt cement in the top
5 millimeter (1/4-inch) or more of the pavement so that the asphalt cement approaches its original
properties. Test results have shown that the viscosity test is more effective in determining a change in
asphalt properties than the penetration test. While the application of a small amount of rejuvenator will
be reflected by the viscosity test, the penetration test may indicate very little or no change in asphalt
(g) Rejuvenators should be applied in hot weather, above 21 degrees C (70 degrees F), so
that the rejuvenator will penetrate more deeply into the asphalt pavement and will cure sooner.
(2) Application of rejuvenators. When applying a rejuvenator, the following must be considered.
(a) The asphalt distributor is the key piece of equipment used to apply asphalt rejuvenators.
It is essential that the distributor is in proper operating condition when rejuvenators are applied to ensure
that the rate of application is uniform. An inspection of the distributor should ensure that:
 The distributor has a circulating tank so that the rejuvenator can be thoroughly mixed
prior to spraying.
 The motor is in proper running condition so that it does not misfire when accelerating
and cause varying rates of rejuvenator to be applied.
 The size of the spray nozzles is selected so that a smooth consistent spray is
obtained over the range of desired application rates.
 All spray nozzles are the same size and are set at the same angle with the spray
 The spray bar is at the correct height to provide either a double or triple overlap.
 The application rate is checked to verify proper calibration.
(b) Before the rejuvenator is applied to the pavement, several test sections should be
constructed and the rejuvenator should be applied to the sections at various rates to determine the