UFC 3-270-02
15 March 2001
damaging the effectiveness of the seal. However, if the shape factor is too small, adhesion
failure can occur; therefore, it is important to maintain the proper shape factor.
9.3. Inspection Prior to Sealing. The cracks should be inspected immediately prior to sealing.
This will ensure that the backer rod is at the specified depth and that debris has not been blown
back into the crack. Clean cracks are essential in obtaining adhesion between the sealant and
the crack face.
9.4. Sealant Temperature and Application. The temperature of the sealant should be checked
to make sure it is at the manufacturer's recommended application temperature. The nozzle of the
application equipment is inserted into the crack, allowing the crack to be sealed from the bottom
to the top (Figure 9-3). Sealing in this manner minimizes bubbling of the sealant due to
entrapped air. The sealant should be recessed approximately 1/8 to 1/4 inch (3 to 6 millimeters)
below the pavement surface to prevent tracking. A squeegee may be used to remove excess
sealant from the pavement surface when a crack is overfilled (Figure 9-4).
9.5. Crack Sealing Delays. Any cracks that are not sealed the same day they are prepared
should be blown out with compressed air before the sealing operation continues. If rain delays
the sealing operation, the cracks should be allowed to dry and may require additional cleaning to
remove any debris that may have been washed into the crack by rain. This debris can be
effectively removed by the sandblaster, wire brushes, or HCA heat lance, but not by using only
compressed-air cleaning.
9.6. Inspection After Sealing. After the cracks have been sealed (Figure 9.5.), they should be
inspected to ensure the sealant is bonding to the pavement and that the cracks were not
overfilled. Overfilled material can track onto the pavement surface and/or stick to pedestrians'
shoes. The sealant should also be inspected to ensure the proper sealant recess has been
obtained. Sealants that have not been recessed may be pushed above the pavement surface as
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