15 March 2001
5.1. Description. The recommended method for preparing cracks with no raveling along the
edges is to saw the crack with a small-diameter blade or route it to the proper depth and width for
the particular sealant and use backer rods. Each face of the sawcut or routed crack must be
sandblasted. The crack faces are then cleaned with high-pressure water and air and the area
swept with a vacuum-broom to prevent the material from reentering the sawed crack. Small
sections of repair are made at a time to prevent the sawed crack faces from being exposed to the
elements for more than 24 hours. If the cracks are wet, they must be dried with a hot-air lance or
high-pressure air compressor equipped with an operating water and oil separator before placing
the sealant and backer rod. The sealant must conform to the applicable ASTM specifications and
must be approved for use at a particular facility by the base engineer. The sealant is placed in
the crack from the bottom up and in one smooth run from the beginning to the end of the crack.
The crack must be filled to a depth of 1/8 to 1/4 inch (3 to 6 millimeters) for conventional sealant
(Reference 1.3.3.) and 1/4 to 3/8 inch (6 to 9 millimeters) for silicone sealant below the surface of
the pavement (Reference 1.3.4.).
5.2. Test Section. A test section of approximately 200 linear feet (61 meters) of cracks must be
sealed and approved by the Contracting Officer before beginning the full crack sealing project.
The same procedures and materials to be used in the full project must be used in the test section.
Crack sawing or routing should be shown not to cause spalling. The crack faces must be clean
before placement of any sealant. For two-component sealants, the correct mixing ratio must be
verified to be within a specified tolerance according to the manufacturer's specifications for that
particular sealant. If using hot-applied sealants, calibrated thermometers must be used to verify
correct application temperatures. All equipment must be shown to be in good working condition