UFC 3-270-02
15 March 2001
CHAPTER 7
CRACK PREPARATION PROCEDURES
7.1. Crack Size Guidelines. Crack preparation procedures depend on crack size. The following
information should be used as a guide when preparing cracks for sealing.
7.1.1. Hairline cracks (less than 1/4 inch (6 millimeters)). Hairline cracks (Figure 7.1.) require no
preparation (see Chapter 9).
7.1.2. Small cracks (1/4 to 3/4 inch (6 to 19 millimeters)). Small cracks (Figure 7.2.) should be
widened to a nominal width of 1/8 inch (3 millimeters) greater than the existing nominal or
average width. Widening the cracks 1/8 inch (3 millimeters) will help eliminate the potential for
raveling of the pavement along the edges of the crack and will provide a sealant reservoir that
has vertical faces. The depth of the routed crack should be approximately 3/4 inch
(19 millimeters). A backer rod material (see Chapter 9) should be placed in cracks that have a
depth greater than 3/4 inch (19 millimeters). Backer rod materials are not required in cracks that
are 3/4 inch (19 millimeters) deep.
7.1.3. Medium cracks (3/4 to 2 inches (19 to 50 millimeters)). Cracks that are 3/4 to 2 inches
(19 to 50 millimeters) (Figure 7.3.) shall be prepared by simply cleaning the crack using a
sandblaster, HCA heat lance, or wire brushes, and then cleaning with compressed air. The crack
must be inspected to ensure that it is clean and dry.
7.1.4. Large cracks (greater than 2 inches (50 millimeters)). Cracks wider than 2 inches
(50 millimeters) (Figure 7.4.) should be prepared in the same manner as potholes. A saw should
be used to cut away damaged pavement to provide vertical faces. The area should then be
cleaned and filled instead of sealed (see Chapter 9).
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