UFC 3-270-02
15 March 2001
CHAPTER 9
CRACK SEALING PROCEDURES
9.1. Crack Size Guidelines. Procedures for sealing will vary depending upon the size of the
crack. The following should be used as a guide.
9.1.1. Hairline cracks (less than 1/4 inch (6 millimeters)). It is very difficult to successfully insert
sealant material into a crack that is less than 1/4 inch (6 millimeters). Normally, these cracks are
not sealed unless they cover 80 percent or more of the pavement area. If the cracks do require
sealing, a surface treatment could be the most effective method. The surface treatment used will
depend upon the area being treated and the predicted future traffic. A single or double
bituminous surface treatment could be satisfactory for a roadway or parking lot, but not for an
airfield. Surface treatments and slurry seals are not recommended for airfields that will encounter
jet and high-tire-pressure aircraft because the surface treatment or slurry seal will normally
deteriorate quickly. Options such as an asphalt overlay or pavement recycling should be
considered for airfield pavements. For additional information on various types of surface
treatments, see Department of the Navy, NFGS-02788B, NFGS-02789B, NFGS-02787B;
Department of the Army, Corps of Engineers CEGS-02745; or Departments of the Army and Air
Force TM 5-822-8/AFM 88-6, Chapter 9.
9.1.2. Small and medium cracks (1/4 to 2 inches (6 to 50 millimeters)). After the crack has been
cleaned and inspected, it is ready for sealing. The depth of the cracks to be sealed is determined
and, if the depth is greater than 3/4 inch (19 millimeters), a backer rod material is inserted. If the
depth of the crack is not deep enough to accommodate the backer rod and maintain a sealant
depth of 1/2 to 3/4 inch (13 to 19 millimeters), then the crack can be routed or the backer rod
material omitted.
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