UFC 3-270-05
15 March 2001
CHAPTER 4
DISTRESS 62, CORNER BREAK
4.1. Description. A corner break is a crack that intersects the joints at a distance less than or
equal to one-half the slab length on both sides, measured from the corner of the slab. For
example, a slab with dimensions of 25 by 25 feet (7.5 by 7.5 meters) that has a crack intersecting
the joint 5 feet (1.5 meters) from the corner on one side and 17 feet (5.1 meters) on the other side
is not considered a corner break; it is a diagonal crack. However, a crack that intersects 7 feet
(2.1 meters) on one side and 10 feet (3 meters) on the other is considered a corner break. A
corner break differs from a corner spall in that the crack extends vertically through the entire slab
thickness, while a corner spall intersects the joint at an angle. Load repetition combined with loss
of support and curling stresses usually causes corner breaks. Deduct curves for corner breaks
are shown in Figure 4.1.
4.2. Severity Levels.
4.2.1. L. Crack has either no spalling or minor spalling (no foreign object damage (FOD)
potential). If nonfilled, it has a mean width less than approximately 1/8 inch (3.2 millimeters); a
filled crack can be of any width, but the filler material must be in satisfactory condition. The area
between the corner break and the joints is not cracked (Figures 4.2. and 4.3.).
4.2.2. M. One of the following conditions exists: (1) filled or nonfilled crack is moderately
spalled (some FOD potential); (2) a nonfilled crack has a mean width between 1/8 inch
(3.2 millimeters) and 1 inch (25.4 millimeters); (3) a filled crack is not spalled or only lightly
spalled, but the filler is in unsatisfactory condition; (4) the area between the corner break and the
joints is lightly cracked with loose or missing particles (Figures 4.4. and 4.5.).
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