15 March 2001
DISTRESS 64, DURABILITY ("D") CRACKING
6.1. Description. Durability cracking is caused by the inability of the concrete to withstand
environmental factors such as freeze-thaw cycles. It usually appears as a pattern of cracks
running parallel to a joint or linear crack. A dark coloring can usually be seen around the fine
durability cracks. This type of cracking may eventually lead to disintegration of the concrete within
1 to 2 feet (0.3 to 0.6 meter) of the joint or crack. Deduct curves for durability cracking are shown
in Figure 6.1.
6.2. Severity Levels.
6.2.1. L. "D" cracking is defined by hairline cracks occurring in a limited area of the slab, such
as one or two corners or along one joint. Little or no disintegration has occurred. No FOD
potential (Figures 6.2. and 6.3.).
6.2.2. M. (1) "D" cracking has developed over a considerable amount of slab area with little or
no disintegration or FOD potential; or (2) "D" cracking has occurred in a limited area of the slab,
such as in one or two corners or along one joint, but pieces are missing and disintegration has
occurred. Some FOD potential (Figures 6.4. and 6.5.).
6.2.3. H. "D" cracking has developed over a considerable amount of slab area with
disintegration of FOD potential (Figures 6.6. and 6.7.).
6.3. How to Count. When the distress is located and rated at one severity, it is counted as one
slab. If more than one severity level is found, the slab is counted as having the higher severity
distress. If "D" cracking is counted, scaling on the same slab should not be recorded.