Scaling, Map Cracking, Crazing

Map cracking or crazing refers to a network of shallow, fine or hairline cracks that extend only through the upper surface of the concrete. The cracks tend to intersect at angles of approximately 120 deg. Map cracking or crazing usually is caused by concrete over-finishing and may lead to surface scaling, which is the breakdown of the slab surface to a depth of approximately 1/4 to 1/2 in (6 to 13 mm). Scaling also may be caused by deicing salts, improper construction, freeze-thaw cycles and poor aggregate. The type of scaling defined here is not caused by "D" cracking.