Scaling

ASTM D5340 defines scaling as a surface deterioration caused by construction defects, material defects and environmental factors. Generally scaling is exhibited by delamination or disintegration of the slab surface to the depth of the defect. Construction defects include: over-finishing, addition of water to the pavement surface during finishing, lack of curing, and attempted surface repairs of fresh concrete with mortar. ASTM further explains that construction defects generally occur over a portion of a slab. Material defects include: inadequate air entrainment for the climate. This defect usually occurs within a batch and may affect several slabs. Environmental factors include: freezing of concrete before adequate strength is gained or thermal cycles from specific aircraft. These defects may occur over an entire pavement in the case of freezing or isolated areas in the case of thermal effects.

Severity	Distress Example	Description
Low		Minimal loss of the surface paste that poses no FOD hazard. No FOD potential, limited to less than 1% of the slab area.
Medium		The loss of surface paste that poses some FOD potential including isolated fragments of loose mortar, exposure of the sides of coarse aggregate (Less than ¼ of the width of coarse aggregate), or evidence of coarse aggregate coming loose from the surface. Surface paste loss is greater than 1% of the slab area but less than 10%.
High		High-severity scaling is associated with low durability concrete that will continue to pose a high FOD hazard; normally the layer of the surface mortar is observable at the perimeter of the scaled area, and is likely to continue to delaminate or disintegrate due to environmental and other factors. Routine sweeping is not sufficient to avoid FOD issues, is an indication that high FOD hazard is present. Surface paste loss is greater than 10% of the slab area.