15 March 2001
9.1. Purpose of Grinding. Diamond grinding removes faults, reprofiles pavements, removes
surface defects, and restores the pavement to a smooth surface. Because the hardness of the
aggregate will influence the grinding operation, the type of aggregate in the PCC pavement
should be identified when the work is to be contracted.
9.2. Need for Grinding. When a pavement survey reveals surface defects such as faulted joints
in excess of 1/8 inch (3 millimeters), roughness in excess of 1/8 inch (3 millimeters) in a 10-foot
(3-meter) length, or rutting up to 3/8 inch (10 millimeters), diamond grinding should be
considered. If skid resistance is to be examined, it should be examined on the areas not
scheduled for grinding for any of the previously mentioned defects. If a large area requires
grinding to improve skid resistance, economics may favor grinding the entire pavement surface.
9.3. Grinding Process. The diamond grinding process is free of impact and does not damage
joints. The pavement grinder is similar to a wood plane. The front wheels are designed to pass
over a fault or bump, the cutting head shaves it off and the rear wheels ride in a smooth path left
by the cutting head.
Diamond grinding requires heavy, specially designed equipment (Figure 9.1.) that uses diamond
saw blades gang mounted on a cutting head (Figure 9.2.). Spacers are placed between the saw
blades to reduce the amount of cutting that is to be done. This combination of saw blades and
spacers gives the pavement the characteristic corduroy texture that improves skid resistance.
9.4. Test Section. Before work begins, the equipment should be used in a test section to ensure
that proper blade spacing is being used for the specific aggregate on the project. The width of
the spacers between the saw blades is varied depending on the hardness of the aggregates. The