Rolling Operations

When needed, a major part of the construction of a RCC pavement is the rolling operation (see roller pattern in figure 9), which typically consists of initial compaction and then finished rolling. Initial compaction usually is done with a 10- to 12-ton vibratory roller. While the roll pattern is being established, the density is checked on a regular basis. The roll pattern is adjusted according to the moisture content of the mixture, but the goal is to achieve at least 98 percent density.

Density typically is tested using a nuclear gauge and taken behind the paver after rolling has been completed to validate the performance of the paver and to confirm that the rolling complies with the minimum 98 percent density specification. Large changes in the mixture moisture content lead to changes in compactability and final smoothness of the pavement surface. Strength specimens are also prepared following ASTM C 1435 using a vibratory hammer and standard sized compression cylinders. Finer gradations tend to achieve the target density at a lower compactive effort.

Finish rolling is normally done with a 3- to 6-ton roller and can be a combination of dual steel or rubber tired rolling. The goal of the finish rolling is to remove roller marks from the surface.