Sheepsfoot Drum

The sheepsfoot drum is used for compacting heavy lifts of 6 to 12 inches thick. As consecutive passes are made, the drum will start to walk out of the ground as the penetration of the sheepsfoots decrease. These rollers should only be used for initial compaction, because the footprints they leave will not allow excess water to drain.

These rollers concentrate the static and dynamic weight on the relatively small contact area of the sheepsfoots. This force is exerted through the one row of feet in contact with the ground. With all the roller weight concentrated on this row of sheepsfoots, they exert more than 22,000 pounds of force.

Smooth Drum

In most heavy fills, a smooth drum roller is worked behind the sheepsfoot drum and grader. With thinner

Figure 11-40.-Sheepfoot drum.

Figure 11-41.-Smooth drum.

Figure 11-42.-Pneumatic-tired roller.

lifts, a smooth drum is all the compaction equipment required. The smooth drum compacts lifts of-4 to 8 inches and seals the surface to allow the excess water to drain. Unlike the sheepsfoot drum, smooth drum rollers concentrate the full width of the drum. The total dynamic force is slightly less, because more of the drum is in contact with the ground.