Tampers, sometimes called jitterbugs, push the coarse aggregate in concrete below the surface to consolidate it. Which device is described?

• A. Finisher
• B. Roller tamper
• C. Tampers
• D. Vibrator

Answer: (C)

Tamping is a manual way to consolidate freshly placed concrete by physically pressing the mix so the aggregates settle and voids are filled. Tampers, or jitterbugs, are designed for this job; you use the tool to push the coarse aggregate down and pack the surrounding paste, creating a denser, more uniform section. This is different from vibration, which uses oscillation to make the concrete flow and expel air throughout the mass. A roller tamper is used for soil compaction, and a finisher or vibrator has other roles in finishing surfaces or vibrating the concrete, not the specific downward packing of the aggregate described here.