Which of the following describes when high amplitude is used on Vibratory Rollers?

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The main idea is that the vibration energy you apply with a roller is chosen to match the material you’re compacting and how deep the lift is. High amplitude provides more vertical compaction energy, which helps coarse, stiff materials densify when you’re dealing with thicker lifts. Coarse aggregate needs that extra energy to rearrange and interlock, especially when you’re compacting lifts over about two inches.

If you use high amplitude on fine materials like sand or asphalt, or on very thin lifts, you risk excessive movement, segregation of fines, surface damage, or tearing. In those cases, a lower amplitude is preferable to achieve a smooth, uniform finish.

So, high amplitude is best when compacting coarse aggregate with lifts over 2 inches, because it delivers the necessary energy to properly densify that material at that depth.