Amplitude refers to which property of a roller?

Amplitude in the context of a roller pertains to the vertical motion of the roller during operation, often relating to how much the roller can lift off the ground in a bouncing action. It is a measure of the height at which the roller can jump or vibrate, which is critical in achieving effective compaction on asphalt surfaces.

When a roller with amplitude is in operation, the bouncing effect helps in breaking down air voids within the asphalt mix and ensures better compaction, leading to a smoother and more durable pavement. A higher amplitude can enhance this compaction process by inducing more dynamic forces into the material being compacted.

The other options discuss properties that do not directly pertain to the concept of amplitude. For instance, depth of penetration relates to how deep a roller treads into the material, while width of the roller’s path refers to the area covered during operation, and the total weight informs the compaction pressure but does not involve the vertical movement characteristic defined by amplitude.