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When you're on the open road paving highways, or even on secondary roads, large ride-on compactors can't be beat for productivity and cost-effectiveness. But for small repair jobs or in confined areas, such as parking lots with concrete islands, or on smaller walkways and paths, walk-behind compactors are tailor made for keeping the job on track.

Even roadway jobs often include areas where it's difficult or impossible to use a large compactor, around sewer grates for example, so it generally pays to have at least one walk-behind compactor on your truck.

Compaction increases the load-bearing capacity and durability of hot mix asphalt paved surfaces by eliminating air voids and removing moisture from asphalt and its underlying materials. It also improves pavement rideability, or smoothness. The type of material you're compacting, as well as the size of the job, will dictate which walk-behind compactor is best suited — a roller or plate model, a larger or smaller machine, with or without vibration.

The role of vibration

Compacting granular material such as aggregate requires vibratory force. The vibration frequency moves particles around until they settle, like puzzle pieces, in their densest format with small particles locking the large ones in place. Even finer particles, which don't vibrate as well, require impact force to squeeze moisture out of the material.

"Vibration is the most important part of compacting," says Peter Price, product manager-light equipment at BOMAG Americas Inc. "It's only when you're using a compactor on asphalt for the finishing process, for smoothness — or when the pavement has a very small lift — that you can rely on the static weight of the machine for proper compaction."