Monobille ou bibille : comment le type de rouleau, la classe de poids et l'amplitude correspondent au compactage des sols et de l'asphalte, avec l'épaisseur de couche, la configuration des billes et le nombre de passes.
Buy a single-drum roller when the compaction target is soil, sub-base or embankment; buy a double-drum roller when the target is asphalt or any finished surface. The two machines use different drum designs for different materials, and a roller working the wrong material either fails the density test or marks the surface it was bought to finish.
What is the short answer?
Single-drum rollers put their weight on one smooth or padfoot drum with pneumatic tyres at the rear, which drives soil compaction; double-drum rollers put vibrating drums front and rear for even compaction across asphalt. If a project has both soil and asphalt, most contractors use a single-drum roller for the base and a double-drum for the wearing course.
| Decision factor | Single-drum roller | Double-drum roller |
|---|---|---|
| Drum layout | One vibratory drum plus rear tyres | Two vibratory drums, front and rear |
| Material | Soil, gravel, sub-base, embankment | Asphalt, surface courses, some granular base |
| Typical weight range | 1–20 t | 1–13 t |
| Compaction depth | 200–400 mm per lift, depending on weight | 50–100 mm per lift (asphalt layer depth) |
| Surface finish | Leaves a soil finish, cannot finish asphalt | Smooth finish, no tyre marks |
| Vibration control | Front drum only, easier near structures | Two drums; switch to static near bridges and joints |
| Typical new price band | USD 8,000–85,000 | USD 12,000–70,000 |
What is each type designed to do?
A single-drum roller is a soil machine: the driven drum kneads and vibrates the lift below it while the rear tyres compact the surface layer, which is why it is the standard tool for sub-base and embankment work. The combination of sheepsfoot or padfoot drum plus rubber tyres produces both deep and surface compaction in one pass.
A double-drum roller is a paving machine: two vibrating steel drums compact the asphalt mat from both directions, leaving no tyre marks and no shoving, which is why it is used on every asphalt job that will be inspected. Running asphalt with a single-drum roller fails the smoothness requirement even when the density is adequate.
How do you match roller weight to compaction depth?
As a working rule, each tonne of static roller weight compacts roughly 25 to 35 mm of granular lift, so a 3 tonne machine suits 75 to 100 mm lifts and a 10 tonne machine suits 250 to 350 mm lifts. Vibratory compaction extends that depth by 50 to 100 percent in granular material.
| Roller class | Suitable lift depth (granular) | Typical work |
|---|---|---|
| 0.5–1 t (walk-behind) | 50–100 mm | Trenches, kerbs, patching, footpaths |
| 1–3 t | 75–120 mm | Driveways, small car parks, granular base |
| 3–6 t | 150–220 mm | Road sub-base, estate roads, shoulders |
| 8–12 t | 250–350 mm | Main road sub-base, runway base, embankment |
| 13–20 t | 300–400 mm | Highways, dams, large earthworks |
Two corrections to that rule. Cohesive clay compacts far less per pass than granular fill, so halve the lift depth and increase the number of passes. And compaction falls off sharply with moisture outside the optimum range, so a roller that fails a density test is often a moisture problem rather than a weight problem. Our road roller range lists the classes available with drum configuration and amplitude figures.
Static, vibratory or pneumatic?
Vibratory rollers do most of the compaction work in granular material; static rollers finish and seal; pneumatic-tyred rollers compact asphalt and seal surfaces without crushing aggregate. Most modern single-drum machines are vibratory with switchable amplitude, which covers both modes on one machine.
| Mode | Best material | Use it when |
|---|---|---|
| Vibratory high amplitude | Thick granular lifts | Building sub-base away from structures |
| Vibratory low amplitude | Thin lifts, asphalt | Near kerbs, joints and buried services |
| Static | Asphalt finish, sensitive structures | Within 5 m of a bridge, wall or pipeline |
| Padfoot drum | Cohesive clay and silt | Clay fill where a smooth drum would polish the surface |
Which roller for asphalt, and which for soil?
For asphalt, use a double-drum roller with dual amplitude and a water spray system, and match the drum width to the paving width so you do not need overlap passes. For soil, use a single-drum roller with a padfoot or smooth drum and switchable amplitude, matched to the lift depth you intend to place.
On asphalt, three details matter more than brand. Drum width must cover the paver screed width in whole passes, the water spray must be adjustable to prevent pick-up without over-cooling the mat, and the drum must have dual amplitude so you can drop to low amplitude on thin lifts. On soil, the decisive detail is whether you can switch amplitude, because high amplitude on a thin lift loosens rather than compacts it.
What about small trenches, kerbs and repairs?
For trench and patch work, use a walk-behind single-drum roller or a remote-controlled trench roller, because a ride-on machine cannot enter a 300 to 600 mm trench safely. Walk-behind units from 0.5 to 1 tonne compact granular backfill in 50 to 100 mm lifts, which is the standard specification for utility reinstatement.
Remote-controlled trench rollers are worth the extra cost when the work is inside trenches deeper than 600 mm, since the operator stays outside the excavation. For asphalt patching, a walk-behind double-drum unit gives a finish that a plate compactor cannot match, and it is the difference between a patch that passes inspection and one that is rejected twice.
Frequently asked questions
Can a single-drum roller compact asphalt?
Only as a base course roller on thick lifts, and it will usually leave marks if used on the wearing course. Asphalt surfacing needs a double-drum roller with water spray and low-amplitude vibration, because surface finish is inspected as strictly as density.
How many passes does a roller need?
Typically four to six passes over the same lift, with overlap of about one third of the drum width, to reach 95 percent of maximum dry density in granular material. The number is confirmed by a field density test, not by counting, so run the test after the first panel.
What is the difference between amplitude and frequency?
Amplitude is how far the drum moves and controls the depth of compaction; frequency is how often it moves and controls the number of impacts per second. Thick lifts need high amplitude, thin lifts and asphalt need low amplitude with higher frequency.
Do I need a water tank on a soil roller?
Not for soil work, but a spray bar is useful when a smooth drum starts picking up wet clay. Rollers used mainly on clay benefit from a padfoot drum, which kneads and compacts rather than polishing the surface.
Next step
Envoyer us the material, the lift depth, the road or site width and whether the surface will be inspected, and we will recommend a drum configuration, weight class and amplitude setting. Browse the road roller range to compare classes, or read the complete sourcing guide for the loading, inspection and documentation side of the purchase.