Over 30 years ago, HAMM became the first roller manufacturer to offer an oscillation drum for tandem rollers, and these rollers have become an integral part of its product offering. In the past five years alone, the specialists for compaction technology have delivered more than 3,000 machines with this innovative technology. Today, one in four of the tandem rollers made by HAMM is equipped with an oscillation drum. With more than 30 models to choose from, HAMM has by far the widest offering of oscillation rollers in the world. And only HAMM builds oscillation tandem rollers in the compact class, as well as soil compactors with oscillation compaction capability.
Fast, cost-effective and high-quality
The reason for this success is simple: oscillation rollers make for fast, cost-effective and high-quality dynamic compaction. In particular, tandem rollers with one oscillation drum and one vibrating drum achieve at least the same degree of compaction as double vibrating drum rollers, but with fewer passes. Another benefit is the extremely low vibration provided by oscillation, making dynamic compaction on bridge overlays, of thin layers, and in sensitive areas — such as near hospitals, city centers, rail tracks, or industrial plants — possible for the first time. The scope of applications is enormous.
Compaction at every construction phase
Another bonus is that oscillation rollers can start dynamic compaction directly behind the paver (→ breakdown phase). They can then also deal with the main compaction (→ intermediate phase). And even with lower asphalt temperatures at the end of compaction (→ finish phase), oscillation ensures an increase in compaction without crushing the aggregate. Overall, when using oscillation rollers, the time available for compaction is significantly greater than with vibratory rollers.
Comprehensive portfolio for asphalt paving and earthwork
The HAMM portfolio encompasses tandem rollers for asphalt paving ranging from 2.5t to 15t. When it comes to the pivot-steered rollers in the DV+ series, a popular choice for demanding road building projects, the share of oscillation rollers is particularly high: in 2016, around 40 percent of all DV+ series rollers were delivered with oscillation drums.
The oscillation rollers for the compact class from 2.5 to 4.5t also experience great market demand. Hardly surprising, because HAMM is the world’s only manufacturer in this market segment. This also applies for earthwork. Customers worldwide seeking a solution for compactors with the facility to choose between oscillation and vibration find that only HAMM has the answer in the form of its VIO drums.
Maximum wear resistance
HAMM’s experience of more than 30 years is also reflected in the way in which oscillation technology is incorporated in the design. An example of this is the drum shell. On oscillation drums, it is inevitably subject to greater stresses, due to the constant ground contact, than is the case with vibrating drums.
The operating life of HAMM oscillation drums is similar to that of vibrating drums, made possible by using highly wear-resistant fine grain steel for the drum shell, its thickness is more than 150% greater than that of comparable competitors’ machines.
In addition, an integral reinforcing ring ensures that the drum is extremely hard-wearing. This is why HAMM confidently provides a remarkable warranty against wear of at least 4 000 operating hours.
Low-maintenance operation
HAMM’s oscillation drums are designed to require very little maintenance. The toothed belt, the core element of the drive, has been perfectly attuned to the overall system: its operating life corresponds to that of the entire drum. Checking the belt tension after 2 000 operating hours is all that is recommended.
Use for all layers
Oscillation rollers can be used to compact all earthwork and road building layers. They come into their own in earthwork, where re-loosening of the upper layers has to be effectively prevented, such as in garden and landscaping work. Another important application is the compaction of soils in vibration-sensitive areas, for example above gas, water and other pipework.
In asphalt paving, base courses, binder courses and surface courses can be reliably compacted with oscillation rollers. They perform especially well in the compaction of generally hard-to-compact asphalts such as SMA or in the case of polymer-modified material mixes. This is because, in contrast to vibration compaction, the effective direction of the vibrations during oscillation promotes the desired redistribution of long-chain binding agents.
Other applications include work on thin layers (surface courses, thin overlays), in vibration-sensitive areas (bridges, confined urban spaces, buildings or parking decks) and wherever the mix cools quickly (thin layers, windy or cold environments). Also of particular importance is joint compaction where the hot asphalt is to be compacted without damaging the adjoining cold asphalt.
