What are the latest technology trends in compaction equipment?
The oscillation technology developed by Hamm is innovative technology which allows the Hamm oscillation rollers to adjust to changed soil conditions almost immediately. The oscillation rollers are true high performance machines. They compact with low impact, thereby preventing damage to the environment and to adjacent buildings. In addition, fewer passes are needed than with rollers with vibration technology. Furthermore, when oscillation is used, the compaction continuously increases and hence the structure of the material does not loosen up. Another advantage of oscillation is the excellent surface finish of the compacted surface.

During the oscillation compaction, both the forward and the backward rotating movements of the roller drum transmit shearing forces in to the soil and asphalt. This double frequency causes the material to compact more quickly. On the other hand, the vibration drum executes an up-and-down movement and each time the imbalance weight rotates, it transmits forces in to the material just once. When the oscillation is used, the high compaction rate is also increased by the effect of the roller's own weight (static linear load) one hundred per cent of the time. Hamm has developed an imbalance system that combines both dynamic systems in one roller drum. VIO drums can vibrate like a vibratory or an oscillating drum, therefore they are ideally suited for compacting cohesive as well as non-cohesive soils. It is technically impossible to use both systems simultaneously. Oscillation is suitable for all layer types in asphalt construction, especially on thin asphalt courses or surfaces that are difficult to compact or are already well cooled down. Overall, the tandem oscillation rollers from Hamm have significant advantages over other compaction systems.

Could you tell us about the Wirtgen range of soil and asphalt rollers?
The Wirtgen range of soil and asphalt compactors are produced under the world class brand Hamm. Hamm soil compactors are best-in-class, using the fuel- efficient and highly durable Cummins engine. Hamm soil compactors are built with a patented design of a three- point pendulum articulated joint. The three-point articulation joint connects the front and rear ends of the compactor and enables excellent directional stability and steerability and provides driver safety on difficult terrain and for the driver's comfort.

Hamm asphalt compactors steer very gently and smoothly in order to prevent the asphalt from buckling and shifting. These compactors have excellent drum edge visibility with a sliding seat console and are able to compact very close to the curb. Operator safety and maintenance related features are inbuilt in the Hamm compactors which include safety indication and alarms for any faulty conditions.

What is the range on offer?
Wirtgen manufactures the Hamm brand of soil compactor of 11 T capacity and asphalt compactors of 9T capacities. In India, both the 11 T soil compactors and 9 T asphalt compactors are powered by 100 hp range engines.

How important is the role of an operator here?
The knowledge of the operator is very important when it comes to in selecting high amplitude/low frequency and low amplitude/high frequency modes in the compactor. As the compaction happens from bottom to top, the initial number of passes should be with high amplitude and when the compaction achieves a certain depth, then the remaining number of passes should be done with low amplitude. Change in the amplitude settings helps in optimising the fuel consumption and also to achieve better quality of compacted surface.