5 Reasons Large Drums Are Preferred on Tandem Asphalt Rollers

That’s why we engineer our tandem rollers with large drum diameters. Other OEMs sometimes use smaller drums, whether to lower production costs, or for marginal gains in fuel economy, maneuverability or higher frequencies. Here at Volvo, though, we believe the overall gains in jobsite efficiency and mat quality with a larger drum are key. As a result, over the years we've become known for delivering superior drum performance and exceptional mat smoothness.

Large drum diameters on asphalt compactors are often preferred over smaller drum diameters for several reasons, which can translate into significant advantages during the compaction process. Here’s what I consider the top five advantages of larger drums:

1. Increased Contact Area and Reduced Mat Distortion

• Advantage: A larger drum diameter increases the contact area, or arc length, between the drum and the hot asphalt mix. This larger footprint distributes the roller’s weight and compaction force over a greater surface area.
• Benefit: This wider contact area minimizes distortion, pushing or shoving of the fresh asphalt mat, especially during the initial passes when the mix is most pliable. It helps prevent the formation of “bow waves” in front of the drum, leading to a smoother, more uniform surface.

2. Smoother Ride and Finish

• Advantage: The larger radius of a big drum helps your asphalt compactor “bridge” over minor irregularities in the mat more effectively.
• Benefit: This results in a smoother finish on the compacted asphalt, reducing the likelihood of bumps or inconsistencies that can affect the pavement’s ride quality and longevity (and potentially your bonus).

3. Fewer Impacts Per Foot (for Vibratory Rollers)

• Advantage: With a larger drum diameter, fewer impacts per foot are needed to achieve the desired compaction.
• Benefit: This allows the roller to maintain proper impact spacing even at higher travel speeds, improving efficiency and production rates without sacrificing compaction quality. It also minimizes excessive wear on your machine.

4. Better Compaction Depth and Efficiency

• Advantage: While static pressure can be higher with narrower drums (due to weight being distributed over a smaller area), larger drums, especially in vibratory mode, can deliver more effective impact energy to compact deeper into the asphalt lift.
• Benefit: This leads to more efficient compaction in fewer passes, achieving target densities faster and reducing overall project time.

5. Reduced Drum Edge Markings

• Advantage: The larger, smoother surface of a wide-diameter drum tends to leave fewer noticeable drum edge marks or indentations on the asphalt.
• Benefit: This contributes to a cleaner, more aesthetically pleasing finished surface.

In essence, larger drum diameters contribute to a more efficient, higher-quality compaction process, resulting in a smoother, more durable and better-performing asphalt pavement. Larger drum diameters on asphalt rollers are worth it because they can help you hit more targets more often.

So why wouldn’t we develop a significantly larger diameter drum, like a 10-foot diameter drum for a DD120C? Well, for one that would look ridiculous — it would also pose several mounting problems. If you start adding weight, you need to balance maneuverability for the machine design because you’ll start to lose maneuverability as your diameter increases. The machine fuel efficiency can also be impacted due to the greater surface contact area.

At Volvo, we’ve taken the time to study and analyze these factors and provide the optimum drum diameter per the drum width and machine characteristics to ensure that you experience outstanding compaction performance and mat smoothness.

Be sure to check out these additional Volvo compactor advantages and reach out to your local Volvo dealer if you’d like to learn more. 

Justin Zupanc
Product Manager – Compaction

Justin started with Ingersoll-Rand in 2003 and has continued his career with Volvo Construction Equipment as an electrical engineer working in various roles from design and systems engineering to cab engineering manager and more.