"You see the popularity of larger plates with remote controls in some pockets of the States," says Price. "You'll see it in some southern states, parts of California and Alaska and in some areas in Canada. It's mainly in regions where there are a lot of cave-ins."
When it comes to selecting which types of compaction equipment you should have in your rental inventory, it's all about knowing your market and the types of soils your customers will be dealing with, say sources.
"Who are your customers? What are they going to be doing? What type of soil is in your area? These are the questions you need to ask," says Benedict with Ingersoll-Rand. "Contractors want to rent the most productive machine they can without spending a lot. Most likely, they'll know what they need. So you're best bet is to talk to the contractors and find out what you need to have in inventory to best meet their needs."
Vibratory compaction: The science behind it
You might have various types of light vibratory compaction equipment in your rental inventory. But do you know what this equipment is actually doing? Here from Compaction and Paving, Theory and Practice from Dynapac, is a glimpse at what is happening.
Vibratory compaction equipment makes use of a vibrating mechanism, which normally consists of a rotating eccentric weight.
Vibratory compactors use a combination of dynamic and static loads. They deliver a rapid succession of impacts to the underlying surface from where the vibrations, or pressure waves, are transmitted through the material to set the particles in motion. This virtually eliminates the internal friction, and facilitates the rearrangement of the particles into positions that result in as low a void space and as high a density as possible. The increase in the number of contact points between the particles leads to high stability and strength.
Owing to the cohesive forces between particles in most soils, the vibratory force must be combined with loads of a certain magnitude to overcome the cohesion. On sand and gravel, which have a low apparent cohesion, comparatively light loads are sufficient. This means that light rollers and plate compactors can be used with good effect.
Clay and other cohesive materials require heavier loads and therefore require the use of comparatively heavy compaction equipment. However, these types of material can only be compacted in relatively thin layers.
Initially vibratory compaction was only considered suitable for rock fill, sand and gravel, but as vibratory techniques developed, the method has come to be used for clay soils and successively for asphalt compaction, too.