Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/165927
rentsmart | by Marcia Gruver Doyle MGruver@randallreilly.com Be prepared to answer these 7 questions when renting a ride-on compactor BOMAG's Economizer (inset) is on-board tool that gives operator feedback on the stiffness of material being compacted, giving alerts on over compaction and/or soft spots. What type of material will you be compacting? If you're compacting soil, know what type of soil – gravel, sand, silt or clay. Gravel and sandy soils call for a smooth drum vibratory roller; if you're dealing with silt or clay materials, investigate a sheepsfoot (also called a padfoot) roller. Since sandier soils are granular and easier to compact, you'll be able to compact thicker lifts than you would with a silt or clay soil, says Mike Watt, Volvo Construction Equipment. Another factor is the moisture content of the soil that will be compacted, since drier soils are harder to compact. The type of soil also has a role in the amount of centrifugal force that needs to be applied, Watt says. Sandy soils require around 1,900 vibrations per minute, while clay requires around 1,300 vpm. Volvo, for example, offers up to five different frequencies on some compactors to match differing conditions. 1 Whether you're compacting soil or asphalt, your rental dealer has a machine designed for your job. To narrow the options down, however, expect to answer these questions when renting a ride-on compactor. If you're compacting asphalt, keep in mind the required density factor, Watt says. "Mixes have changed so much, and the type of stone is in the mix will affect whether you want to go with a pneumatic (or rubber-tired) roller, a smooth drum with the vibration on, or a smooth drum with the vibration off." How thick will the lifts be? Lift thickness is a key job spec to know, says David Dennison, BOMAG. "The thicker the lift, the more vibratory force and weight required," he says. "While you can do multiple lifts of thinner layers, if you're in a production situation, a thinner lift is not always an option." Machine weight is important to consider in relation to the size of the lift and the final compaction density, according to Katie Pullen, Case Construction Equipment. "A heavier machine used on a thinner lift can cause over-compaction," she says, "while a lighter machine on too thick of a lift can leave the base of the lift improperly compacted." 2 EquipmentWorld.com | September 2013 43 EW0913_Rentsmart.indd 43 8/27/13 3:32 PM