- Posted by The Rental Store
- On January 16, 2019
- Compaction, Machine Selection, Rammer Compactors, Vibratory Plate Compactors
Soil Type, Application Determine Choice of Rammer or Vibratory Plate
While rammers and plate compactors are both used for compaction, the machines are used for different applications and soil types. Know the job and soil type at the site to select compaction equipment that most efficiently completes your project.
Soils are commonly mixtures of clay and granular materials, so choose the machine that operates most effectively for the larger percentage of the mixture. On-the-job equipment testing may be required to achieve the best machine-to-job match.
The application also must be considered. The operator needs compaction equipment that is large enough for the job, yet easy to use. Ease of use includes not only handling, but fuel options, and the availability of fuel at the jobsite.
Rammers deliver a high impact force (high amplitude) making them an excellent choice to compact cohesive and semi-cohesive soils. A superb method for attaining maximum density on most cohesive soil, rammers’ frequency ranges are typically 500 to 750 blows per minute. Rammers derive compaction force from a small gasoline or diesel engine powering a large piston set with two sets of springs. The rammer is inclined at a forward angle to allow forward travel as the machine jumps.
Modern rammers are designed to provide high impact forces while being lightweight, enabling operators to maneuver them into various jobsite applications.
Making the Right Choice
Vibratory plates are low amplitude and high frequency, designed to compact granular soils and asphalt. Asphalt is considered granular due to its base of mixed aggregate sizes (crushed stone, gravel, sand and fines) mixed with bitumen binder (asphalt cement).
In vibratory plates, gasoline or diesel engines drive one or two eccentric weights at a high speed to develop compaction force. The resulting vibrations cause forward motion. The heavier the plate, the more compaction force it generates. Frequency ranges are usually 2,500 to 6,000 vpm.
Reversible plates have two eccentric weights that allow smooth transition for forward or reverse travel, plus increased compaction force as the result of dual weights. Due to their weight and force, reversible plates are ideal for semi-cohesive soils. Unlike standard plates, the reversible’s forward travel may be stopped and the machine will maintain its force for “spot” compaction.
Additional information on compaction equipment and the proper application can be found at Petersonrents.com.