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The first thing to do in most construction jobs is compaction. Therefore, creating a strong, sturdy base is essential for a successful construction project. For this purpose, perhaps the best tool for the job is a roller. The question arises here that which roller is right for your project? There are many different styles of rollers that work best for different kinds of compaction. The one that is most appropriate for any project can depend on the type of work that needs to be done or what kind or soil are we dealing with. Understanding of this and some other factors can help contractors decide which roller is best for them.
Sheepsfoot Roller
These rollers are unique owing to drum having many round/rectangular protrusions all over surface of the roller which are often called tamping roller. Sheepsfoot rollers are used mainly for compaction of cohesive, dense soils for example heavy or silty clays. However, they are not effective on loose or sandy soils due to the protrusions tilling the soil instead of compacting it. These rollers are called tamping rollers as well.
Various types of rollers can be acquired through machinery traders with different lengths and shapes of feet. The most common, however, is the one having two drums 1.22 meters wide and 1.06 as taper-foot or club-foot rollers because of the shape of the feet. The factors that determine the amount of compaction of soil include gross weight of the roller, no of lugs in contact with ground, area of every feet, total no of feet per drum etc. The soil should be consolidated when the impression by the projecting teeth is less than 12 mm deep or in case the surface has been rolled 16 to 20 times.
Vibratory Rollers
Vibratory rollers are equipped with smooth-surfaced steel wheels 0.9 m to 1.5 m in diameter and 1.2 m to 1.8 m wide. which send vibrations through the roller. These vibrations are generated by eccentric shaft rotating inside the wheel and hence make it an ideal roller for compacting granular base courses which would otherwise be difficult to compact. Self-propelled vibratory rollers are even available weighing from 4 to 6 tonnes. These vibrations are generated by rotation of a shaft inside. A vibratory roller is utilized for the purpose of compacting granular base courses.
Smooth-Wheeled Roller
Smooth-wheel rollers use one large, smooth steel drum in front and wheels on the rear end for compaction. These can be tandem, which are two wheel, or three-wheel rollers. Smooth wheel rollers are very good for gravel, sand, ballast, and surface dressings. However, this used construction equipment is not effective in compacting embankments or softer turf, but are the most effective in compacting sandy soils with the fewest passes.
Grid Rollers
Grid rollers have cylindrical heavy steel roller which consists of a network of steel bars coming together in order to form a grid-like pattern. This grid may also be ballasted with concrete blocks to accomplish additional contact pressure. These rollers are best for compacting most coarse-grained soils as they provide little kneading action along with high contact pressure. These rollers also consists of a heavy cylindrical steel surface made up of of multiple network of steel bars forming the grid with squire holes and can be ballasted with concrete blocks. They are usually towed units and can operate at speeds anywhere from 5 and 24 km/h. Typical weights can vary anywhere from 5 tonnes net to 15 tonnes ballasted. In addition, grid rollers also provide high contact pressure but with little kneading action and are suitable for compacting more of the most coarse grained soils.
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