Japan Used Road Roller Machinery: A road roller is a compactor type of engineering vehicle used to compact soil, gravel ,concrete soil, gravel ,concrete, or asphalt in the construction of roads and foundations. Roller can be either self-propelled or drawn, in their operating earth, road foundations, and road surfaces by rolling.
The working parts of a road roller are rigid steel drums. The surfaces of the drums can be flat or with a grid or cams (lugs). The rigid drumsincertain designs have replaced by pneumatic tires. Tractor drawn rollers with flat drums (static and vibration action), cams, and balloon-tired rollers used to compact earth and road foundations. The self-propelled rollers with flat drums(two-drum or three-drum, static or vibration action) and with balloon tires used chiefly for compacting road surfaces of compacting depends on the specific pressure on the surface the weight of the roller increased by using ballast (reinforced-concrete blocks or containers with sand). The weight of a road roller is from 5 to 50 tons, and it operates at a speed of 2-8 km/hr.
The first road rollers horse- drawn, and probably just borrowed farm implements. The effectiveness of a roller depends to a large extent on its weight, self -powered vehicles replaced horse-drawn rollers from the mid-19th century. The first vehicle were steam rollers. Single-cylinder steam rollers generally used for base compaction and run with high engine revs in a low gear to promote bounce and vibration from the crankshaft through to the rolls in much the same way as a vibrating roller.
The double cylinder or compound steam rollers became popular from around 1910 onwards and were used mainly for the rolling of hot-laid surfaces due to their smoother running engines, but both cylinder types are capable of rolling the finished surface. Steam rollers often dedicated to a task by their gearing as the slower engines for base compaction whereas the higher geared models often referred to as ‘chip chasers’ which followed behind the hot tar and chipping laying machines. Some road companies in the United States used steamrollers through the 1950s, and in the UK, some remained in commercial service until the early 1970s.
As internal combustion engine technology improved during the 20th century, kerosene, gasoline- (petrol), and diesel-powered rollers gradually replaced their steam-powered counterparts. The first internal-combustion powered road rollers were very similar to the steam rollers they replaced. They used similar mechanisms to transmit power from the engine to the wheels, typically large, exposed spur gears. Some users did not like them in their infancy, as the engines of the era were typically difficult to start, particularly the kerosene-powered ones. Virtually all road rollers in commercial use now use diesel power.
Roller working principle is based on vibration, impact loading, kneading and by applying direct pressure on the respective layer.
The four most commonly used rollers are:
Vibratory type rollers have two smooth wheels/drums plus the vibrators. One is fixed at the front and the other one is on the rear side of vibratory roller. Both wheels/drums are of the same diameter, length and also of same weight. Vibratory roller covers the full area under wheel. To make vibratory roller more efficient, vibrators are also fixed with smooth wheel rollers. Vibration of vibrators arrange the particles by first disturbing even the arranged ones. On the other hand weight of wheels exerts direct pressure on the layer.
Vibrators are turned off during the reversed motion of roller. In that time only static weight directly acts on the soil layer. Vibration is to reduce the air voids and to cause densification of granular soils. During vibration of soil layer, rearrangement of particles occurs due to deformation of the granular soil because of oscillation of the roller in a cycle. Tamping roller/sheep foot roller: Sheep foot roller also named tamping roller. Front steel drum of sheep foot roller consists of many rectangular shaped boots of equal sizes fixed in a hexagonal pattern.
Coverage area of sheep foot roller is less i.e., about 8- 12% because of the boots on drums. Sheep foot roller done compaction by static weight and kneading of respective layer. This makes tamping roller better suited for clay soils. Contact pressure of sheep foot roller varies from 1200- 7000 Kpa. Tamping foot roller consists of four wheels and on each wheel kneading boots/feet are fixed. Tamping roller has more coverage area i.e., about 40- 50%. Contact pressure of tamping roller varies from 1400 – 8500 KPa. It is best dedicated for fine grained soils.
Smooth Wheel Rollers:
Smooth wheel roller and vibratory rollers are the same. Both have the same characteristics. Only the difference in both is vibratory equipment. Smooth wheel roller has no vibrator attached with the drum. This makes smooth wheel roller best suited for rolling of weaker aggregates, proof rolling of subgrades and in compacting asphalt pavements. Compaction of clay or sand is not a good choice to done with smooth wheel roller. This is so, because there are many empty voids in clay soil and sand, which cannot be minimized without vibrators.
Pneumatic Tired Roller:
Japan Used Road Roller Machinery: Pneumatic tired roller has a number of rubber tires at the front and at the rear end. So, empty spaces left in between the two tires that make 80% coverage area under the wheels. Pneumatic roller has the ability to exert contact pressure ranges from 500 – 700 Kpa. Pneumatic tired roller can be used for highways, construction of dams and for both fine grained and non-cohesive soils. It is also used for smoothening of finishing bitumen layer on highways, roads, streets etc.
- Rammer (bounce up and down).
- Walk-behind plate compactor/light.
- Trench roller (manual unit or radio-frequency remote control).
- Walk-behind roller/light (single drum).
- Walk-behind roller/heavy (double drum).
Ride-on Smooth Finish
- Tandem drum (static).
- Caterpillar Inc.
- Tandem drum (vibrating).
- Galion Iron Works
- Single Drum Roller (Smooth).
- LiuGong Construction Machinery, LLC
- Pneumatic-tyred Roller, a.k.a. rubber tyre or multi-wheel.
- New Holland Machine Company
- Combination roller (single row of tyres and a steel drum).
Ride-on soil/landfill compactor with pads/feet/spikes
- Single drum roller (soil).
- 4-wheel (soil/landfill).
- 3-point (soil/landfill).
- Tandem drum (soil/landfill).
- Tractor-mounted and tractor-powered.
- Drawn rollers or towed rollers (were very common once, but not so now).
- Impact compactor (uses a square or polygon drum to strike the ground hard for proof rolling or deep lift compacting).
- Drum roller with rubber coated drum for asphalt compaction.
- Log skidder converted to compactor for landfill.
- Wheel loader converted to compactor for landfill.
Drum Types: Drums are available in widths ranging from 24 to 84 inches (0.6 to 2 metres).
Tyre Roller Types:
Japan Used Road Roller Machinery: Tyre rollers are available in widths ranging up to 2.7 metres (8.9 ft), with between 7 and 11 wheels (e.g. 3 wheels at front, 4 at back): 7 and 8 wheel types are normally used in Europe and Africa; 9 and 11 in America; and any type in Asia. Very heavy tyre rollers are used to compact soil.
Variations and Features:
- On some machines, the drums may filled with water on site to achieve the desired weight. When empty, the lighter machine is easier and cheaper to transport between work sites. On pneumatic tyre rollers the body may ballasted with water or sand, or for extra compaction wet sand used. Modern tyre rollers may be filled with steel ballast, which gives a more even balance for better compaction.
- Additional compaction may achieved by vibrating the roller drums, allowing a small, light machine to perform as well as a much heavier one. Vibration typically produced by a free-spinning hydrostatic motor inside the drum to whose shaft an eccentric weight has been attached. Some rollers have a second weight that can rotated relative to the main weight, to adjust the vibration amplitude and thus the compacting force.
- Water lubrication may provided to the drum surface from on-board “sprinkler tanks” to prevent hot asphalt sticking to the drum.
- Hydraulic transmissions permit greater design flexibility. While early examples used direct mechanical drives, hydraulics reduce the number of moving parts exposed to contamination and allows the drum to driven, providing extra traction on inclines.
- Human-propelled rollers may only have a single roller drum.
- Self-propelled rollers may have two drums, mounted one in front of the other (format known as “duplex”), or three rolls, or just one, with the back rollers replaced with treaded pneumatic tyres for increased traction.
Road Roller Manufacturers:
- ABG (Germany)
- Albaret (Francer)
- Ammann Group (Switzerland)
- Aveling-Barford (England)
- BOMAG (Germany)
- Case CE (USA)
- Caterpillar Inc.
- Galion (USA)
- Huber Company