Road roller - Wikipedia
Road roller - Wikipedia
A road roller (sometimes called a roller-compactor, or just roller[1]) is a compactor-type engineering vehicle used to compact soil, gravel, concrete, or asphalt in the construction of roads and foundations.[1] Similar rollers are used also at landfills or in agriculture.
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Road rollers are frequently referred to as steamrollers, regardless of their method of propulsion.[2]
History
[edit] Main article: SteamrollerThe first road rollers were horse-drawn, and were probably borrowed farm implements (see Roller).
Since the effectiveness of a roller depends to a large extent on its weight,[3] self-powered vehicles replaced horse-drawn rollers from the mid-19th century. The first such vehicles were steam rollers. Single-cylinder steam rollers were generally used for base compaction and run with high engine revs with low gearing 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 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 were often dedicated to a task by their gearing as the slower engines were for base compaction whereas the higher geared models were often referred to as "chip chasers" which followed the hot tar and chip laying machines. Some road companies in the US used steamrollers through the s. In the UK some remained in service until the early s.
As internal combustion engines 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 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 disliked 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 use today use diesel power.
Uses on a road
[edit]Road rollers use the weight of the vehicle to compress the surface being rolled (static) or use mechanical advantage (vibrating). Initial compaction of the substrate on a road project is done using a padfoot or "sheep's foot" drum roller, which achieves higher compaction density due to the pads having less surface area. On large freeways, a four-wheel compactor with padfoot drum and a blade, such as a Caterpillar 815/825 series machine, would be used due to its high weight, speed, and the powerful pushing force to spread bulk material. On regional roads, a smaller single padfoot drum machine may be used.
The next machine is usually a single smooth drum compactor that compacts the high spots down until the soil is smooth. This is usually done in combination with a motor grader to obtain a level surface. Sometimes at this stage a pneumatic tyre roller is used. These rollers feature two rows (front and back) of pneumatic tyres that overlap, and the flexibility of the tyres provides a kneading action that seals the surface and with some vertical movement of the wheels, enables the roller to operate effectively on uneven ground. Once the soil base is flat the pad drum compactor is no longer used on the road surface.[citation needed]
The next course (road base) is compacted using a smooth single drum, smooth tandem roller, or pneumatic tyre roller in combination with a grader and a water truck to achieve the desired flat surface with the correct moisture content for optimum compaction. Once the road base is compacted, the smooth single drum compactor is no longer used on the road surface (there is an exception if the single drum has special flat-wide-base tyres on the machine).
The final wear course of asphalt concrete (known as asphalt or blacktop in North America, or macadam in England[citation needed]) is laid using a paver and compacted using a tandem smooth drum roller, a three-point roller or a pneumatic tyre roller. Three point rollers on asphalt were once common and are still used, but tandem vibrating rollers are the usual choice now. The pneumatic tyre roller's kneading action is the final roller to seal the surface.
Rollers are also used in landfill compaction. Such compactors typically have padfoot drums, and do not achieve a smooth surface. The pads aid in compression, due to the smaller area contacting the ground.
Configurations
[edit]The roller can be a simple drum with a handle that is operated by one person and weighs 45 kilograms (100 lb) or as large as a ride-on road roller weighing 20 tonnes (20 long tons; 22 short tons) and costing more than US$150,000. A landfill unit may weigh 54 tonnes (53 long tons; 60 short tons).
Roller types
[edit]Pedestrian-operated
[edit]- 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
[edit]- Tandem drum (static)
- Tandem drum (vibrating)
- Single drum roller (smooth)
- Pneumatic-tyred Roller, called rubber tyre or multi-wheel
- Combination roller (single row of tyres and a steel drum)
- Three point roller (steam rollers are usually three-point)
Ride-on soil/landfill compactor with pads/feet/spikes
[edit]- Single drum roller (soil)
- 4-wheel (soil/landfill)
- 3-point (soil/landfill)
- Tandem drum (soil/landfill)
Other
[edit]- Tractor-mounted and tractor-powered (conversion – see gallery picture below)
- Drawn rollers or towed rollers (once common, now rare)
- 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
[edit]Drums are available in widths ranging from 610 to 2,130 millimetres (24 to 84 in).
Tyre roller types
[edit]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
[edit]- On some machines, the drums may be 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 be ballasted with water or sand, or for extra compaction wet sand is used. Modern tyre rollers may be filled with steel ballast, which gives a more even balance for better compaction.
- Additional compaction may be achieved by vibrating the roller drums, allowing a small, light machine to perform as well as a much heavier one. Vibration is 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 be rotated relative to the main weight, to adjust the vibration amplitude and thus the compacting force.
- Water lubrication may be 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 be 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.
Gallery
[edit]- Powered, vibrating walk-behind
- Ride-on with articulating-swivel (small machine)
- Ride-on with articulating-swivel (large machine)
- Ride-on with articulating-swivel, Bomag BW 219 DH WR
- Vibrating Dynapac CC232
- A Caterpillar CS-533E vibratory roller.
- Pneumatic roller
- A road-roller powered by a tractor mounted on it
Manufacturers
[edit]- ABG (Germany) — SD/TD (purchased by Ingersoll Rand and now part of Volvo CE)
- Albaret (France) — PT/TD (now part of Caterpillar)
- Ammann Group (Switzerland) —
- Aveling-Barford (England) — TD/PT/3P
- BOMAG (Germany) — SD/TD/PT (BOMAG/HYPAC in the US market)
- Case CE (US) — SD (brands the Ammann/Sta machines as Case in the US)
- Caterpillar Inc. (US) — SD/TD/PT (has the former lines of RAYGO, BROS and Bitelli)
- Dynapac (Sweden) — SD/TD/PT/3P
- Galion (US) —
- Hamm AG (Germany) — SD/TD/PT/3P (now part of the Wirtgen Group)
- HEPCO (Iran) — SD/TD/PT/3P
- Hitachi (Japan) — SD/TD/PT/3P
- Huber Company, (US) —
- Hyster (US) — SD/TD/PT (part of HYPAC and Bomag USA)
- Ingersoll Rand (US) — SD/TD/PT (now owned by Volvo)
- Kamani Engineering Corporation (India) — tractor-mounted (now part of the RPG Group; production ended c. –)
- LiuGong, HQ at Liuzhou, China —
- Marshall (England) — TD
- Sakai Heavy Industries (Japan) — SD/TD/PT/3P
- Sany (China) — SD/TD/PT
- World Equipment(China) — SD/TD/PT
- Tampo (US) — SD/TD
- Vibromax (Germany) — SD/TD/PT (purchased by JCB, now branded JCB)
- Wacker Neuson (Germany) —
KEY:
- SD = Single drum
- TD = Tandem drum
- PT = Pneumatic tyre — Rubber tyre or multi-tyre are also common
- 3P = 3-point rollers — These are very similar to the old steam roller design
See also
[edit]- Tractor
- Roller (agricultural tool) – for farm rollers
- Roller (disambiguation) – for other types of roller
- Landfill compaction vehicle
- Mine roller – a demining device
References
[edit]Road Rollers: Everything You Need to Know - HBXG
Road rollers are essential machines in the construction industry, primarily used for compacting soil, gravel, concrete, and asphalt during the creation of roads and other structures. Understanding the types, uses, and benefits of road rollers can help you choose the right one for your project. In this article, we will cover everything you need to know about road rollers, including their different types, working principles, and common applications.
What Are Road Rollers?
Road rollers, also known as compaction rollers or simply rollers, are heavy machinery designed to compact different types of surfaces. These machines use a combination of static pressure, vibration, and impact to reduce the air pockets in the material, resulting in a dense, flat surface. They play a crucial role in road construction, ensuring that the surface is smooth and compact, which improves the lifespan and durability of roads.
Road Roller
Types of Road Rollers
There are several types of road rollers, each designed for specific tasks and materials. The main types include:
1. Smooth-Wheeled Rollers: These rollers have a smooth drum surface and are ideal for compacting asphalt layers and other granular materials. They can be static or vibratory, depending on the job requirements.
2. Pneumatic-Tired Rollers: These rollers have multiple rubber tires and are used for compacting materials like soil, asphalt, and granular layers. They provide a more uniform compaction due to the kneading effect of the tires.
3. Sheepsfoot Rollers: This type features a drum with a series of projections (sheepsfoot) that compact the soil by kneading it. They are ideal for compacting cohesive soils like clay and silt.
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4. Vibratory Rollers: These rollers use vibratory force along with static weight to achieve better compaction. They are suitable for compacting non-cohesive materials like sand and gravel.
How Do Road Rollers Work?
The operation of road rollers is relatively straightforward. The machine moves across the surface that needs compaction, applying pressure through its heavy drum or tires. Depending on the type of roller, vibration or kneading action is also applied, which helps reduce air pockets and increase the density of the material. This results in a more stable and durable surface that is essential for road construction.
Some road rollers are equipped with vibratory mechanisms that increase the impact force, improving the compaction process. In general, multiple passes are required to achieve the desired level of compaction.
Applications of Road Rollers
Road rollers are used in a variety of applications, primarily related to construction and infrastructure development. Some of the most common uses include:
1. Road Construction: Road rollers are critical in the construction of highways, streets, and parking lots. They are used to compact the base layers of gravel and asphalt to create a smooth, durable surface.
2. Landfill Compaction: Road rollers are used in landfills to compact the waste materials, helping to conserve space and prevent the formation of voids in the landfill.
3. Railway Construction: In railway construction, rollers are used to compact the ballast and other materials used to support the tracks.
4. Landscaping Projects: Rollers are also employed in landscaping to compact soil and other materials, providing a stable foundation for plants or other structures.
Benefits of Using Road Rollers
Using road rollers offers several advantages, including:
1. Improved Surface Stability: Road rollers create a stable and smooth surface by reducing air pockets and increasing material density, which extends the life of roads and other infrastructure.
2. Increased Durability: Properly compacted surfaces are less prone to cracking, settling, or erosion, making them more durable and cost-effective in the long run.
3. Enhanced Load-Bearing Capacity: Compacted surfaces can support heavier loads without shifting or sinking, making them ideal for roads, highways, and other high-traffic areas.
4. Efficient Construction: Road rollers allow for faster and more efficient compaction, helping to speed up construction timelines and reduce labor costs.
Questions and Answers About Road Rollers
Q: What type of road roller is best for asphalt compaction?
A: Smooth-wheeled rollers, particularly vibratory rollers, are ideal for compacting asphalt layers. They provide a smooth finish and uniform compaction for road surfaces.
Q: Can road rollers be used for compacting soil?
A: Yes, road rollers are commonly used to compact soil, especially in construction projects that require stable foundations. Sheepsfoot rollers are particularly effective for compacting cohesive soils like clay.
Q: How do vibratory rollers differ from static rollers?
A: Vibratory rollers use vibration along with static weight to achieve better compaction, making them more effective for non-cohesive materials like sand and gravel. Static rollers rely solely on their weight for compaction.
Q: How many passes are required for effective compaction?
A: The number of passes depends on the type of material being compacted, the roller type, and the project requirements. In general, multiple passes are needed to achieve optimal compaction levels.