Brief introduction of roller
Also known as compactor. Road rollers belong to the category of road equipment in construction machinery. They are widely used in filling compaction operations of high-grade highways, railways, airport runways, dams, stadiums, and other large engineering projects. They can roll sandy, semi-cohesive and cohesive soils; Subgrade stabilized soil, and asphalt concrete pavement layer.
- According to the scope of work quality
According to different work quality, rollers can be divided into light, small, medium, heavy and super-heavy
- According to the principle of compaction
According to different compaction principles, rollers can be divided into static action type, vibration type, and impact type
- According to the structure and function of the compaction wheel
(1) According to the compaction wheel structure type, the road roller can be divided into smooth wheel type, bump (sheep foot roller) type, and tire type.
(2) According to the compaction wheel combination type, the roller can be divided into tire-smooth wheel combination type, vibration-oscillation combination type, etc.
(3) According to the compaction wheel’s action form, vibratory rollers can be divided into vibratory, oscillating, and vertical vibrating types.
Road roller purchase
Choose according to project quality requirements:
- If you want to get a uniform compaction density, you can choose a tire roller. The tire roller does not destroy the soil’s original viscosity during compaction, and there is good bonding performance between the various layers of soil. The front-wheel can swing, so the reduction is more uniform, and there will be no false compaction.
- If you want to make the road surface compact and smooth, you can choose a full-drive roller.
In areas where the roller’s compaction capacity is not high, a flexible roller with lower line pressure can be used.
To achieve the compaction effect as soon as possible, a large tonnage roller can be used to shorten the construction period.
Choose according to layer thickness:
- When rolling asphalt concrete pavement, the roller’s weight, amplitude, and vibration frequency should be selected according to the paving thickness of the mixture. Generally, on thin pavements with a pavement thickness of less than 60mm, it is best to use a small 2-6t vibratory roller with an amplitude of 0.35~0.60mm to avoid piles, waves, and damage to aggregates;
- At the same time, to prevent the asphalt mixture from being too cold, it should be rolled immediately after paving. For thick plies with a thickness greater than 100mm, a large and medium vibratory roller with a high amplitude (up to 1.0mm) and 6~10t should be used.
Choose according to road type (grade):
- For the first and second national arterial roads and particular roads for automobiles, a sizeable vibratory roller with a high compaction capacity of 6~10t should be used; for roads below the third level, or when compaction operations are not frequently performed, it is best Equipped with a maneuverable and flexible vibratory roller of about 2t.
- For cement concrete roads, tire-driven tandem vibratory rollers can be used;
- For asphalt concrete pavement, a full-drive vibratory roller should be used;
- For the bottom layer of high-grade pavement roadbed, it is best to use tire rollers or tire-driven vibratory rollers for compaction to obtain uniform compactness;
- Statically acting smooth rollers can be used when repairing the road.
Choose according to the type of material to be pressed:
- For the compaction of rock fills, large-tonnage rollers should be used to displace large blocks;
- For the compaction of clay, it is best to use a bump tamping roller;
- For the compaction of the mixture, it is best to choose a vibrating roller to make the large and small particles mix evenly;
- Heavy-duty vibratory rollers should be used for slow-rolling for deep layer compaction, and static rollers should be used for shallow layers.
Roller rolling method
Operating rules for rollers
- During operation, the roller should start before it starts to vibrate. The internal combustion engine should be set to medium speed first and then adjusted to high speed.
- The engine should be stopped first when shifting and reversing, and the engine speed should be reduced when moving.
- It is strictly forbidden for the roller to vibrate on solid ground.
- When rolling a soft roadbed, you should first roll it 1-2 times without vibration, and then vibrate it.
- When rolling, the vibration frequency should be consistent. For a vibratory roller that can adjust your vibration frequency, you should first adjust the vibration frequency before working. Do not change the vibration frequency without starting vibration.
- The reversing clutch’s adjustment, shock clutch, and brake should be carried out after the primary clutch is disengaged.
- When going up or downhill, fast gears are not allowed. In sharp turns, including articulated vibratory rollers when rolling in small turns, short loads are strictly prohibited.
- The roller shall not engage with vibration when it is running at high speed.
- When stopping, stop the vibration first, then put the reversing mechanism in the middle position, put the transmission in neutral, and finally pull up the hand brake lever. The internal combustion engine will turn off after idling fo
Roller rolling skills
①Whether it is uphill or downhill, the bottom layer of the asphalt mixture must be clean and dry, and the asphalt bonding layer must be sprayed to prevent the medicine from slipping during rolling.
②Whether it is rolling uphill or rolling downhill, the driving wheel of the roller should be behind. This has the following advantages: When going uphill, the rear driving wheels can withstand the driving force provided by the ramp and the machine itself, while the front wheels initially compact the road surface to withstand the greater shearing force generated by the driving wheels; When going downhill, the impact force generated by the roller’s weight is offset by the braking of the driving wheel, and only the mixture after being rolled by the front wheel can support the shearing force of the rear driving wheel.
③When rolling uphill, the roller should start, stop and accelerate smoothly to avoid excessively high or low speed.
④Before uphill rolling, the mixture should be cooled to the specified lower limit temperature, and then statically pre-compressed. When the mixture’s temperature drops to the lower limit (120°C), vibration compaction is used.
⑤When rolling downhill, avoid sudden shifting and braking.
⑥When rolling down a slope with a very steep slope, a light roller should be used for pre-compression, and then a heavy roller or vibratory roller should be used for compaction.