Learn the rolling skills of road rollers, and you are an professional driver!

Road rollers belong to the category of road machinery and equipment in construction machinery, and are widely used in high-grade highways. The filling and compaction operations of railways, airport runways, dams, stadiums and other large-scale engineering projects can roll sandy, semi-cohesive and cohesive soils, roadbed stabilized soil and asphalt concrete pavement layers.

Principles of roller compaction

The compaction is carried out along the longitudinal direction of the line, and the principle of "first light and then heavy, first slow then fast, first edge and then middle (curve section is first inside and then outside)".

Use static pressure 1 pass + strong vibration 2-4 times + weak vibration 2 times + static pressure 1 pass, and the walking speed is controlled within 4km/h. The specific methods are as follows:

1. The compaction of the pavement should start from the edges on both sides of the road and gradually move to the center of the road. The two successive rolling belts must have a certain overlap width. The overlap width of the tandem roller and the single-wheel vibratory roller is 250～300mm, and the overlap width of the static three-wheel roller can be half of the main roller.

2. The best temperature for starting the first impact rolling is between 80-150℃ for petroleum pitch and 90-110℃ for residual oil pitch. If the rolling temperature is too high, the material will be squeezed in front of the roller, and it will expand along the edge of the roller to produce transverse cracks and stick to the roller. When the rolling temperature is too low, the viscosity of the asphalt becomes high and it is difficult to compact, and the road surface that has been rolled will crack.

3. The roller should be rolled as close as possible to the paver, and the method of applying light first and then heavy should be adopted to ensure that the compactness requirement is reached before the mixture is cooled to below the required minimum temperature.

4. When rolling the new asphalt mixture, the operator should first drive the driving wheel into the fresh mixture yard to reduce ripples and breakage.

5. Keep the vibration rolling speed constant, do not stop arbitrarily on the hot material surface; turn or start slowly, so as to minimize the indentation.

In the rolling process of the road roller, the low frequency is used first, and then the high frequency is used for the vibratory roller.

Because the amplitude of low frequency rolling is large, it is good for deep layer compaction; the amplitude of high frequency rolling is small, which is good for shallow layer compaction.

After the completion of rolling, the roadbed surface is leveled and a cross slope is made to ensure good drainage.

Roller rolling skills

1. During operation, the roller should start before it starts to vibrate, and the engine should be set to medium speed first, and then adjusted to high speed.

2. When rolling downhill under very steep slopes, light rollers should be used for pre-compaction first, and then heavy rollers or vibratory rollers should be used for compaction.

3. Whether 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 wheel can withstand the driving force provided by the ramp and the machine itself, while the front wheel performs preliminary compaction on the road surface to withstand the greater shearing force generated by the driving wheel; When going downhill, the impact force generated by the weight of the roller is offset by the braking of the driving wheel, and only the mixture after being rolled by the front wheel can support the rear driving wheel to generate shearing force.