The influence of improper use of pavers on the smoothness of road surfaces

(1) Adjust the traveling speed of the paver and the frequency of the rammer at will. The traveling speed of the paver should be adjusted based on the tonnage of the material discharged per unit time, the time it takes for a single dump truck to travel between the front and rear yards, the tonnage and quantity of the dump trucks, the thickness and width of the spread, and other factors. Never drive fast when there is a lot of material and slow when there is little. When adjusting the driving speed, the frequency of the rammer must be adjusted accordingly. If the driving speed is fast, the frequency of the rammer should be increased; conversely, it should be decreased. If only the driving speed is adjusted without adjusting the frequency of the rammer, it will cause inconsistent compaction before and after the adjustment. Although it looks very smooth, it will be uneven after compaction. Since the adjustment is made manually, it is impossible to make the compaction degree consistent before and after the adjustment. Moreover, when the driving speed is increased, the material is more likely to segregate. At the same time, the thickness (elevation) of the paving will also change. Therefore, the driving speed is generally better at around 3 meters per minute.

(2) The adjustment of the paving thickness (elevation) was too hasty. When setting a spreading thickness, the screed does not immediately reach the required height but rises slowly. Therefore, it is necessary to measure after the machine has passed at least three large arm lengths to accurately reflect the actual situation. Thus, it is strictly forbidden to measure right after the adjustment is completed. During construction, adjust the thickness difference gradually as much as possible, and all the adjustments are displayed on the control handle. The measurement should be made after the machine has traveled a certain distance. In road construction, since the base layer cannot be absolutely flat, there will definitely be some differences in the measured paving thickness, which cannot be adjusted at will by human factors.

(3) Random shutdown. Unsupervised dump trucks or improper command, or due to the paver traveling at too high a speed causing material interruption and other reasons, may all force the paver to stop. After the machine stops, when paving again, the screed will leave a mark on the road surface. Even if an anti-climbing lock is installed, there will still be a mark, but the screed will not climb. The clarity of the marks is related to the temperature of the material and the length of the downtime. If the material temperature is low and the downtime is long, the marks will be obvious, affecting the smoothness of the road surface. Therefore, during the normal paving process, it is necessary to ensure that the machine does not stop as much as possible.

(4) The tracks (tires) are slipping. Excessive braking of dump trucks, excessive spraying of emulsified asphalt on the base layer, excessive accumulation of materials in front of the screed, and severe wear of the track plates can all cause the tracks of the paver to slip. When the track slips, the machine's traveling speed has slowed down or even dropped to zero, while the frequency of the rammer remains unchanged. As a result, the compaction degree is inconsistent before and after the machine slips, affecting the smoothness of the road surface. Therefore, dump trucks must be under the command of a dedicated person, and too much emulsified asphalt should not be sprayed on the base layer. For a paver, the most important thing is not to pile up too much material in front of the screed. Generally, the height of the material piled up to two-thirds of the spiral blade is just right, and the spiral should rotate at a constant speed. The amount of material accumulation is related to the fixed height of the screw and the size of the material door. The fixed height of the screw should be adjusted according to the thickness of the spreading. Taking the ABG type machine as an example, when the spreading thickness is between 0 and 8cm, the height from the ground to the center of the screw should be 315cm (the minimum). When the paving thickness is between 4 and 15cm, the height from the ground to the center of the spiral should be 365cm (in the middle). When the paving thickness is over 15cm, the height from the ground to the center of the spiral should be 415cm (the maximum). Severe wear of the rubber blocks on the track plates not only causes the tracks to slip but also results in uneven contact with the ground. Although the paver is equipped with a leveling device, it still affects the smoothness of the road surface.

(5) The pre-selected elevation Angle was not adjusted properly. When laying a road surface with an uneven base and significant thickness differences, it is often encountered that the leveling cylinder has been adjusted to the extreme, but the thickness (elevation) still fails to meet the requirements, affecting the smoothness of the road surface. At this point, it is necessary to check whether the pre-selected elevation Angle of the paver is appropriate. The pre-selected elevation Angle should be adjusted according to the paving thickness. When the thickness is between 0 and 4cm, the elevation Angle can be less than 0. When the thickness is between 4 and 15cm, the elevation Angle should be 0. When the thickness is over 15cm, the elevation Angle should be greater than 0. When laying asphalt pavement, it is best for the scale of the leveling cylinder of the machine to be kept at 10 to 15 during normal operation. Some brands of pavers do not have direct visible scales. In this case, the overhang of the leveling cylinder can be adjusted as a reference.

(6) The sensitivity of the leveling instrument does not meet the requirements. If the sensitivity of the leveling instrument is too high, it is easy for the leveling cylinder to move up and down. If the sensitivity is too low, it will easily cause the leveling cylinder to respond slowly, directly affecting the smoothness of the road surface. It is generally appropriate to set the leveling instrument at around scale 5.

(7) The ironing plate is not in a floating position. During the paving operation, the screed should float on the material being paved. The thickness of the paving can be adjusted by changing the elevation Angle. If the screed is not in the floating position, the thickness of the paving cannot be adjusted.