Analysis of the Fault Causes of wavy road surfaces paved by asphalt pavers

An ABG525 asphalt paver found that the left side of the road surface was wavy while the right side was normal when laying asphalt pavement. Moreover, during the paving process, the screed and the already formed pavement are not in close contact, making it seem as if the screed is bouncing up and down. This phenomenon is particularly obvious at the corners or in areas where the roadbed is uneven. If the time for laying medium material is slightly longer, when starting again, the left side of the paved road surface will be obviously raised, while the right side will be normal.

Investigation of the cause of the malfunction: During the paving process, we found that all the movements of the paver were uniform and smooth. So we concluded that there was no fault in the circuit of the paver. Therefore, we focus our inspection on the mechanical and hydraulic aspects.

As our company is a construction unit and the parts of the paver are relatively expensive, coupled with the fact that the performance of this paver is relatively stable and our company does not store any non-essential parts, under such circumstances, we can adopt the interchangeability method to troubleshoot the problem based on the fact that the structure and components of this paver are basically symmetrically distributed.

(1) During the paving process, the screed was not in close contact with the already formed road surface, and there was a feeling of the screed jumping up and down. Therefore, we first checked the installation issue of the screed. After inspection, it was found that the operator, in order to save time and effort during the installation of the screed, artificially did not install the bottom set of fixing screws of the screed, and the tightness of the installed screws was insufficient. At the same time, it was found that the vibration eccentric shaft of the ironing plate was not assembled correctly in accordance with the requirements of the manual during the installation process, but was simply assembled together. After the correct installation of the ironing plate and the vibration shaft, the machine was restarted for paving operations. It was found that except for the weakened vibration of the ironing plate, the other faults still existed.

(2) We adopted the non-contact balance beam made in Denmark. After the machine was shut down, we swapped all the probes and control boxes on both sides of the balance beam and restarted the machine to carry out the paving operation. However, it was found that the fault still persisted on both sides.

(3) After swapping the anti-climbing and anti-lowering locks of the ironing plate on the left and right sides and starting the machine for spreading operations, the fault still persisted.

(4) The hydraulic pressure of the leveling cylinders on both sides was measured and found to be normal. After replacing the solenoid valve and hydraulic lock assembly of the leveling cylinders, the machine was restarted for paving operations, but the fault persisted.

(5) After swapping the left and right sides of the leveling cylinder, the machine was restarted for paving operations. It was found that the fault had shifted from the original left side to the right side. Therefore, it was discovered that internal leakage of the leveling cylinder was the main cause of this fault. The fault was eliminated after replacing the cylinder.