How to check the material distribution of the paver?

1. Inspection before construction
1. Check the spiral distributor: Check whether the blades of the spiral distributor are installed correctly and intact, whether the spiral shaft rotates flexibly, and whether there is any deformation or wear. If the blades are damaged, deformed or missing, it will affect the pushing and distribution of the material; if the spiral shaft rotates inflexibly, it will cause uneven material transportation. For example, if the blades are cracked or deformed, they cannot drive the material normally during rotation, causing problems in material distribution.
2. Adjust the scraper chain: Ensure that the tension of the scraper chain is moderate and the connection between the scraper and the chain is firm. If the scraper chain is too loose, the material transportation will be weak and cause material accumulation; if it is too tight, it will increase the wear of the chain and the scraper, and even cause the chain to break. At the same time, check the wear of the scraper. Excessive wear of the scraper will affect the scraping effect of the material, and then affect the material distribution.
3. Check the screed: Check whether the bottom surface of the screed is flat and smooth, and whether there is any deformation, wear or sticking. An uneven screed will cause an uneven road surface after paving, affecting the uniformity of material distribution. If there is material on the screed plate, the friction between the screed plate and the material will increase, affecting the paving effect of the material.
2. Inspection during construction
1. Observe the flow of materials: When the paver is operating, observe the entire flow process of the material from the hopper to the spiral distributor through the scraper, and then to the front of the screed plate. Check whether the material flows continuously and evenly, and whether there is any blockage, interruption or accumulation. For example, if the material is found to be accumulated at the spiral distributor, it may be that the speed of the spiral distributor is not appropriate or the blade angle is problematic; if the material is accumulated in front of the screed plate, it may be that the height or elevation of the screed plate is improperly set.
2. Check the paving thickness: Use measuring tools such as a steel ruler or a thickness gauge to regularly measure the thickness of the pavement after paving. Measure at different locations, including both sides, the middle, and the joints of the paver, to ensure that the paving thickness meets the design requirements. If the paving thickness is uneven, it means that there is a problem with the material distribution and it needs to be adjusted in time. For example, if the paving thickness of a certain section is thicker on one side and thinner on the other side, it may be that the amount of material spread by the spiral distributor on that side is uneven.
3. Observe the flatness of the road surface: Check the flatness of the road surface after paving by visual observation or using flatness detection equipment, such as a laser flatness meter. If the road surface is wavy, pothole-like, or uneven, it means that the material is unevenly distributed, resulting in uneven force on the screed during paving. For example, uneven distribution of materials under the screed will cause the screed to sink differently at different locations, thus affecting the flatness of the road surface.
4. Check the material temperature: Use a thermometer to measure the temperature of the material to ensure that the material temperature is within the appropriate range. Too high or too low material temperature will affect its fluidity and paving effect, leading to uneven material distribution. For example, materials with too high a temperature are easy to flow and difficult to control their distribution; materials with too low a temperature will become viscous and difficult to spread evenly.
3. Inspection after construction
1. Core sampling: After paving is completed, core sampling is performed on the road surface to observe the distribution of materials in the core sample. Check whether the distribution of aggregate and asphalt in the core sample is uniform and whether there is segregation. If there is obvious aggregate concentration or asphalt enrichment area in the core sample, it means that the material is unevenly distributed during the paving process.
2. Compactness test: Use compaction test equipment, such as nuclear density meter or sand filling method, to test the compaction of the road surface. Uneven compaction may be caused by uneven material distribution. For example, the compaction is lower in areas with less material distribution, while the compaction is higher in areas with more material distribution.
3. Observe the appearance of the road surface: Carefully observe the appearance of the road surface to check for obvious segregation marks, color difference or uneven texture. Segregation can cause appearance defects such as whitening and roughness on the road surface, affecting the quality and appearance of the road surface. For example, in areas where material segregation is serious, the color of the road surface will become significantly lighter and the surface texture will be unclear.