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Segregation during the construction of asphalt pavements is one of the key factors affecting pavement quality. The causes of segregation are complex, usually resulting from factors such as the paver’s structure, material feeding method, paving techniques, and the quality of the asphalt mixture. It has been proven that by exercising scientific and rational control over the construction process, the occurrence of segregation can be effectively reduced, thereby **improving the quality of asphalt pavements**. Separation is usually divided into aggregate separation and temperature separation. Aggregate segregation refers to the separation of larger-sized aggregates within an asphalt mixture, resulting in a clearly uneven mixing condition; it is generally caused by mechanical factors ； Temperature segregation refers to significant differences in temperature among various components within the asphalt mixture. The hazards of segregation are significant, as it can have various impacts on the quality of the road surface. The main causes of segregation in asphalt mixtures and the preventive measures are as follows: 1. Mixing (1) If the vibrating screen in the asphalt mixer is damaged in certain areas, the mixture may contain aggregates with sizes that exceed the specified limits; therefore, it is necessary to inspect this screen regularly and replace it when needed. (2) A short mixing time or leaves falling off in the mixer can also lead to uneven mixing and inconsistent temperatures. Therefore, the relevant components in the mixer should be checked regularly, the mixing time must be strictly controlled, and attention should be paid to whether there are any obvious accumulations of large and small aggregates in the mixture. If it is detected, the cause should be identified promptly and addressed right away. 2. Unloading: When the storage cylinder feeds material into the transport vehicle, due to gravity and height, the larger aggregates roll to the sides and front and back, resulting in the first concentration of aggregates. To change this situation, the materials should be stacked at the front, middle, and back of the transport vehicle respectively, so that the coarse and fine aggregates can be mixed again when discharging them into the dump truck. 3. Transportation: The jolts during transportation can also lead to the concentration of larger-sized aggregates. Meanwhile, since the surface of the material pile is in contact with air during transportation, its temperature drops rapidly, while the temperature at the center of the pile drops more slowly; this results in temperature segregation. Therefore, when selecting a location for the mixing site, it is necessary to ensure that the distance between the mixing site and the paving site is as short as possible. At the same time, the transportation routes should be properly leveled and the driving speed reduced, so as to minimize jolts during transportation ； Insulation measures should be taken for the material piles (especially during long-distance transportation), such as covering them with tarpaulins. 4. Dumping: When the mixture is unloaded onto the paver, the large aggregates roll to the sides of the hopper; therefore, the truck bed should be raised at a large angle and quickly so that the mixture can slide downward as a whole, thereby preventing the large aggregates from rolling outward and accumulating there. To address the issues in these 4 aspects, it is recommended to use mobile conveyors during construction; these conveyors are installed between the dump truck and the paver. The dump truck then pours the mixed material into the paver’s hopper, which helps to effectively prevent segregation of the aggregates and temperature-related segregation. In Europe and the United States, mobile conveyors are already being used in paving, and they play a significant role in reducing segregation. 5. The tilting of the paver’s hopper should be done properly – the wings of the hopper must be operated correctly, to absolutely avoid excessive accumulation of material inside the hopper as well as too rapid tilting. 6. Analysis of the spiral distributor: The main factor contributing to segregation in pavers is the spiral material distribution process, and the stage that consumes the most power during operation is also the spiral distribution process (accounting for approximately 50%-60% of the total power consumption of the machine). During the design of the paver, the power factor is taken into primary consideration, so that the surface of the material in the spiral distributor is located at 1/2 to 2/3 of the spiral diameter. Under such circumstances, when used for paving large widths and thick sections, the material flow rate increases; since only the part of the screw located inside the material has the ability to transport it, the rotation speed must be increased in order to meet the operational requirements. In this way, the top of the high-speed rotating and exposed spiral distributor throws the material into the space above the material layer. This is the main reason for segregation during the material separation process. This can be seen very clearly through observations at the construction site. Based on the above analysis, to prevent segregation in asphalt mixtures, the following measures should be taken during paving: use pavers equipped with screw spreaders of large diameter and low rotation speed (low-speed, high-torque motors) as much as possible ； Lower the height of the spiral distributor and ensure that the height of the mixture exceeds that of the spiral distributor (i.e., the distributor is fully buried in the mixture). This improves the conveying efficiency of the spiral distributor, reduces its rotational speed, and minimizes the differences in inertia among different material particles. Additionally, since the distributor is embedded within the mixture, it enables secondary mixing of the materials, thereby reducing the degree of segregation that occurs at the beginning. The distributor located within the mixture pushes the materials outward along the entire cross-section, rather than pushing them upward or downward; this helps to reduce lateral segregation at different widths as well as vertical segregation caused by the rolling of the materials. The upper part of the spiral distributor is not exposed to the air, so there is no risk of segregation in the surface layer due to upward movement of the materials. 7. Paving width: According to relevant data, when a paver with a paving width of 10.5 is used to pave the road surface, sampling tests show that aggregate segregation is quite severe; large aggregates account for 64% on the left and right sides of the road surface, while only 35% are found in the middle section, both values exceeding the specified gradation range. Therefore, when the paving width is large, multiple paving passes should be used, with each pass having a width of no more than 6–7 meters, which helps to reduce segregation. During paving, any segregation that occurs in the surface layer should be addressed promptly. If a manual fine screening method is used to obtain an appropriate amount of fine asphalt mixture, which is then spread on the surface layer where segregation has occurred and compacted promptly, this can help mitigate the effects of segregation.