Variability of gradation for asphalt mixture is always the difficulty faced by the control of pavement construction, involving the pavement performance. The main purpose of this study is to improve the efficiency of detection for gradation variation and clarify the relationship between gradation variation and construction process. The variability of gradation for superpave asphalt mixtures was investigated with nominal maximum aggregate size (NMAS) of 13 mm, 20 mm, and 25 mm in construction. The correlation between the passing percentages at each sieve size and performance of asphalt mixture was first established by coupling grey relational analysis and entropy weight method. A digital image processing technology with multi-thresholds segmentation (DIP-MTS) was developed and verified through the experiment comparison. An approach to reversely calculate the gradation of cold aggregate was established. The mixture gradations during various construction stages were compared. Results illustrate that the passing percentages of sieves with NMAS, 4.75 mm, and 0.075 mm have a significant influence on the pavement performance and should be paid more attention during construction. The detection results of DIP-MTS are closer to the experimental value, and this technology is capable of detecting gradation for moving aggregate. The reverse calculation approach is proved feasible. Gradation variation in transportation is more severe than other construction processes.

沥青混合料的级配变化始终是控制路面结构所面临的难题，涉及路面性能。这项研究的主要目的是提高层次变化的检测效率，并弄清层次变化与施工过程之间的关系。研究了超级铺装沥青混合料的等级变化，其标称最大集料尺寸（NMAS）为13 mm，20 mm和25 mm。首先通过灰色关联分析和熵权法相结合，建立了各筛分通过率与沥青混合料性能之间的相关性。通过实验比较，开发并验证了一种具有多阈值分割的数字图像处理技术（DIP-MTS）。建立了一种反向计算冷骨料等级的方法。比较了各个施工阶段的混合灰阶。结果表明，采用NMAS，4.75 mm和0.075 mm筛分的筛分合格率对铺装性能有显着影响，在施工期间应引起更多注意。DIP-MTS的检测结果更接近实验值，该技术能够检测出移动骨料的灰度。反向计算方法被证明是可行的。运输中的等级变化比其他施工过程更为严重。075 mm对铺装性能有重大影响，在施工期间应引起更多注意。DIP-MTS的检测结果更接近实验值，该技术能够检测出移动骨料的灰度。反向计算方法被证明是可行的。运输中的等级变化比其他施工过程更为严重。075 mm对铺装性能有重大影响，在施工期间应引起更多注意。DIP-MTS的检测结果更接近实验值，该技术能够检测出移动骨料的灰度。反向计算方法被证明是可行的。运输中的等级变化比其他施工过程更为严重。