Microaggregate‐bitumen interactions in asphalt mixtures cause nonuniform rheological properties of bitumen adhering to aggregates. It is necessary to quantify microaggregate‐bitumen interactions so that the properties of the confined bitumen can be precisely characterized. This study developed a viscosity model of confined bitumen film considering microsubstrate–bitumen interactions. An exponential function was introduced to characterize the spatial distribution of viscosity under the effects of these microinteractions. The apparent viscosity of the bitumen film was formulated as an expression of thickness comprising bulk and interfacial viscosities and a decay index. The bulk viscosity showed a temperature dependence that corresponded with the Williams–Landel–Ferry model. The interfacial viscosity was higher than the bulk viscosity at high temperatures but lower at low temperatures, which indicates that the effect of substrate–bitumen interactions is bidirectional and depends on temperature. This phenomenon could be attributed to the microstructural transition of interfacial bitumen from an oriented layer to a disentangled one. Molecular dynamics simulations demonstrated the microstructural changes of interfacial bitumen under the effect of microaggregate‐bitumen interactions.

中文翻译：

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考虑微骨料-沥青相互作用的密闭沥青的粘度表征

沥青混合物中的微骨料-沥青相互作用会导致粘附到骨料上的沥青流变特性不均匀。有必要对微骨料-沥青相互作用进行量化，以便能够精确表征承压沥青的性质。这项研究考虑了微基质与沥青的相互作用，建立了一个封闭沥青膜的粘度模型。引入指数函数来表征在这些微相互作用的作用下粘度的空间分布。沥青膜的表观粘度被表示为包括体积和界面粘度以及衰减指数的厚度表示。体粘度显示出与威廉姆斯-兰德尔-费里模型相对应的温度依赖性。在高温下，界面粘度高于整体粘度，而在低温下，界面粘度较低，这表明底物-沥青相互作用的影响是双向的，并取决于温度。这种现象可归因于界面沥青从定向层到非缠结层的微观结构转变。分子动力学模拟表明，在微骨料-沥青相互作用的作用下，界面沥青的微观结构发生了变化。