Different microstructures of the same polymer-modified bitumen (PMB) were obtained by subjecting the bitumen modified with styrene-butadiene-styrene (SBS) copolymer to isothermal annealing at various temperatures. The effects of the morphology on the rheological properties of SBS-modified bitumen were investigated within the high-temperature range. The PMB microstructures were quantitatively evaluated using image analysis. A dynamic shear rheometer was used to measure the rheological parameters of the PMB samples and perform the multiple stress creep and recovery (MSCR) test. A quantitative basis could be established on which to discuss the relationship between the PMB morphology and rheology. The image analysis indicated that conditioning by isothermal annealing evidently led to a difference in the microstructure of the samples. Variation of the thermal history is demonstrated to be a practical way to vary the morphology of the PMB with the same raw materials and formulation. Compared with the two-phase morphology, the single-phase microstructure tended to have a narrower linear viscoelastic (LVE) region of the PMB. Within the LVE region, especially at low frequencies, the homogenous PMB can store more energy when experiencing loadings and is more elastic. Outside the LVE region, based on the MSCR test results, the homogenous morphology could assist in reaching a higher percentage of strain recovery after the creep period.

通过将用苯乙烯-丁二烯-苯乙烯 (SBS) 共聚物改性的沥青在不同温度下进行等温退火，获得相同聚合物改性沥青 (PMB) 的不同微观结构。在高温范围内研究了形貌对 SBS 改性沥青流变性能的影响。使用图像分析定量评估 PMB 微结构。动态剪切流变仪用于测量 PMB 样品的流变参数并进行多应力蠕变和恢复 (MSCR) 测试。可以建立一个定量基础来讨论 PMB 形态和流变学之间的关系。图像分析表明，等温退火调节明显导致样品微观结构的差异。热历程的变化已被证明是改变具有相同原材料和配方的 PMB 形态的实用方法。与两相形态相比，单相微观结构倾向于具有更窄的 PMB 线性粘弹性 (LVE) 区域。在 LVE 区域内，尤其是在低频时，均质 PMB 在承受载荷时可以存储更多能量并且更具弹性。在 LVE 区域之外，根据 MSCR 测试结果，均匀的形态有助于在蠕变期后达到更高的应变恢复百分比。单相微观结构倾向于具有较窄的 PMB 线性粘弹性 (LVE) 区域。在 LVE 区域内，尤其是在低频时，均质 PMB 在承受载荷时可以存储更多能量并且更具弹性。在 LVE 区域之外，根据 MSCR 测试结果，均匀的形态有助于在蠕变期后达到更高的应变恢复百分比。单相微观结构倾向于具有较窄的 PMB 线性粘弹性 (LVE) 区域。在 LVE 区域内，尤其是在低频时，均质 PMB 在承受载荷时可以存储更多能量并且更具弹性。在 LVE 区域之外，根据 MSCR 测试结果，均匀的形态有助于在蠕变期后达到更高的应变恢复百分比。