ABSTRACT

The use of reclaimed asphalt pavement (RAP) in road construction has become a common practice in the asphalt industry due to environmental and economic benefits. However, since RAP is an aged material, recycling agents are typically used to reduce the stiffness of the recycled asphalt mixture and make it less prone to cracking at high RAP contents. This study evaluates the effect of ageing and the use of recycling agents on the rheological, microstructural, and micromechanical properties of binder blends with high RAP contents. A total of 27 binder blends were prepared with different recycled binder ratios (0.22, 0.31 and 0.5), recycling agent doses (0%, 1.2%, 5.5% and 9%), virgin binder performance grades (PG 58-28 and PG 52-34) and ageing conditions. The microscopic properties of the binder blends were characterised using atomic force microscopy (AFM). AFM results provided an evaluation of the microstructural homogeneity of the blends, with a good correlation with the binder blends macroscopic rheological properties. The addition of recycling agents improved the homogeneity of the binder blends by reducing the variation in modulus among the different phases in the microstructure. AFM proved to be a useful tool to evaluate rejuvenated binder blends at the microscale level.

摘要

由于环境和经济效益，在道路建设中使用再生沥青路面（RAP）已成为沥青行业的普遍做法。然而，由于 RAP 是一种老化材料，回收剂通常用于降低回收沥青混合物的刚度，并使其在高 RAP 含量下不易开裂。本研究评估了老化和再生剂的使用对高 RAP 含量的粘合剂混合物的流变、微观结构和微观机械性能的影响。总共制备了 27 种粘合剂混合物，它们具有不同的回收粘合剂比率（0.22、0.31 和 0.5）、回收剂剂量（0%、1.2%、5.5% 和 9%）、原始粘合剂性能等级（PG 58-28 和 PG 52） -34) 和老化条件。使用原子力显微镜 (AFM) 表征粘合剂共混物的微观性质。AFM 结果提供了对共混物微观结构均匀性的评估，与粘合剂共混物的宏观流变性能具有良好的相关性。添加回收剂通过减少微观结构中不同相之间的模量变化来改善粘合剂共混物的均匀性。事实证明，AFM 是一种有用的工具，可以在微尺度水平上评估再生粘合剂混合物。添加回收剂通过减少微观结构中不同相之间的模量变化来改善粘合剂共混物的均匀性。事实证明，AFM 是一种有用的工具，可以在微尺度水平上评估再生粘合剂混合物。添加回收剂通过减少微观结构中不同相之间的模量变化来改善粘合剂共混物的均匀性。事实证明，AFM 是一种有用的工具，可以在微尺度水平上评估再生粘合剂混合物。