Yang Jun, Yi Xingyu, Chen Huimin, Wong Yiik Diew, Fan Yulou, Huang Wei
School of Transportation, Southeast University, Nanjing 210096, China.
School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore.
Polymers (Basel). 2023 Oct 30;15(21):4261. doi: 10.3390/polym15214261.
The utilization of reclaimed asphalt pavement (RAP) could reduce the cost of pavements containing epoxy polymer (EP) materials. This study was aimed at improving the homogeneity of an EP-reclaimed asphalt mixtures (ERAMs) at both the micro- and meso-scale to provide a reference for an ERAM production process. At the microscale, nanoindentation tests were conducted to characterize the diffusion between the EP and aged asphalt mastic. At the mesoscale, computerized tomography (CT) X-ray scanning and MATLAB analysis were employed to investigate the distribution of the aggregate within the ERAM. The results revealed that mixing temperature played a significant role in the diffusion and distribution between the EP and the aged asphalt mastic, thus impacting the mechanical properties of the material. Heating at 180 °C (the recommended mixing temperature of EP) resulted in a wider blending zone between the EP and the aged asphalt mastic compared to heating at 160 °C (the usual mixing temperature of ordinary reclaimed asphalt mixtures). The overall dispersion of the aggregate in the ERAM exhibited greater homogeneity in the vertical direction than in the horizontal direction. Adjusting the gradation of the RAP was found to be effective in reducing horizontal variability in the distribution of the coarse aggregate, fine aggregate, and air voids in the ERAM. Adjusting the RAP gradation further enhanced the vertical homogeneity in the distribution of the fine aggregate, while its impact on the vertical distribution of the coarse aggregate was minimal. Short-term aging led to increased variability in the distribution of the coarse aggregate, fine aggregate, and air voids within the ERAM. However, adjusting the gradation was effective in mitigating the adverse effects of short-term aging on both horizontal and vertical homogeneity in the aggregate distribution.
再生沥青路面（RAP）的利用可以降低含环氧聚合物（EP）材料路面的成本。本研究旨在提高EP再生沥青混合料（ERAM）在微观和细观尺度上的均匀性，为ERAM生产工艺提供参考。在微观尺度上，进行纳米压痕试验以表征EP与老化沥青胶浆之间的扩散。在细观尺度上，采用计算机断层扫描（CT）X射线扫描和MATLAB分析来研究ERAM内集料的分布。结果表明，拌和温度在EP与老化沥青胶浆之间的扩散和分布中起着重要作用，从而影响材料的力学性能。与在160℃（普通再生沥青混合料的常用拌和温度）下加热相比，在180℃（EP的推荐拌和温度）下加热会使EP与老化沥青胶浆之间的混合区更宽。ERAM中集料的整体分散在垂直方向上比在水平方向上表现出更大的均匀性。发现调整RAP的级配可有效降低ERAM中粗集料、细集料和空隙分布的水平变异性。进一步调整RAP级配可增强细集料分布的垂直均匀性，而其对粗集料垂直分布的影响最小。短期老化导致ERAM内粗集料、细集料和空隙分布的变异性增加。然而，调整级配可有效减轻短期老化对集料分布水平和垂直均匀性的不利影响。
