ABSTRACT

Determining the permissible amount of reclaimed asphalt pavement (RAP) in new pavement mixes is a design challenge for pavement practitioners due to the limited understanding regarding the interaction between the aged and unaged binders in these mixtures. In this study, the solubility related molecular interactions of blended binders comprising of aged-unaged fractions was evaluated using an extension of the Hansen Solubility Parameter (HSP) model. Virgin binder was blended with aged binders from two different sources, at proportions of 15%, 30%, and 50%. These binder blends were evaluated using a method of titrations to identify their internal stability and relative extents of intermolecular interactions in terms of dispersive forces, hydrogen bonding, and polar interactions. The results implied that small proportions of aged binders have limited effect on the original stability of the unaged binders. Further Fourier transform infrared spectroscopy and gel permeation chromatography tests revealed that the oxidative elements in the blended binders increased with the increasing percentage of aged binders. It is theorized that these fractions will affect the polydispersity of the molecules through increased molecular associations. It is advised that incorporation of higher RAP contents in mixtures should ideally involve some consideration of the chemistries of the intermixing binders.

摘要

由于对这些混合物中老化和未老化粘合剂之间的相互作用的了解有限，确定新路面混合物中再生沥青路面 (RAP) 的允许量是路面从业者的设计挑战。在这项研究中，使用汉森溶解度参数 (HSP) 模型的扩展评估了由未老化部分组成的混合粘合剂的溶解度相关分子相互作用。原始粘合剂与来自两种不同来源的老化粘合剂以 15%、30% 和 50% 的比例混合。使用滴定方法评估这些粘合剂混合物，以确定它们的内部稳定性和分子间相互作用的相对程度，如分散力、氢键和极性相互作用。结果表明，小比例的老化粘合剂对未老化粘合剂的原始稳定性影响有限。进一步的傅里叶变换红外光谱和凝胶渗透色谱测试表明，混合粘合剂中的氧化元素随着老化粘合剂百分比的增加而增加。理论上，这些部分将通过增加分子缔合影响分子的多分散性。建议在混合物中加入较高的 RAP 含量，理想情况下应考虑到混合粘合剂的化学性质。进一步的傅里叶变换红外光谱和凝胶渗透色谱测试表明，混合粘合剂中的氧化元素随着老化粘合剂百分比的增加而增加。理论上，这些部分将通过增加分子缔合影响分子的多分散性。建议在混合物中加入较高的 RAP 含量，理想情况下应考虑到混合粘合剂的化学性质。进一步的傅里叶变换红外光谱和凝胶渗透色谱测试表明，混合粘合剂中的氧化元素随着老化粘合剂百分比的增加而增加。理论上，这些部分将通过增加分子缔合影响分子的多分散性。建议在混合物中加入较高的 RAP 含量，理想情况下应考虑到混合粘合剂的化学性质。