萃取法生物油基再生沥青性能及再生机理

Performance and regeneration mechanism of bio-oil-based recycled asphalt by extraction method

为了研究萃取法生物油作为再生剂的可行性,采用自行研制的萃取法生物油基再生剂(SW)分别制备生物油基再生基质沥青和生物油基再生SBS改性沥青。通过常规性能试验、动态剪切流变和弯曲梁流变对2种再生沥青的性能进行评价,采用傅里叶红外光谱、凝胶渗透色谱分析2种沥青的再生机理。研究结果表明:添加掺量(质量分数)为8%、10%的SW再生剂均可将老化基质沥青和老化SBS改性沥青的三大指标和黏度恢复至原样沥青水平;在SW再生剂的作用下,老化基质沥青和老化SBS改性沥青的高温稳定性显著下降,低温抗裂性显著提升,且均能恢复至原样沥青水平;SW再生剂在老化沥青中主要以物理共混形式存在,但仍存在苯酚与甲醛缩聚和烯烃类物质氧化裂解等化学反应;SW再生剂富含大量轻质组分,对老化沥青具有显著的稀释作用;其所含的酚基化合物可促使老化沥青中的高分子量组分转化为小分子量组分,从而导致大分子物质和中分子物质质量分数降低,小分子物质质量分数增加,分散性指数减小,进而改善老化沥青组分的相容性和分子量分布。

In order to study the feasibility of extraction-based bio-oil as a rejuvenator,extraction-based bio-oil-based rejuvenator(SW)was developed to prepare bio-oil-based rejuvenated matrix asphalt and bio-oil-based regeneration SBS modified asphalt.The performances of the two rejuvenated asphalts were evaluated by conventional performance tests,dynamic shear rheology and bending beam rheology,and the regeneration mechanism of the two asphalts was analyzed by Fourier transform infrared spectroscopy and gel permeation chromatography.The results show that the three major indexes and viscosity of the aging matrix asphalt and the aging SBS modified asphalt with 8%and 10%content(mass fraction,the same below)SW rejuvenator agent are restored to the original asphalt level,respectively.Under the action of SW rejuvenator agent,the high-temperature stability of the aging matrix asphalt and the aging SBS modified asphalt decreases significantly,the low-temperature cracking resistance increases significantly,and both of them can be restored to the original asphalt level.The SW rejuvenator agent mainly exists in the form of physical blending in the aging asphalt,but there are still chemical reactions such as phenol-formaldehyde condensation and olefin oxidation cracking.The SW rejuvenator agent is rich in light components,which has a significant diluting effect on the aging asphalt.The phenolic compounds contain in the asphalt binder can promote the transformation of high molecular weight molecules into low molecular weight molecules,which leads to the decrease of the contents of macromolecular substances and medium molecular weight substances,the increase of small molecular weight substances,and the decrease of dispersion index,thereby improving the compatibility and molecular weight distribution of the components of aging asphalt.