重庆交通大学土木工程学院 重庆,400074
U416.214??
School of Civil Engineering of Chong Qing JiaoTong Univesity,Chongqing,China,400074
考虑到沥青老化的本质是化学结构的变化，首先选用氢化还原剂三乙氧基硅烷将老化沥青中的强极性羰基和亚砜基还原成羟基，同时生成极性较低的酯或者醚，再用端基钝化剂异氰酸酯与羟基进行酯化反应，实现端基钝化。通过测试老化沥青各修复阶段的化学结构与极性变化，探究其修复机理；进而以基质沥青为参比，分析测试老化沥青性能修复前后的动力粘度和低温性能，评价氢化还原与端基钝化对老化沥青的化学修复效果。结果表明，氢化还原与端基钝化使老化沥青的化学结构发生了本质的变化，三乙氧基硅烷可将老化沥青中羰基和亚砜基还原成羟基，异氰酸酯可将羟基通过酯化反应生成酯；经氢化还原与端基钝化之后，老化沥青的极性显著减弱，分子间作用力和粘度明显降低，低温性能得以显著改善；劲度模量和蠕变速率与老化沥青的官能团指数之间具有良好的对应关系。
In considering of the aging process of asphalt causing the change in its chemical structure, triethoxy silane is used to reduce the strong polar carbonyl group and sulfoxide group in aged asphalt to hydroxyl group , and the ester or ether with low polarity is generated at the same time, then hydroxyl group is esterified with the end group deactivator isocyanate to achieve the end group deactivation. The chemical repair mechanism was explored through testing the chemical structure and polarity changes of aged asphalt in each repair stage. Using matrix asphalt as a reference, the chemical repair effect of hydrogenation reduction and end-group deactivation on aged asphalt was evaluated by analyzing and testing the dynamic viscosity and low temperature properties of aged asphalt before and after repair. The results show that the chemical structure of aged asphalt is changed by hydrogenation and passivation. The carbonyl group and sulfoxide group in aged asphalt has been reduced to hydroxyl group by triethoxylsilane, then the hydroxyl group has been esterified to ester by isocyanate. After hydrogenation and passivation, the polarity of aged asphalt is significantly weakened, and the intermolecular force and viscosity are significantly reduced, so the low temperature performance is significantly improved. There is a good correspondence between stiffness modulus and creep rate and functional group index of aged asphalt Key words: hydrogenation reduction; end group deactivation; aged asphalt; Polarity; dynamic viscosity; low temperature bending property
