复合老化作用下沥青及沥青混合料损伤自愈合行为研究

The utilization rate of asphalt pavement in highway of our country is as high as 90%, the asphalt pavement undergoes the aging process during service life by the comprehensive effect of light, heat, oxygen and water,cracking and localized damage happened inevitably, however,the interfacial healing of asphalt materials occurs spontaneously in the crack initiation and propagation process due to environmental change. At present, asphalt self-healing potential has not yet been considered in the optimization design and life prediction of pavement,study on self-healing performance of asphalt materials after aging is very little involves ,therefore, the accurate evaluation of self-healing ability of asphalt and asphalt concrete after composite aging can optimize the application of asphalt material on the economy.In this study, asphalt and asphalt mixture before and after aging are regarded as the research object, the composite aging test and self-healing test will designed considering the regional climate condition,and the material mechanical properties and microstructure change will analysis by micro test methods, the damage and self-healing behavior evaluation index of asphalt and mixture will proposed after considering damage degrees,damage and healing behavior equation will established to evaluation asphalt and asphalt concrete,the effects of nano-additives on aging and self-healing properties of asphalt material will studied,all those can provide reference for optimization design of high quality and durability asphalt pavement.

我国高速公路中沥青路面的使用比例高达90%，沥青路面在长期服役过程中受光、热、氧、水等各种因素的综合作用会发生老化，不可避免地出现开裂和局部损伤，而沥青材料在裂纹萌生与扩展过程中会由于环境变化自发进行界面愈合。目前沥青的自愈潜能还没有在路面的优化设计和寿命预测中加以考虑，自然环境综合作用下沥青材料的老化和自愈性能研究较少，因此准确评价复合老化后沥青和沥青混凝土的的自愈能力，可以在经济上优化沥青材料的使用。本研究以复合老化前后的沥青和沥青混合料为研究对象，结合区域气候条件设计复合老化试验及自愈合试验，并采用微细观测试手段对材料的力学性能及微细观结构变化进行分析，提出考虑损伤程度的沥青及混合料损伤自愈行为评价指标,以期从流变学和宏细观力学角度合理解释自愈合机理，建立评价沥青及沥青混凝土的损伤愈合的行为方程，并考察纳米添加剂对沥青材料老化及自愈性能的影响，为高质量耐久性沥青路面的优化设计提供参考

沥青路面在长期服役过程中受光、热、氧、水等各种因素的作用会发生老化，不可避免地出现开裂和局部损伤，而沥青材料在裂纹萌生与扩展过程中会由于环境变化自发进行界面愈合。本研究以老化前后的沥青和沥青混合料为研究对象，通过定制设备结合区域气候条件合理设计复合老化实验，并提出采用低温劲度模量变化率SV作为评价老化的新指标；采用动态剪切流变和四点弯疲劳等试验手段设计沥青材料的疲劳自愈合实验，并采用表象法和能量法建立自愈合评价指标，以评价复合老化后沥青材料的自愈能力；采用AFM、SEM、NMR、DIC等微细观测试手段对沥青材料的微细观结构变化进行观测，深入剖析复杂环境下沥青材料的老化及自愈合机理；考察SBS、胶粉、纳米添加剂等对沥青材料老化及自愈性能的影响,发现改性剂可很好地提高沥青的抗老化和抗疲劳性能，但会一定程度上限制沥青的愈合；采用灰关联等方法，建立环境影响下材料宏观性能指标与微观结构指标之间的关联性，评价了微观指标的可靠性，拓展了沥青类材料的检测手段;以上研究从多尺度评价热老化、水老化、紫外老化、复合老化等状态下沥青及沥青混合料结构变化、性能劣化和主动恢复的基本规律，得出沥青种类、添加剂、老化程度、愈合温度、愈合时间、损伤程度等因素对沥青混合料性能的影响，可为道路工程提供养护策略，延长公路服役期并提升其使用性能。