废机油残留物再生沥青的抗老化性能

Anti-aging Performance of Recycled Engine Oil Bottom Rejuvenated Asphalt

以废机油残留物(REOB)作为沥青再生剂,从REOB自身、REOB再生沥青及REOB再生沥青混合料3个层次进行老化性能研究.通过延时薄膜烘箱老化试验(TFOT)(老化时间分别为5、10、15、20、25h),测定了REOB再生沥青、RA5再生沥青和基质沥青的质量及黏度变化,并采用弯曲梁流变试验评定3种沥青老化后的低温性能;利用对应的3种沥青混合料设计铺筑了室内足尺试验路面层,并采用自主研发的回转式加速加载试验系统(RALT)在常温及高温下开展了路面加速加载试验来评估其长期抗疲劳性能.结果表明:REOB再生沥青的抗短期老化性能(TFOT老化时间不超过10h)比RA5再生沥青好,但不如基质沥青,而其抗长期老化性能(TFOT老化时间不少于15h)最差;在长期老化后,REOB再生沥青因劲度急增且应力松弛性能骤降从而极易导致低温开裂;高温老化明显加剧了REOB再生沥青混合料路面在RALT加速加载条件下弯沉值的增长,使其在3种路面中最易发生疲劳破坏,说明将REOB用于再生沥青路面时,易使路面出现过早过度破坏.

Using recycled engine oil bottom(REOB)as asphalt rejuvenator,the aging performance was studied from three combinations:REOB,REOB-rejuvenated asphalt and REOB-rejuvenated asphalt mixture.The change of quality and viscosity of REOB-rejuvenated asphalt,RA5-rejuvenated asphalt and matrix asphalt were measured after extended thin film oven tests(TFOT)(aging times were 5,10,15,20,25h),and the low-temperature performance of three aged asphalts was evaluated by bending beam rheological tests.The corresponding three combinations of asphalt mixtures were used to design and pave surface layers of a full-scale indoor test road.A self-developed rotary accelerated loading test system(RALT)was used to carry out accelerated loading tests at room temperature and high temperature to evaluate the long-term fatigue performance of indoor asphalt pavement.The results show that the short-term aging resistance(TFOT aging time less than or equal to 10h)of REOB-rejuvenated asphalt is better than that of RA5-rejuvenated asphalt but worse than that of matrix asphalt,whereas the long-term aging resistance(TFOT aging time greater than or equal to 15h)of REOB-rejuvenated asphalt is the worst among the three tested asphalts.After long-term aging,REOB-rejuvenated asphalt is prone to cracking at low temperatures because of its rapid increase in stiffness and sharp decrease in stress relaxation performance.High-temperature aging significantly aggravates the increase of deflection value of REOB-rejuvenated asphalt pavement under long-term loading of RALT,which makes it most prone to fatigue failure among the three pavements.It is shown that when REOB is used in the rejuvenated asphalt pavement,it will easily cause premature and excessive damage to the pavement.