【作者】 朱国军；

【导师】 吴少鹏； 文进；

【作者基本信息】 武汉理工大学 ， 材料学， 2009， 硕士

【摘要】 公路交通是国民经济和社会发展的命脉。截至2008年底,我国高等级公路通车里程超过6.03万公里,逐步形成东部加密、中部成网、西部连通的交通体系。高速公路服役期间,对沥青路面性能的要求越来越高;然而沥青的老化、挥发物的衰减、自然硬化及渗流必将导致路面使用性能的下降;其中太阳光、氧气是诱发沥青老化及沥青路面性能下降的主要因素。本文研究光氧因素对沥青及沥青混凝土性能的影响,探讨沥青及沥青混凝土在光氧老化作用下沥青化学组分及其结构性能的演变规律。本文对以往研究成果总结的基础上,选取基质沥青AH70和SBS改性沥青PG76-22为研究对象,运用布氏粘度仪、四组分分析、傅立叶红外光谱分析仪、原子力显微镜及动态剪切流变仪等检测分析手段,研究沥青在光氧老化作用下的路用性能、化学组分、化学结构及流变性能的室内外老化演变规律。研究发现:室内外老化性能演变趋于一致;光氧老化使沥青路用性能的粘度增加、温度敏感性降低、高温性能增强;光氧老化使沥青的轻质组分减少,胶质、沥青质增多,同时羰基和亚砜基指数显著增加,形成较多的分子量相对较大的沥青质;SBS改性沥青PG76-22中,C=C峰值含量减少,表明改性剂降解;光氧作用增大了沥青复合剪切模量G~*和相位角δ减小,使沥青弹性增强;同时发现,沥青老化与沥青膜厚成反比、老化时间、光强度成正比。本文选用SBS改性沥青PG76-22合成AC-13及SMA-13级配沥青混凝土进行沥青混凝土光氧老化性能研究,采用低温三点弯曲实验和四点弯曲疲劳试验检测沥青混凝土老化过程中的性能变化;研究表明:低温弯曲强度随老化程度减小,老化程度越高,其减小的变化趋势越快;室内外老化条件下弯曲劲度模量与老化时间之间呈现近似相同的变化趋势;通过计算小梁试件的弯拉断裂能判定在短期老化及路面老化12个月附近,沥青混凝土AC-13和SMA-13具有最大的弯曲应变能;运用现象学法和耗散能疲劳理论,对比研究两种级配结构的抗老化、抗疲劳特性,发现SMA-13的抗老化及抗疲劳特性均优于AC-13级配结构;材料的累积耗散能均与疲劳寿命成正比;材料老化时间越长,应变越大,其疲劳寿命越短。更多还原

【Abstract】 Road transportation is the lifeline of national economy and social development. Up to the end of 2008,over 60.3 thousand kilometers high-grade highway pavement in China has been opened to traffic,which has gradually formed a traffic system of "encryption into a network of the eastern part of west central connectivity".The demand for a high standard pavement performance during the service period of highway pavement is increasing.Meanwhile,the pavement performance is apparently deteriorating with asphalt aging,volatile attenuation,natural hardening and asphalt flow.Among them,sunlight and oxygen are the main reasons for the degradation of asphalt pavement performance.This paper explored the influence of UV elements on asphalt property,as well as the changing rules of chemical components and construction of asphalt or asphalt concrete under the condition of UV aging.Based on the conclusion of previous research,choosing based asphalt AH70 and SBS modified PG76-22 as objects,the paper examined the indoor and outdoor aging of road performance,chemical composition,chemical structure and rheological properties with analyzing methods of Brookfield viscosity, four-component analysis,Fourier Transform Infrared(FTIR),Atomic Force Microscopy(AFM) and Dynamic Shear Rheometer(DSR),etc.The findings are as follows:the rules of indoor and outdoor aging are almost the same;oxygen aging makes the viscosity of asphalt road performance incresed and temperature sensibility decreased,the light components in asphalt decreased and colloid,asphaltene increased;at the same time,the index of carbonyl and sulfoxide-base ascended remarkably,leads to the formation of more asphaltene with comparatively bigger molecular weight;in modified asphalt PG76-22,the content of butadiene functional group has reduced with the decomposition of SBS modified;the UV action contributes to the increment of asphalt complex modulus G* and the reduce of phase angleδand makes asphalt stiffer;asphalt aging rises proportionately to the asphalt thickness,aging time and aging intensity.The paper inspected the property changes during the aging process by low temperature three-point bending test and four-point bending fatigue test,with SBS modified asphalt PG76-22,compound AC-13 and SMA-13 gradation asphalt concrete as materials.By conclusion,we find that the bending intensity rose at first and then fell with the reinforcement of aging extend.The higher the aging degree is, the faster the falling of bending intensity.The bending stiffness modulus of indoor aging exhibits a nearly same variation law with aging time.By caculating the bending fracture energy of specimens,asphalt is proved to have the biggest bending strain energy in short time aging or around 12 months service.We also find that the anti-aging and anti-fatigue properties of SMA-13 are superior to AC-13 gradation construction by a comparing research based on phenomenology and dissipative energy fatigue theories.The cumulative dissipated energy of materials varies directly with fatigue life,while the latter becomes shorter with the increment of aging time and strain.更多还原