基于Arrhenius方程的老化沥青流变特性

发布时间：2018-09-14 09:25

【摘要】：为了研究沥青老化过程中的流变特性,选择5种沥青分别进行不同时间的旋转薄膜烘箱老化试验(RTFOT),分别采用Brookfield黏度计和低温弯曲梁流变仪(BBR),对不同老化状态的沥青样品进行旋转黏度和低温流变参数测定。根据不同温度下的黏度试验,提出采用Arrhenius方程计算沥青黏流活化能Eη的方法,讨论沥青老化过程中Eη的变化规律;并分析低温劲度模量及其随时间的变化率m与RTFOT老化时间的关系,讨论老化沥青的黏流活化能与m的关系。研究结果表明:通过Arrhenius方程可以计算得到不同老化状态沥青的黏流活化能Eη,用以表征沥青的流变性能和感温性;随着老化程度的加深,Eη不断增大,即老化对沥青的流变行为有显著影响,沥青老化后分子结构变化引起流动能量增加,柔韧性减弱;虽然老化后沥青的黏度值和黏流活化能都不断增加,但二者大小没有必然联系,黏度随温度的变化才是沥青流变性能的反映;不同沥青在RTFOT老化0~85、85~180、180~360min不同阶段的黏流活化能增大速率存在较大差别,反映了其抗老化性能和老化机理的差异;沥青抵抗短期老化和长期老化的能力并不一致,SK(韩国SK-110)和ZHH(中海-90)具有优良的抗短期老化性能,而ESSO(埃索-90)和SK抗长期老化性能最好;随着老化程度的加深,沥青样品的黏流活化能与低温蠕变劲度变化率呈较好的负相关性,即沥青的黏流特性与低温蠕变行为密切相关。
[Abstract]:In order to study the rheological properties of asphalt during aging, Five kinds of asphalts were selected for different time rotating film oven aging tests. (RTFOT), was used to measure the rotational viscosity and low temperature rheological parameters of asphalt samples with Brookfield viscometer and low temperature bending beam rheometer (BBR),) respectively. According to the viscosity test at different temperatures, the method of calculating the activation energy E 畏 of asphalt viscosity flow by Arrhenius equation is put forward, and the variation law of E 畏 during asphalt aging is discussed. The relationship between the low temperature modulus of stiffness and the rate of change with time m and the aging time of RTFOT is analyzed, and the relationship between the viscosity flow activation energy and m of aging asphalt is discussed. The results show that the viscous flow activation energy E 畏 of asphalt with different aging states can be calculated by Arrhenius equation, which can be used to characterize the rheological property and temperature sensitivity of asphalt, and the E 畏 increases with the increase of aging degree. That is, aging has a significant effect on the rheological behavior of asphalt. After aging, the flow energy increases and the flexibility decreases due to the change of molecular structure, although the viscosity and the activation energy of viscosity increase continuously after aging. However, the change of viscosity with temperature is the reflection of rheological properties of asphalt, and the increasing rate of viscous flow activation energy of different asphalts at different stages of RTFOT aging is quite different. The results show that the resistance of asphalt to short term aging and long term aging is not consistent with that of SK (Korea SK-110) and ZHH (Zhonghai 90), while ESSO (Esso 90) and SK have the best long term aging resistance. With the aging degree deepening, the viscosity flow activation energy of asphalt samples has a good negative correlation with the creep stiffness change rate at low temperature, that is, the viscosity flow characteristics of asphalt are closely related to the creep behavior at low temperature.
【作者单位】：长安大学道路结构与材料交通行业重点实验室;
【基金】：国家自然科学基金项目(51008031) 交通运输部应用基础研究项目(2014319812151) 陕西省自然科学基础研究计划项目(2014JQ7242) 中央高校基本科研业务费专项资金项目(310821162010,310821163404)
【分类号】：U414

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