冻融循环下沥青特征官能团含量与流变参数灰熵分析及微观形貌

Micro-morphology and gray entropy analysis of asphalt characteristics functional groups and rheological parameters under freeze-thaw cycles

为了更好地将沥青化学组分变化与沥青路用性能联系起来,提高寒区沥青路面的耐久性。本文联合傅里叶变换红外光谱(FTIR)和动态剪切流变(DSR)测试技术,基于灰色关联熵分析数学模型,探讨了冻融循环下沥青流变特性参数和特征官能团含量的变化情况及其关联程度,结合扫描电子显微镜(SEM)表征了冻融循环前、后沥青结构的微观形貌变化情况。研究结果表明:沥青在冻融循环下,发生了水-温老化反应;不同冻融循环次数下,沥青FTIR谱图中亚砜基与羰基呈现出明显增大的趋势、沥青复数剪切模量对数值随温度的升高呈现出负线性增长的趋势、相位角随温度的升高呈现线性增长的趋势、抗车辙因子随温度的升高呈现指数衰减的趋势;沥青化学组分变化对流变特性参数影响程度由大到小的排序为:羰基、芳香族化合物、非对称脂肪族化物、脂肪族化物、亚砜基;基质沥青经过水冻融循环后,沥青膜结构出现明显的褶皱和絮状区。

In order to better link the chemical analysis with the pavement performance of asphalt binders,improve the durability of asphalt pavement in cold areas,Fourier Transform Infrared Spectroscopy（FTIR）and Dynamic Shear Rheological（DSR）test were used to analyze the changes of asphalt rheological parameters and characteristic functional groups under freeze-thaw cycles.The relationship between the rheological properties and the content of characteristic functional groups of asphalt was discussed based on gray relational entropy analysis model.The microstructure of the asphalt before and after the freeze-thaw cycle was characterized by Scanning Electron Microscopy（SEM）.Results show that water-temperature aging reaction occurs in the asphalt during the freeze-thaw cycles.Under different freeze-thaw cycles,the sulfoxide and carbonyl groups in the asphalt FTIR spectrum show a significant increase.The logarithm of asphalt complex modulus has a negative growth relationship with the increase in temperature.The phase angle changes linearly with the temperature.The rutting factor exhibits and exponential decay pattern with temperature.The asphalt chemical compositions influence the rheological properties in the order carbonyl,asymmetric aliphatic,sulfoxide.The asphalt film structure appears obvious folds and flocculent areas after water freezethaw cycles.