基于原子力显微镜(AFM)的基质沥青老化前后形态变化及微观性能研究

Research on the morphologic change and micro-properties of matrix asphalt before and after aging based on atomic force microscope

采用旋转薄膜加热(RTFOT)和压力老化(PAV)制备克拉玛依90#短期和中长期老化沥青试样,通过原子力显微镜(AFM)测试老化前后沥青试样的形态变化及微观力学性能,并与其三大指标及高温流变性能建立关系。结果表明,老化使沥青样品在纳米尺度上的空间变异性显著增大,会在探针压痕过程中使样品变形所消耗的能力与总作用功之间的比值(PI)显著增大,并会导致沥青样品的黏结强度显著增大。且由模拟老化RTFOT和PAV引起的沥青剪切刚度增大与相位角减小均与PI增大具有良好的相关性。

The short and long-term aging Karamay asphalt samples were prepared by rotary film aging( RTFOT) and pressure aging( PAV) tests. The morphological changes and micro mechanical properties of asphalt samples were investigated adopting atomic force microscopy( AFM),before and after aging tests,which was taken to establish relationships with their high and low temperature rheological properties and three major indexes. The results show that the spatial variability of asphalt increases markedly at the nanoscale because of aging. What's more,aging makes the ratio of the energy consuming by samples deformation and total work in the probe indentation process( PI) increase significantly,which also leads to outstanding increasing of bonding strength of asphalt samples. The increasing shear strength and decreasing phase angle of asphalt by RTFOT and PAV have good correlation with increased PI.