Microstructural characteristics of differently aged asphalt samples based on atomic force microscopy (AFM)

Abstract

In order to study how the microstructure of asphalt changes with aging time, this paper used ordinary oven to age 70 # virgin asphalt, the aging times were 0, 5, 10, 15, 25, 35, 45, 55, 65, and 75 h. By using atomic force microscope (AFM) PeakForce Tapping technology under the mode of QNM (PF - QNM), the surface morphology and mechanical behavior of asphalt with different aging times were tested by AFM, and the two-dimensional and three-dimensional morphology diagrams and mechanical behavior parameters of the asphalt samples were obtained. The quantity, roughness, height, adhesion force, modulus and other parameters of a single “bee structure” of asphalt were counted and analyzed. The results show that each “bee structure” in the asphalt is one of thousands of groups of asphalt structures. The “bee structure” can represent the four components of asphalt, and the adhesion force between the four components can represent the force between the colloid structures of the asphalt. The “bee structure” of asphalt under AFM can scientifically and reasonably explain the microstructural characteristics and evolutionary rules of aging asphalt. These findings can provide a certain theoretical basis for asphalt aging and regeneration technology.