Study on Characteristics and Evaluation of the Fusion Behavior Between New and Aged Asphalt Interface

To quantitatively study the fusion behavior of new and aged asphalt interface with multiple factors, this paper used dynamic shear rheometer, Fourier-transform infrared spectrometry, gel permeation chromatography, and atomic force microscopy to investigate the effects of time, temperature, and rejuvenator on the fusion process of the new and aged asphalt interfaces from both macroscopic and microscopic aspects. The macroscopic fusion behavior of new and aged asphalt was characterized by diffusion rate, fusion degree, and diffusion activation energy; the microstructure was characterized by carboxyl index(I (S=O) ), sulfoxide index (I (C=O) ), large molecular size (LMS), and roughness indexes. Macroscopic results showed higher temperature, longer time, and the addition of rejuvenator are beneficial for new and aged asphalt fusion degree. The microscopic study showed that with the fusion of new–old asphalt, the molecular content of aged asphalt on the new asphalt side increased, its I (C=O) and I (S=O) increased, the LMS increased, and the roughness increased. Meanwhile, each microstructural index was analyzed with the characterization indexes of macro fusion behavior, and the macro and micro indexes correlated well.