Effects of aging behavior on macro and micro characterizations of surfactant–crumb rubber asphalt binders

Abstract

Asphalt aging process degenerates the performance and shortens the lifetime of the pavement, while using warm mix additive and crumb rubber modifier can improve the main negative distress. In this study, aged crumb rubber modified asphalt binder (CRMAB) with and without surfactant (0.6% SK) additive were designed through rolling thin film oven and pressure aging vessel test. The dynamic shear rheometer, bending-beam rheometer, fourier transform infrared spectroscopy, and atomic force microscopy tests were conducted to identify the effects of aging behavior on the macro-rheological properties, chemical constituents, and morphological characteristics of CRMAB and surfactant–crumb rubber modified asphalt binder (S-CRMAB). The findings from micro and macro analysis showed that aging increases carbonyl, sulfoxide, and aliphatic components, decreases aliphatic branched components, causing higher high-temperature rheology, lower low-temperaturen and fatigue performance. However, SK improves its aging resistance and relaxation ability. Moreover, the appearance of uniform hills–valleys and “round and bright lamellar” structures on the surface of 3D and 2D topographic images of S-CRMAB, respectively, indicating the surface roughness decreases, and microstructural stability gets enhanced.