Authors:
Nahid Amini; Hassan Latifi; Parham Hayati;
Abstract:
Here, the aging behavior of asphalt was evaluated by investigation of the changes of rheological, chemical, physical, microstructural and macrostructural properties of pure and well-dispersed Nano-CuO, multiwall carbon nanotube; MWCNT and SBS-modified asphalt binders. Firstly, rotating thin-film oven and pressurized aging vessel experiments were conducted to prepare short- and long-term aging samples, respectively. In the following, rotational viscosity (RV), dynamic shear rheometry (DSR), Fourier transform infra-red (FTIR),
scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were carried out. RV and DSR analyses showed that modified asphalt binders had more viscosity and aging resistance than pure ones. FTIR spectra indicated a decrease of sulfur and oxygen, in the form of sulfoxide and carbonyl, respectively, especially in the Nano-CuO-modified asphalt binder. Besides, chemical reactions in the modified-asphalt binders enhanced the oxidation and thermal resistances. XRD pattern illustrated a direct relationship between the aging of the asphalt binder and the crystallinity of the studied asphalt binders. Also, Nano-CuO-modified and Nano-CuO-SBS-modified asphalt binders were chemically more uniform and homogeneous than other samples. Moreover, the calculated aging index (AI), G*×sin(δ) and FTIR & XRD patterns accurately confirmed each other.
Keywords:
Asphalt aging, XRD, Nano-CuO, Oxidation, FTIR, Carbonyl.