Investigation of physicochemical and rheological properties of SARA components separated from bitumen

Abstract To further understand the aging and regeneration of bitumen at component level, physicochemical and rheological properties of bituminous components were investigated. Saturates, aromatics, resins and asphaltenes (SARA) from two bitumen were separated. They are subsequently used for purity identification by TLC-FID test. Fluorescence microscopy, infrared spectroscopy and dynamic shear rheometer (DSR) were conducted to characterize the fluorescence effect, molecular structures and rheological properties of SARA components. The results indicate that high purity of components were obtained according to the validation of TLC-FID. Maltenes show fluorescent activity in a decreasing order of aromatics, saturates and resins. Conversely asphaltenes show average 99 vol% gray scale, representing their extreme inertia under ultraviolet light. Aromatics are most susceptible to aging among light components in bitumen due to the detection of carbonyl group in it. It is shown that O–H stretching vibration as the characteristics of alcohol and acid only stay in asphaltenes. Maltenes exhibit typical viscoelastic characteristic, in which aromatics behave most likely to their mother bitumen. They attribute mostly to the flexibility of bitumen. Results of complex viscosity and flow activation energy reveal that saturates and aromatics present better fluidity than their mother bitumen.