Properties and mechanism of Re-refined engine oil bottom rejuvenated aged asphalt

Abstract

• 1. Re-refined engine oil bottom (REOB) is similar in composition to asphalt and contains more light components. • 2. The REOB can recover the physical and rheological properties of the aged asphalt. • 3. The REOB can restore the generic fractions and functional groups of the aged asphalt. • 4. REOB-1 has higher content of aromatics and higher permeability into aged asphalt of REOB-1 than those of REOB-2. The asphalts with different aging degrees (mildly, moderately and severely aging) were obtained by indoor aging test to estimate the rejuvenated effect of Re-refined engine oil bottom (REOB) on properties of asphalt with different aging extent. Two kinds of REOB (REOB-1 and REOB-2) with different contents were added into three aging asphalts respectively by melt blending method. The influences of different REOBs on the physical and rheological properties of asphalt with different aging degrees were studied. The thin-layer chromatography with flame ionization detection (TLC-FID), the Fourier transform infrared spectrometer (FTIR) and the permeability test were conducted to analyze the rejuvenated mechanism of REOB on properties of aged asphalt from the points of generic fractions, functional groups and diffusing ability. Results show that the REOB can partly recover the properties of aged asphalt, and the appropriate content of REOB is recommended to be around 15 wt%. Compared between the two REOBs, the REOB-1 has better rejuvenation effect on the aged asphalt than the REOB-2, which can be ascribed to higher content of aromatics and higher permeability into aged asphalt of REOB-1 than those of REOB-2.