Rejuvenation of aged asphalt binder extracted from reclaimed asphalt pavement using waste vegetable and engine oils

After many years in service, bituminous material in roads becomes aged and starts losing its properties. Aged bitumen becomes more brittle and causes a reduction in pavement strength with a decrease in the service life of pavement. The dumping activity of untreated waste oils into landfills or rivers causes negative effect towards an environmental aspect. The objective of this study is to investigate the possibility of using waste oils; waste vegetable oils (WVO) and waste engine oils (WEO), as rejuvenating agents for aged asphalt binder extracted from reclaimed asphalt pavement (RAP). In this study three percentages (1%, 2% and 3%) of both WVO and WEO were added to 20/30 penetration grade aged asphalt. Physical and chemical properties of aged and rejuvenated asphalt binders were investigated using different laboratory tests and evaluated according to general specifications of roads and bridges in Iraq. The results indicated that both of WVO and WEO could effectively soften and rejuvenate the aged asphalt where 1% of WVO and 3% of WEO could restore the aged (20/30) asphalt to its original (40/50) penetration grade. Furthermore, viscosity, temperature susceptibility and aging resistance of rejuvenated asphalt were improved compared to the original asphalt binder. The asphaltenes content decreased as a result of reducing the intensity of carbonyl and sulfoxide of aged asphalt due to the addition of waste oils. Moreover, it could be noted from the results that more concentration of WEO needed to regenerate the aged asphalt compared to WVO. Finally, it can be concluded that rejuvenation of aged asphalt using WVO and WEO is feasible and can be considered as an effective way to recycle both of RAP and waste oils. (C) 2019 The Authors. Published by Elsevier Ltd.