Development of an alternative bitumen rejuvenator consisting of waste oils and Reacted and Activated Rubber (RAR)

Abstract

After a long-term in service on pavement, bituminous material exposure to environmental conditions and traffic loads leads to inevitable aging, causing an increase in binder viscosity and making it stiffer. On the other hand, the absence of proper elimination and illegal dumping of waste oil and tire rubber can lead to serious environmental risks. This research aims to investigate the possibility of using waste engine oil (WEO) and waste cooking oil (WCO) separately combined with reactive and activated rubber (RAR) as new alternative rejuvenating agents. In this study, 5% of waste oil (WCO, WEO) and 15% of RAR were added to the aged bitumen with a penetration grade of 20/30. The virgin, aged, and rejuvenated bitumen were investigated for their physical and chemical properties using penetration, softening point, and Fourier transform infrared spectroscopy (FTIR) tests, as well as the effect of thermal cycles (heating and cooling) on the cracking resistance of bituminous mixtures containing regeneration bitumen using the Fénix test. The study outcome indicated that these rejuvenators could effectively soften and restore the basic properties of the aged bitumen to a normal level of 40/50. Meanwhile, the bituminous mixture with the aged bitumen rejuvenated with both oils and tire rubber (AB-WRCO and AB-WREO) showed the best cracking behavior. Therefore, these alternative solutions involve not only reusing the aged bitumen but also reusing the waste oil and tire rubber in order to attain environmental protection and economic benefits.