INVESTIGATION OF IMPACTS OF CASTOR OIL AS A REJUVENATOR ON RECYCLED ASPHALT PAVEMENT

Abstract

The use of recycled asphalt pavement in road construction sector is limited due to its poor cracking performance. Application of rejuvenator is an emerging solution for regaining the lost properties of RAP. Prior research mainly deals with chemical rejuvenators which are unsustainable and sometimes carcinogenic. The usage of oil-based organic rejuvenators causes higher softening effects on pavement and thereby reduce the load carrying capacity. This study deals with this gap by evaluating the impacts of castor oil as a rejuvenator on the performance of binder and mixtures containing 30% and 60% RAP materials. The physical and rheological properties of binder were studied by conventional tests and dynamic shear rheometer test respectively. The volumetric properties of mixtures were evaluated by Marshall, Indirect tensile strength test and Self-healing capacity test. The findings revealed that, the physical properties could regain with the addition of 5% and 8% castor oil to the RAP binder. The rutting parameter of both rejuvenated RAP binder with optimum castor oil were higher than that of virgin binder while the fatigue parameter was reduced that of virgin binder. This ensure that the rheological parameters could enhances by the addition of castor oil. The mechanical properties and self-healing capacity of rejuvenated RAP mixtures were enhanced in comparison to the control mixture. In summary, the usage of RAP with optimum castor oil in mixtures show promising outcomes and there by ensure the sustainable development practices in the future.