The properties of reclaimed asphalt used in road construction by rejuvenating agents

Recycling is the inevitable part of many industries. Reserving and effective use of natural resources is a must for today's human being. Recycling in the asphalt industry is one of the most concerned areas and Reclaimed Asphalt Pavement (RAP) is amongst the most recycled materials in the world. Utilization of RAP in new asphalt pavements may lead to severe quality problems mostly due to asphalt aging phenomenon. Within the scope of this study, the use of rejuvenators to improve the properties of RAP has been investigated. Two different kinds of waste oils together with a commercial rejuvenator were used. The rejuvenated bitumen samples were investigated from rheological, morphological and chemical aspects. In addition, mixture testing was also performed to study the effectiveness of used rejuvenators. Experimental studies on bitumen samples mainly included conventional and Dynamic Shear Rheometer (DSR) testing for rheological studies, Atomic Force Microscopy (AFM) imaging for morphological studies and Fourier Transform Infrared Spectroscopy (FTIR) spectra analysis for chemical studies. Mixture testing consisted of Marshall and Indirect Tensile Test (IDT) investigation. The results unveiled that the utilization of rejuvenators can significantly improve the quality of recycled asphalt. Binder and mixture testing showed high consistency and conformity with each other. The results proved that many oily based materials including waste oils can be used as rejuvenating agents. Rejuvenators can significantly restore the properties of aged RAP bitumen and increase the amount of RAP in bituminous mixtures.