Novel Methodology to Investigate and Obtain a Complete Blending between RAP and Virgin Materials

Abstract

Pavement engineers are continually attempting to resolve the problems associated with disposal of highway construction materials and conserve the natural resources in line with producing a more economically and environmentally friendly asphalt mixture. This study presents a novel methodology to investigate and obtain a complete blending in the laboratory using nano-mechanical approach so that designers can be more confident in estimating the performance of asphalt mixtures incorporating RAP materials. The study also presents an effect of warm additives, Sasobit and Rediset LQ on the level of blending between RAP and virgin materials. Images obtained from nanoindentation were validated using scanning electron microscopy (SEM) while level of blending was linked to the overall fatigue-cracking of asphalt mixtures which were measured using Dynamic shear rhemoter (DSR). It was revealed that although Rediset LQ improved the fatigue life and nano- mechanical properties of virgin interfacial transition zone (ITZ) and mastic phases, it has no effect on the diffusion of virgin binder into aged binder (binder surrounding RAP aggregate) or rejuvenating of aged binder while as Sasobit decreased the viscosity of binder, it has a great influence in accelerating complete blending between RAP and virgin materials. In summary, nanoindentation integrated with an optical microscopy is a powerful technique to investigate and obtain complete blending between RAP and virgin materials.