Resilient Modulus Behavior of Rubberized Asphalt Concrete Mixtures Containing Reclaimed Asphalt Pavement

ABSTRACT The resilient modulus is the modulus to be used with the elastic theory during any analysis of a flexible pavement. It is well known that most paving materials (e.g., asphalt pavements) are not elastic but experience some permanent deformation after each load application. With respect to the complexity of the Rubberized Asphalt Concrete (RAC) containing Reclaimed Asphalt Pavement (RAP), the Indirect Tensile Strength (ITS) and resilient modulus evaluation of modified mixtures are important to understand. The aging of binder containing crumb rubber obviously alters the visco-elastic and plastic characteristics of the modified mixtures. The deformation of the mixture under repeated loading, nearly completely recoverable, should also be considered. The experimental design included the use of two aggregate sources, one rubber type (ambient), four rubber contents (0%, 5%, 10%, and 15%), one crumb rubber size (-40 mesh [-0.425 mm]), and four RAP contents (0%, 15%, 25%, and 30%). The findings indicated that an increase in the rubber content in the modified mixture leads to a decrease in ITS and resilient modulus values regardless of rubber content, and this increase also improves the aging resistance and increases the viscous characteristics of the modified binder. However, as RAP content increased, not only the viscosity and G*sinδ values of the modified binder increased, the ITS and resilient modulus values of the modified mixtures also increased.