Improved understanding of rutting resistance of a rubberized asphalt concrete pavement that contains reclaimed asphalt pavement (RAP) is important to stimulating the use of rubberized asphalt mixtures. Use of RAP in the past has proved to be economical, environmentally sound, and effective in increasing the rutting resistance of asphalt mixtures. Rubberized asphalt has been used successfully in improving the mechanical characteristics, such as rutting resistance, of typical hot mix asphalt (HMA) mixture around the country and the world. The objective of this research was to investigate the rutting resistance characteristics of the rubberized asphalt mixtures through a laboratory testing program. The experimental design included use of two rubber types (ambient and cryogenically produced), four rubber contents, and three crumb rubber sizes. The results of the experiments indicated that the use of RAP and crumb rubber in the HMA can effectively improve the rut resistance of these mixes.

Rejuvenator is not a commonly used softening agent to be used in recycling of reclaimed asphalt pavement (RAP). In this study, Superpave mixtures containing RAP were designed using rejuvenating agents, including a rejuvenator and a softer binder, and subsequently evaluated in terms of the volumetric results, obtained the indirect tensile strength (ITS) of samples as well as evaluating the mixtures for rutting using the asphalt pavement analyzer (APA). The content of the rejuvenator used for those mixtures containing the rejuvenator was determined from the blending charts of RAP binders containing the rejuvenator. A total of 12 Superpave mixtures including 10 containing RAP and two virgin were designed. The results indicated, for the mixtures tested for this project, that: (1) properties of the recycled mixtures using the rejuvenator, such as ITS and APA, were better than those containing the softer binder; (2) 10% more RAP could be incorporated in the Superpave mixtures by using the rejuvenator than using...