ABSTRACT
Recently, a significant increase in the use of Recycled Asphalt Pavement (RAP) in the United States (US) has been observed. In 2014, more than 70 million tons of RAP material was used in new pavements making RAP one of, if not the largest, recycled materials in the US. Old and aged RAP material is known to have an asphalt binder that is stiffer and more brittle than virgin asphalt binders typically used in asphalt mixtures. While the use of RAP in an asphalt mixture is expected to improve the mixture’s resistance to rutting, it has a great tendency to reduce the mixture’s resistance to cracking especially at the significantly high amount of RAP (more than 30%). In this pilot study, a new polymer binder called TechniSoil G5® was evaluated for use with a 100% RAP material. An extensive laboratory evaluation of the mechanical and mechanistic performance of the stabilized 100% RAP mixture was conducted. The designed mixture was evaluated in terms of its dynamic modulus property, resistance to rutting, and resistance to fatigue and thermal cracking. A mechanistic analysis was also conducted to determine the fatigue life of the stabilized 100% RAP mixture when used in a typical pavement structure at two different vehicle speeds using the 3D-Move Analysis software. The data showed that the stabilized 100% RAP with TechniSoil G5® has excellent resistance to the evaluated and critical asphalt pavement distresses. A significant increase in the fatigue life was also observed when compared to a typical dense-graded asphalt mixture. Based on the promising laboratory results, a field demonstration project was constructed in 2016 at the Al Wakar water station in Doha, Qatar. Initial field inspection six months after construction showed that the pavement with G5®-stabilized RAP mixture is performing very well under the hot desert environment.
