Evaluation of Binder Aging and Its Influence in Aging of Hot Mix Asphalt Concrete: Literature Review and Experimental Design (0-6009-1)

Binder oxidation in pavements and its impact on pavement performance has been addressed by numerous laboratory studies of binder oxidation chemistry, reaction kinetics, and hardening and its impact on mixture fatigue. Studies also have included some work on binder oxidation and hardening in pavements and the effectiveness of maintenance treatments. Yet more such studies are needed to better understand the fundamentals of pavement performance as a function of climate and pavement parameters. Based on these reports in the literature, an experimental design has been developed to meet three objectives and to provide four products. The objectives are: 1) to develop and calibrate a laboratory test to assess binder aging during the production process and during the field service of the pavement; 2) to incorporate aging for use in a HMA mix design system to produce mixtures that provide adequate resistance to fatigue cracking, including guidelines to optimize resistance of HMA to aging; and 3) to evaluate the use of maintenance treatments to reduce the aging of asphalt pavements starting at early ages. The products: 1) a new test procedure to characterize binder aging, and predict service life for different applications; 2) an HMA mix design component that incorporates aging and its effect on resistance to fatigue cracking; 3) guidelines for optimizing HMA mixture resistance to aging; and 4) guidelines for the best maintenance treatments to reduce the aging of binders. The experimental design includes measurements of binder oxidation and hardening at various stages of binder service, fundamental studies of binder oxidation and hardening kinetics, developing a transport model of binder oxidation in pavements, measurements of field oxidation and hardening rates, measurements of mixture fatigue decline as a function of binder oxidative hardening in both the field and laboratory, and measurements of maintenance treatment effectiveness at retarding binder oxidative hardening.