This study will address several questions about the long-term properties of asphalt binders and their impact on pavement performance. It will consider the influence of recycled asphalt pavement (RAP) through the following questions:

• How does RAP content influence binder grade and mixture performance?
• How do binder grades change over time? 
• Is this influenced by the presence of RAP?
• How does the depth within the surface layer affect binder aging?
• Is there a relationship between deterioration and in-service binder grade?

The project will examine a sample of in-service pavements of different ages and constructed with varying binders and RAP contents. These include trial sections evaluated during construction in 2007 in a study by Maupin et al. (2008).  It also will include projects using RAP contents above 30 percent. Mixture and binder properties will be compared to original construction data and correlated to performance to assess the changes in the mixture during service.