Laboratory and Accelerated Field Performance Testing of Moderate and HighRAP Content Mixes at NCAT Test Track.

This paper describes the performance of test sections containing moderateand high levels of RAP at the NCAT test track. The test sections includetwo sections with 20% RAP, four sections with 45% RAP, and a control section with no RAP. Each mixture contained the same component aggregates andRAP. One of the 20% RAP mixes contained PG 67-22 binder and the other contained PG 76-22 binder. Different binders were also used in the 45% RAP mixes including PG 52-28, PG 67-22, PG 76-22, and PG 76-22 plus 1.5% Sasobit. All sections are performing well with regard to rutting except the 20%RAP section with PG 67-22 which has 13.0 mm of rutting. Low severity longitudinal wheelpath cracking has been documented in two sections. The 45%RAP section with PG 76-22+Sasobit has a moderate amount of cracking. The20% RAP section with PG 76-22 has a lesser amount of cracking. Other sections have no cracking. Laboratory tests included Asphalt Pavement Analyzer(APA) rutting tests, dynamic modulus, bending beam fatigue, and energy ratio. The APA results were variable and did not correspond to the field performance. Master curves of dynamic moduli show the effects of the virginbinder grade on the stiffness of the mixtures. Beam fatigue tests indicated that the 45% RAP mixes have lower fatigue lives compared to the other mixes. However, the beam fatigue results do not match well with test trackperformance. Likewise, the energy ratio results do not agree with the field performance of the RAP experiment.