Impact of High RAP Content on the Performance Characteristics of Asphalt Mixtures in Manitoba

摘要

Pavement sections with 15% RAP, 50% RAP with and without virgin binder grade change, and a conventional hot-mix without RAP were built side-by-side in 2009 on Provincial Trunk Highway 8 from Gimli to Hnausa in Manitoba, Canada. During construction, field-produced mixtures and raw materials were sampled for further evaluation. The raw materials were used to reproduce the various mixtures in the laboratory. This paper presents the results of an extensive laboratory evaluation of the field- and laboratory-produced mixtures to moisture damage and thermal cracking resistance. The moisture damage was evaluated using the dynamic modulus test at multiple freeze-thaw cycles. The thermal cracking resistance of the mixtures was also evaluated at multiple freeze-thaw cycles using the thermal stress restrained specimen test (TSRST). Overall, HMA mixtures with 50% RAP resulted in acceptable resistance to moisture damage and thermal cracking. The use of multiple freeze-thaw cycles provided better indication of the mixture resistance to moisture damage. Overall, the properties of the laboratory-produced mixtures in terms of moisture damage and thermal cracking resistance can be used to ensure quality field-produced mixtures.