Fatigue Evaluation of Warm-Mix Asphalt Mixtures: Use of Uniaxial, Cyclic, Direct Tension Compression Test

Warm-mix asphalt (WMA) is the generic term used to refer to a group of technologies that are used to produce asphalt pavement mixtures at temperatures lower than those of traditional hot-mix asphalt (HMA). One of the potential benefits of WMA is that it provides better fatigue cracking characteristics than does HMA. The lower temperatures should reduce the aging of asphalt binders that occur during production. The reduced aging of asphalt binders should lead to improved fatigue characteristics of asphalt mixtures. The research reported here addressed two main objectives. The first was to study the impacts of three WMA technologies on the fatigue cracking resistance of HMA by using one asphalt binder and two aggregate sources. The fatigue characteristics were measured by using a uniaxial, cyclic, direct tension compression test. The second objective was to analyze the data produced by the test by using the simplified viscoelastic continuum damage approach proposed in the NCHRP 9–43 Phase I report. Three WMA technologies were used: Advera, Evotherm 3G, and Sasobit. All mixtures were produced by using a PG 64-22 virgin binder. Data showed no significant difference between HMA mixtures and WMA mixtures for each mix except for the Advera.