Interpretation of Indirect Tension Test Based on Viscoelasticity

The diametral indirect tension test is a convenient configuration for determining the modulus of asphalt concrete samples. The resilient modulus test has been a traditional approach to characterizing the stiffness of asphalt concrete, but it leaves much to be desired when considering the viscous behavior this material exhibits, even at low temperatures. A method for determining the complex compliance, complex modulus, and phase angle of asphalt mixtures using the indirect tensile test and a haversine load history is presented here. This test may be performed over a range of frequencies and temperatures as demonstrated on materials used in the Minnesota Road Research Project. The use of the haversine loading simplifies the test when compared with the pulse loading and rest time used in the resilient modulus test, and it allows for the characterization of the elastic and viscous components of the material's overall behavior, which is very difficult, at best, with the current test methods.