Method for Performing Accelerated Characterization of Viscoelastic Constitutive Behavior of Asphaltic Concrete

Abstract

Constitutive models based in continuum mechanics are formulated for modeling the time dependent mechanical response of asphaltic concrete. The model chosen for the initial phase of study is linear viscoelastic, resulting in stress-strain relations that are of the single integral Boltzmann type in time. Experimental equipment and testing protocols are described for obtaining material properties within the viscoelastic framework selected for characterization. A frequency sweep experimental technique is described for obtaining composite properties from short-term tests that can be used to predict long-term, time-dependent material behavior. Mathematical techniques are described for converting experimentally obtained complex compliances to creep compliances and relaxation moduli in the time domain. These techniques are then used to produce the relaxation moduli for four different mixes of asphaltic pavement.