Resumen de Uniaxial Nonlinear Viscoelastic Constitutive Model for Asphalt Concrete
Philip Park, ALAN WINEMAN, Sherif El-Tawil
uniaxial, nonlinear, viscoelastic constitutive model for asphalt concrete is proposed. Based on the observation that asphaltic materials exhibit linear viscoelasticity at small strains/stresses and nonlinear behavior at larger strains/stresses, many existing models separately employ linear viscoelastic models for the former regime and plasticity or damage models for the latter. A model is proposed in this paper that deviates from this trend. It assumes that asphalt can be simultaneously characterized by both linear and nonlinear viscoelastic models, each of which dominates during the pertinent mechanical regime. By combining a nonlinear damper with a generalized Maxwell model, the behavior of asphaltic materials in both linear and nonlinear ranges can be simulated with a single set of material parameters to cover a wide range of time, temperature, and stress/strain levels. Numerical integration algorithms for strain controlled loading and a calibration method employing constant strain rate test data are proposed. The model also employs the timetemperature superposition principle and damage mechanics to account for temperature dependency and damage evolution, respectively. Application of the model to asphalt concrete is demonstrated using experimental data from disparate researchers. It is shown that the proposed constitutive model is capable of successfully simulating constant strain rate tests at various temperatures.
Key Words: Nonlinear viscoelasticity, constitutive model, asphalt concrete, mechanical analog, numerical integration 1PhD Candidate, Department of Civil and Environmental Eng., University of Michigan, Ann Arbor, MI 2Professor, Department of Mechanical Eng., University of Michigan, Ann Arbor, MI 3Professor, Department of Civil and Environmental Eng., University of Michigan, Ann Arbor, MI This paper is for publication only
