Improving the Sustainability of Asphalt Pavements through Developing a Predictive Model with Fundamental Material Properties
Rashid K. Abu Al-Rub, Eyad A. Masad, and Chien-Wei Huang, Texas A&M University, August 2009, 59 pp. (476660-00007-1)
This study presents the numerical implementation and validation of general constitutive relationships for describing the nonlinear behavior of asphalt concrete mixes. These constitutive relationships incorporate nonlinear viscoelasticity and viscoplasticity to predict the recoverable and irrecoverable responses, respectively. The nonlinear viscoelastic deformation is modeled using Schapery’s model; while the irrecoverable component is represented using Perzyna’s viscoplasticity theory with an extended Drucker-Prager yield surface and plastic potential that is modified to capture the distinction between the compressive and extension behavior of asphalt mixes. The nonlinear viscoelastic and viscoplastic model is represented in a numerical formulation and implemented in a finite element (FE) code using a recursive-iterative algorithm for nonlinear viscoelasticity and the radial return algorithm for viscoplasticity. Then, the model is used to analyze the nonlinear viscoelastic and viscoplastic behavior of asphalt mixtures subjected to single creep recovery tests at different stress levels and temperatures. This experimental analysis includes the separation of the viscoelastic and viscoplastic strain components. Based on this separation, a systematic procedure is presented for the identification of the material parameters associated with the nonlinear viscoelastic and viscoplastic constitutive equations. Finally, the model is applied and verified against a set of creep-recovery tests on hot mix asphalt at different stress levels and temperatures.
Keywords: Mechanistic Model; Viscoelasticity; Viscoplasticity; Damage Mechanics; Hot Mix Asphalt; Finite Element; Creep-Recovery
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