Presentation 4 Numerical Modeling T Weaver 1 Purpose

Presentation 4 Numerical Modeling T. Weaver 1

Purpose of Numerical Modeling l l l Predict E* given aggregate and binder properties Predict pavement performance and assess influence of multiple variables (loads, environment) on behavior Comparative assessment of mix designs 2

Numerical Methods l Discrete Element 3

Numerical Methods l Finite Elements 4

Constitutive Models Hooke’s Law 5

Constitutive Models l Viscoelasticity l Viscoplasticity 6

Constitutive Models l Viscoelastoplastic Parameter Anisotropy, D Viscoelastic stiffness, E 1 Viscoelastic stiffness, E 2 Poisson’s ratio, n Drucker-Prager friction angle, a Drucker-Prager cohesion, �k 0 Perzyna’s viscoplastic parameter, G Perzyna’s viscoplastic parameter, N Dilation Parameter, b Damage Parameter, x 1 Damage Parameter, �x 1 Damage Parameter, x 1 Hardening Parameter, k 2 7

Analyses using Viscoplasticity 8

Analyses with Viscoelastoplastic Model 9

Work Plan l l l Validate proper use of viscoplastic model using ABAQUS Utilize E* test results to determine model parameters for viscoplastic model Develop empirical relation between asphalt pavement properties and viscoplastic model parameters 10

Finite Element Analyses 11

Future Work l Develop specialized FEA code for predicting E* 12