Continuum Damage Approach to Asphalt Concrete Fatigue Modeling

Didier Bodin,Jean-Michel Piau,Armelle Chabot,Gilles Pijaudier-Cabot,Chantal De La Roche

doi:10.1061/(asce)0733-9399(2004)130:6(700)

Abstract

A nonlocal damage model is proposed to predict the behavior of pavement fatigue cracking. This constitutive relation has been implemented in a finite-element code, along with a self-adaptive jump-in-cycle procedure for high cycle fatigue computations. Strain localization analysis shows that during uniaxial fatigue tests, bifurcation due to strain softening occurs much later than in monotonic tests. The incorporation of an internal length into the constitutive model is advocated since the model should encompass loading histories with very different amplitudes of cycles, in which localization may still occur. The influence of the internal length on the fatigue life of bending beams is also investigated. Calibration of the damage model is performed after thermal effects have been evaluated and accounted for in a simplified way, uncoupled to damage. Parameter identification is performed in bending and uniaxial tests. The resulting calibrated constitutive relation is found to yield a good description of several different uniaxial tests.

Highlights

Repeated stress and strain induced by traffic loads can be very damaging to asphalt pavements
In the French design method, the principle is to compare the strain level calculated at the bottom of the asphalt layer to admissible strain, which is strain leading to failure for 1 million cycles during a standardized fatigue test, modified by a shift factor that takes into account in situ conditions that are more complex than in laboratory test conditionshealing, temperature, frequency, etc.͒
The present constitutive relation has three parameters involved in evolution law for damage, in addition to the elastic constants and internal length that are in the nonlocal equivalent strain

Summary

Introduction

Repeated stress and strain induced by traffic loads can be very damaging to asphalt pavements. The present constitutive relation has three parameters involved in evolution law for damage, in addition to the elastic constants and internal length that are in the nonlocal equivalent strain.

Results

Conclusion