Modelling the performance of asphalt concrete using continuum damage theories is an approach that has gained international attention in recent years. These types of models are advantageous because they ignore many of the complicated physical interactions at the microscale level and instead characterise a material using macroscale observations. One such model, the viscoelastic continuum damage model, is used in this study to examine the fatigue performance of asphalt concrete mixtures. A mathematically rigorous exploration is undertaken to specialise the model for easy prediction and characterisation using cyclic fatigue tests on cylindrical specimens. This process reveals that certain theoretical shortcomings are evident in other similar models and corrects them with a newly developed model. The resulting model is capable of capturing the underlying material property, i.e. the damage characteristic curve, which is responsible for the performance of controlled stress, controlled crosshead strain and consta...

Improved calculation method of damage parameter in viscoelastic continuum damage model

A thermo-viscoelastic-viscoplastic-viscodamage constitutive model for asphaltic materials

Cracking in asphalt concrete pavements is a major form of pavement distress in the United States. Because the cracking phenomenon is complex and cracking is often affected by both material and structural factors, field engineers have no quick and effective test and analysis protocols. A suite of fatigue analysis tools—as well as applications built around the simplified viscoelastic continuum damage (S-VECD) model—is presented. The S-VECD formulation is presented in a summarized form. Next, the characterization protocols, which are consistent with the capabilities of the asphalt mixture performance tester, are shown. Considerable attention is then given to S-VECD-based analysis tools for assessment of material- and pavement-level fatigue performance. Results show that the S-VECD model can be used to predict the number of cycles until fatigue failure for both constant stress and constant strain loading. The S-VECD model's sensitivity to mixture composition and external factors is shown through predictions o...

Simplified Viscoelastic Continuum Damage Model as Platform for Asphalt Concrete Fatigue Analysis

In the study reported in this paper, the previously developed failure criterion for the viscoelastic continuum damage (VECD) model (referred to here as GRO, where O indicates old and GR is the rate of release of the pseudostrain energy) was applied to different modes of fatigue loading. The research team found that this criterion was mode-of-loading dependent and therefore considered insufficient. To mitigate this limitation, the GRO criterion was refined to become a new failure criterion, the GR method, which resolved the mode-of-load dependency issue. A characteristic relationship, which was found to exist in recycled asphalt pavement (RAP) and non-RAP mixtures between the rate of change of the averaged released pseudostrain energy during fatigue testing and the final fatigue life was derived in this study. This relationship is independent of mode of loading, strain amplitude, and temperature. The proposed failure criterion combines the advantages of the VECD model and this characteristic relationship, ...

Robert Kluttz

Papers

Characterization and performance prediction of ALF mixtures using a viscoelastoplastic continuum damage model

Selection of binder performance indicators for asphalt rutting based on triaxial and wheel tracking tests

Mechanistic modeling of permanent deformation in asphalt mixes with the effect of aggregate characteristics