Evaluation of the relationship between the fatigue performance of FAM and AC mixtures based on volumetric characteristics and on the S-VECD theory

Abstract

This study investigates the fatigue performance behavior of Asphalt Concrete (AC) mixtures and their corresponding Fine Aggregate Matrix (FAM) mixtures based on the simplified viscoelastic continuum damage (S-VECD) mechanics theory. For that, uniaxial loading tests were performed for the linear viscoelastic and the fatigue characterization of AC and FAM mixtures and also for the construction of the damage characteristic curves (C vs. S), from which the failure criterion parameter, GR, was determined. Then, the fatigue factor of the mixture (FFM) was determined for strains of 100 µε and 200 µε, which are typical critical values observed at the bottom part of asphalt concrete layers in the field. Three fundamentally different approaches were employed to compare the strains of FAMs that resulted in an equivalent fatigue life for the corresponding ACs by the determination of a FAM/AC strain ratio. The results showed that the mixture with the lowest amount of FAM presented the highest strain ratio. The relationship between the FAM/AC strain ratio and the FAM content present in the AC was identified as a key material characteristic that needs to be carefully determined to optimize the AC volumetric and mechanical properties. The deeper understanding of that relationship may facilitate the development and application of advanced multiscale models that attempt to predict the cumbersome behavior of the AC composites based on the inner characteristics and interactions among their constituents.