Abstract
Fatigue cracking of viscoelastic asphalt composite materials is one of the major distresses in asphalt pavements. To quantify the weakening effect of the fatigue cracks on the mechanical properties of the viscoelastic asphalt composite materials, this study takes an asphalt-filler composite system as an example, and micromechanics models are proposed by combining Eshbely’s equivalent inclusion theory and Mori-Tanaka approach. Dynamic shear rheometer (DSR) tests are performed on the viscoelastic asphalt-filler composite systems with two volumetric contents of inclusion (10% and 27%) at different frequencies (0.1–100 Hz), temperatures (15℃, 20℃, 25℃) and strain levels (0.01%-0.1% for nondestructive DSR tests; 5%, 6%, 7% for destructive DSR tests). Results show that the predicted shear modulus results by a modified viscoelastic strengthening coefficient (VSC) model match with the test results at both low and high filler contents. Then a viscoelastic strengthening coefficient with fatigue cracks (VSC-f) model is proved being capable of accurately predicting the shear modulus for the viscoelastic asphalt-filler composite systems at different strain levels, temperatures, filler contents and damage levels. Both the VSC and the VSC-f model are derived to be dependent of loading frequency, temperature and filler content, but independent of strain level.
Highlights
Asphalt materials, such as asphalt mastic, asphalt mortar and asphalt mixture, are widely used in pavement engineering to construct the surface layers of roads, highways, ports, runways and car parks
Under the effect of moving vehicles load, the macroscopic mechanical response of the viscoelastic asphalt composite system in pavement structures is effected by the interaction of the asphalt binder matrix and the various inclusions
These empirical models cannot reveal the interacting mechanism caused by the asphalt binder matrix and the inclusions of the viscoelastic asphalt composite system, which limits the development of these empirical models
Summary
Asphalt materials, such as asphalt mastic, asphalt mortar and asphalt mixture, are widely used in pavement engineering to construct the surface layers of roads, highways, ports, runways and car parks. The mechanical properties of the viscoelastic asphalt composite system are predicted based on the mechanical properties of the asphalt binder matrix and aggregate inclusion in the empirical models [4,5,6]. These empirical models were obtained by statistical regression analysis of test results at specific testing conditions. It is necessary to extend the micromechanics model to the destructive condition such as fatigue crack propagation when studying the macroscopic mechanical properties for viscoelastic asphalt composite materials. A summary section concludes this study with the main results
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