A Laboratory Evaluation of Aging on the Viscoelastic Material Functions of Asphalt Concrete and Its Binder

摘要

This study evaluates changes in viscoelastic properties of asphalt concrete and its binder due to aging. In essence, field collected asphalt mixes were used to prepare cylindrical asphalt concrete specimens using a Superpave gyratory compactor and were subjected to five different aging levels: unaged, Level 1, Level 2, Level 3, and Level 4. Next, the aged samples were tested for viscoelastic material functions such as complex modulus, relaxation modulus, and creep compliance in the laboratory. Using the test data, mastercurves of related viscoelastic material functions were determined. Results show that aging affects these viscoelastic materials functions significantly. In addition, liquid asphalt binders corresponding to the asphalt mixtures were tested for complex shear modulus using dynamic shear rheometer. It is shown that aging affects binder's shear modulus and viscosity significantly. Toward the end, contribution of binder aging to the overall aging of AC is assessed.