Implementing General Power Law to Interconvert Linear Viscoelastic Functions of Modified Asphalt Binders

Interconversion between the relaxation modulus and creep compliance, which forms a constitutive linear viscoelastic function for asphalt binders, is a classical challenge, even when such a constitutive function is required to be determined at low temperatures based on the bending beam rheometer (BBR) test. Adopting the general power law, a new method was introduced that could precisely fulfill such an interconversion at low temperatures for BBR test data. In order to verify the proposed method, an experimental program was performed on a neat asphalt binder and two modified asphalt binders using crumb rubber and polyphosphoric acid (PPA) individually. Material characteristics were determined from the test data, and they were applied in a numerical framework to simulate BBR test behavior. To ensure the accuracy of using the general power law for interconversion, the results of this approach are compared with well-known approaches introduced by Hopkins and Hamming and Park and Schapery. Numerical results have shown good agreement with the test data. (c) 2018 American Society of Civil Engineers.