The performance of asphalt mixtures is significantly affected by the viscoelastic properties of their mastic phase. The analytical approaches used to predict the properties of mastics from their constituents’ properties are limited in their accuracy and potential to handle non-linear material behaviour. An alternative micromechanical finite element modelling approach to calculate the master curves of mastics from the binder and filler phase properties is presented, where the representative volume elements of mastics consist of linear-viscoelastic bitumen matrices and elastic spherical filler particles. For validation, shear relaxation moduli of bitumen and bitumen-filler mastics are measured at (Formula presented.) °C (Formula presented.) °C. Additionally, the model is evaluated and compared with the existing analytical solutions. The results indicate that the proposed approach is advantageous as compared to the analytical solutions, as it allows predicting the mastics’ properties over wider temperature, frequency and material ranges at better agreement with the measurements while giving insight into the micromechanical behaviour.