On using micromechanical models to describe dynamic mechanical behavior of asphalt mastics

The applicability of micromechanical models in describing the dynamic mechanical behavior of asphalt mastics is explored. The complex sets of equations from the "generalized self-consistent scheme" (GSCS) are simplified using an order of magnitude analysis. The simplification provides a better perspective and insight into how the model operates and predicts. For asphalt mastics, it is found that the stiffness ratio is sensitive only to the Poisson's ratio of the binder and the volume fraction of the fine aggregates. The results from the model when compared with experimental data indicate that the theoretical predictions fall short of the experimental values. This is because the GSCS model in its original complex form as well as in the simplified form is unable to capture the effects of all the variables involved in the increase of the stiffness ratio of the mastics. The concepts of percolation theory are incorporated to obtain a modified form of the model. This modified model fits the experimental data of asphalt mastics well when appropriate values of two adjustable parameters, namely, the volume fraction at percolation threshold and the maximum volume fraction of the filler are used. (C) 2002 Elsevier Science Ltd. All rights reserved.