Influence of asphaltene content on mechanical bitumen behavior: experimental investigation and micromechanical modeling

摘要

The description of the mechanical behavior of bitumen on the basis of its microstructure allows its improvement and moreover the development of equivalent or even more sustainable materials with similar properties. For this reasons, a micromechanical model for bitumen is proposed, allowing the description of the viscoelastic bitumen behavior depending on characteristics of different material phases. The definition and demarcation, respectively, of material phases is based on SARA fractions, and polarity considerations that support the assumption of asphaltene micelle structures within a contiguous matrix and the assumed interactions between them. A sufficient number of static creep tests on artificially composed bitumen samples with asphaltene contents from 0 to 30 wt% served both as identification as well as validation experiments for the developed micromechanical model. An excellent agreement between experimental results and model predictions indicates that the model is able to reproduce significant microstructural effects, such as interactions between asphaltenes, which strongly influence the bitumen behavior. This model is therefore expected to contribute to a better understanding of the influence of the bitumen microstructure on the macroscopic mechanical behavior and subsequently be able to describe the mechanical consequences of microstructural effects like aging.