(145b) Rheological Study of Asphalt Using Molecular Simulation and Signal Processing

Asphalt is an amorphous material whose mechanical performance relies on viscoelastic responses to applied strain or stress. High quality pavement can enhance the commute experience and also can reduce the risk of accidents as well as preventing air pollution. Furthermore, it also can reduce the need for expensive reconstruction and maintenance of roads.
Having a broad understanding of asphalt chemistry is the key to understand and improve mechanical properties of this material. Chemical composition and its effect on the viscoelastic properties of model asphalts have been investigated by computing complex modulus from molecular dynamics simulation results for two different model asphalts (ZG08 and LG14) whose compositions each resemble the Strategic Highway Research Program AAA-1 asphalt in different ways.
Complex moduli at different temperatures have been calculated using fast Fourier transform to study the effect of temperature on viscoelastic properties of asphalt models. Because of inherent noise, any comparison was almost impossible. To remove the noise, signal processing techniques have been exploited. Signal processing techniques enhanced the clarity of the results and removed the noise from our results. LG14 have shown a very good agreement with the low and high frequency scaling limits of the Maxwell model within the frequency ranges spanned by the molecular dynamics simulations, while the ZG08 model asphalt only follow the high frequency scaling limits of the Maxwell model.