Four-component united-atom model of bitumen

Journal of Chemical Physics/ Volume 138/ Issue 9 (2013)
Four-component united-atom model of bitumen
J. S. Hansen 1, Claire A. Lemarchand 1, Erik Nielsen 2, Jeppe C. Dyre 1, and Thomas Schrøder 1
1 DNRF Centre “Glass and Time”, IMFUFA, Department of Science, Systems and Models, Roskilde University, Postbox 260, DK-4000 Roskilde, Denmark
2 Danish Road Directorate, Guldalderen 12, DK-2640 Hedehusene, Denmark
Abstract
Authors present a four-component united-atom molecular model of bitumen. Their model includes realistic chemical constituents and introduces a coarse graining level suppressing the highest frequency modes. They conducted molecular dynamics simulations of the model using graphic-processor-units based software in microsecond time spans, enabling the study of slow relaxation processes characterizing bitumen.
In addition, they present results of the model dynamics as expressed through the mean-square displacement, the stress autocorrelation function, and rotational relaxation. Their model demonstrate that the asphaltene, resin, and resinous oil tend to form nano-aggregates. The characteristic dynamical relaxation time of these aggregates is larger than that of the homogeneously distributed parts of the system, leading to strong dynamical heterogeneity.
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