Developing Model Asphalt Systems Using Molecular Simulation

Computer based molecular simulations have been used towards developing simple mixture compositions whose physical properties resemble those of real asphalts. First, Monte Carlo simulations with the OPLS all-atom force field were used to predict the density, heat capacity, thermal expansion coefficient, and isothermal compressibility for small molecules similar to compounds found in asphalts. Similar calculations were then performed on a 3-component mixture for which detailed property measurements were available in the literature. Good agreement between simulation predictions and experiment (literature values) was found in all cases. Molecular dynamics simulations were then used to estimate the same properties for two asphalt-like mixtures. Different molecules were chosen to reflect the maltene, resin, asphaltene components of an asphalt, with each mixture based on a different asphaltene structure taken from the literature. Different density, glass transition, and bulk modulus properties were found for the mixtures, indicating the effects of different asphaltene structures. Distributions in molecular orientation between molecules were also calculated, to learn the extent of predicted parallel vs. perpendicular ordering in the mixture. A key finding is that molecules tend to order randomly over 3 nm length scales. A literature review of related asphalt chemistry is included in the report as well.

Language

  • English

Media Info

  • Media Type: Web
  • Edition: Final Report
  • Features: Bibliography; Figures; Tables;
  • Pagination: 110p

Subject/Index Terms

Filing Info

  • Accession Number: 01139763
  • Record Type: Publication
  • Contract Numbers: URI 2301 0000216, 2301 0000259
  • Files: UTC, NTL, TRIS, STATEDOT
  • Created Date: Sep 16 2009 10:33AM