Enhanced sustainability at the bitumen-aggregate interface using organosilane coating technology

Sand Aldagari, Albert M. Hung, Saba Shariati, S. K. Faisal Kabir, Mikhil Ranka, Richard C. Bird, Elham H. Fini

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


This paper uses molecular modeling and laboratory experiments to investigate the merits of an organosilane modifier to enhance resistance to moisture at the bitumen-aggregate interface. The organosilane modifier (referred to as OS1 in this study) forms a coating layer on stone aggregates, bridging between the aggregates and the bitumen molecules. Measurements of the moisture–induced shear-thinning index found the best moisture resistance for a sample with an optimum dosage of 0.6 % OS1 cured at 150 °C for 60 min. The performance of the bitumen modified by the optimum dosage of OS1 was not reduced after being exposed to short-term aging and long-term aging, indicating low susceptibility to thermal and oxidative degradation. For glass beads with the optimum OS1 coating, contact-angle measurements showed notable hydrothermal stability after hydrolysis. However, using an amount of OS1 greater than 0.6 % increased bitumen's susceptibility to moisture damage; thick layers of OS1 were unstable when exposed to hydrolytic treatment. Molecular modeling showed excess OS1 forming thick multiple layers on the silicate substrates; these layers had poor bonding to the first adsorbed OS1 layer, allowing water infiltration into the system. Surprisingly, dry surface adhesion (to bitumen) of an OS1-coated glass bead was nominally less than that of UV–ozone-cleaned glass. The study outcomes highlight the importance of optimizing factors to maximize the effectiveness of a modifier in bituminous composites.

Original languageEnglish (US)
Article number129500
JournalConstruction and Building Materials
StatePublished - Dec 12 2022
Externally publishedYes


  • Adhesion
  • Adsorption
  • Aged bitumen
  • Bitumen
  • Durability
  • Moisture damage
  • Organosilane
  • Silica surface
  • Tack coat

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Materials Science(all)


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