Thermo-oxidative aging of bitumen

Thermo-oxidative bitumen aging has been commonly recognised as the main cause of asphalt cracking. The effect of thermo-oxidative aging level on bitumen has been studied in this work by means of a simple and effective mechanical stirring process. Physical characteristics of the material, such as Softening Point, Penetration and Viscosity, were measured on samples with different aging conditions. Chemical changes in the material were evaluated by means of SARA fractioning to measure the effect of aging on the fundamental components of bitumen, and Infrared Spectroscopy in order to study the changes found in the oxidation-related compounds of the material. Microstructural changes in the material were evaluated using atomic force microscopy (AFM) finding that the aging process on bitumen increases the number and size of the phases related to asphaltenes and resins, and decreases the amount of phases related to aromatics. The changes in chemical and physical characteristics of bitumen were found to be strongly dependent on the carbonyl formation. An extension to a previously proposed oxidation kinetics model was used to predict the fast rate (transient) and constant rate (steady-state) oxidation behaviour of bitumen and its relation to physical properties. The thermo-oxidative changes suffered by bitumen are associated with increasing hardening of the material, making it susceptible to cracking when in contact with aggregate as thin films in flexible pavements.


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  • Accession Number: 01669495
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 21 2018 11:38AM