Evolution of the microstructure of unmodified and polymer modified asphalt binders with aging in an accelerated weathering tester

Ilaria Menapace*, Eyad Masad

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)

Abstract

This paper presents findings on the evolution of the surface microstructure of two asphalt binders, one unmodified and one polymer modified, directly exposed to aging agents with increasing durations. The aging is performed using an accelerated weathering tester, where ultraviolet radiation, oxygen and an increased temperature are applied to the asphalt binder surface. Ultraviolet and dark cycles, which simulated the succession of day and night, alternated during the aging process, and also the temperature varied, which corresponded to typical summer day and night temperatures registered in the state of Qatar. Direct aging of an exposed binder surface is more effective in showing microstructural modifications than previously applied protocols, which involved the heat treatment of binders previously aged with standardized methods. With the new protocol, any molecular rearrangements in the binder surface after aging induced by the heat treatment is prevented. Optical photos show the rippling and degradation of the binder surface due to aging. Microstructure images obtained by means of atomic force microscopy show gradual alteration of the surface due to aging. The original relatively flat microstructure was substituted with a profoundly different microstructure, which significantly protrudes from the surface, and is characterized by various shapes, such as rods, round structures and finally ‘flower’ or ‘leaf’ structures.

Original languageEnglish
Pages (from-to)341-356
Number of pages16
JournalJournal of Microscopy
Volume263
Issue number3
DOIs
Publication statusPublished - 1 Sept 2016
Externally publishedYes

Keywords

  • Aging
  • asphalt binder
  • atomic force microscopy
  • bee-like structures
  • microstructure
  • UV radiation

Fingerprint

Dive into the research topics of 'Evolution of the microstructure of unmodified and polymer modified asphalt binders with aging in an accelerated weathering tester'. Together they form a unique fingerprint.

Cite this