Binder oxidative aging in Texas pavements: Hardening rates, hardening susceptibilities, and impact of pavement depth

Nasser A. Al-Azri*, Sung Hoon Jung, Kevin M. Lunsford, Ann Ferry, Jerry A. Bullin, Richard R. Davison, Charles J. Glover

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

46 Citations (Scopus)


Aging of binders in pavements is much less understood than laboratory aging of neat binders because of a number of complications. Complications include suitable extraction and recovery methods; uncontrolled variables and unknowns such as mixture characteristics (e.g., air voids), maintenance treatments, traffic, and climate; sustaining of a research effort to study a given pavement during an appropriate time frame (in excess of one decade); and cost. An ongoing research effort sponsored by the Texas Department of Transportation studied binder oxidative hardening at 15 pavements across Texas. Results indicate that typically unmodified binders in pavements oxidize and harden to a degree that exceeds generally accepted pavement aging assumptions. In addition, this hardening may extend much deeper into the pavement than has been previously assumed or documented. Data suggest that pavements can oxidize at surprisingly uniform rates with depth once early oxidation occurs and that these rates continue for an extended time. As a rough measure, 1 month environmental room aging of 1-mm neat binder films at 60°C was equivalent to about 15 months in Texas Highway 21 after the early higher hardening rate period.

Original languageEnglish
Title of host publicationBituminous Materials and Nonbituminous Components of Bituminous Paving Mixtures 2006
PublisherNational Research Council
Number of pages9
ISBN (Print)0309099714, 9780309099714
Publication statusPublished - 2006
Externally publishedYes

Publication series

NameTransportation Research Record
ISSN (Print)0361-1981

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Mechanical Engineering


Dive into the research topics of 'Binder oxidative aging in Texas pavements: Hardening rates, hardening susceptibilities, and impact of pavement depth'. Together they form a unique fingerprint.

Cite this