LABORATORY AGING AND ANNEALING OF ASPHALT BINDERS BY MICROWAVE RADIATION

A household microwave oven with a frequency of 2,450+/-13 MHz and an output power of 1000 W is used to simulate short- and long-term aging of asphalt, and for annealing, prior to sampling, to remove steric (isothermal) hardening. A quartz petri dish holds the asphalt during microwave treatment, at atmospheric pressure. To simulate thin film oven (TFO) aging, a 10-g sample is microwaved for a total of 33 min. For 11 asphalts, the average difference in G*/sin delta, at limiting high temperature, between TFO and microwave aging is +/-0.68 kPa. Simulating rolling thin-film oven (RTFO) aging is possible by microwaving for a total of 63 min. For 18 asphalts, the average difference in G*/sin delta, at limiting high temperature, between RTFO and microwave aging is +/-1.19 kPa. Aging by RTFO + pressure aging vessel (PAV) and TFO + PAV is simulated by microwaving for a total of 158 min. Microwave aging marginally underestimates long-term aging. For 18 asphalts, the average difference in intermediate temperature obtained after RTFO + PAV versus microwave aging is -2.8 deg C; for TFO + PAV versus microwave aging, the average difference is -2.7 deg C. Annealing for 2 hr at 150 deg C in a convection oven (conductive heating) is simulated by microwaving for a total of 27 min. The average difference in G*/sin delta between the two methods is +/-0.24 kPa. Molecular size index (MSI, the ratio of first to second fraction from size exclusion chromatography) correlates with stiffness at low temperature. At intermediate temperature, tan delta remains practically unchanged until MSI reaches a minimum, then increases sharply. At limiting high temperature, G* does not correlate with MSI.

• Record URL:
  https://doi.org/10.3141/1535-13
• Summary URL:
  http://scholar.google.com/scholar_lookup?title=LABORATORY+AGING+AND+ANNEALING+OF+ASPHALT+BINDERS+BY+MICROWAVE+RADIATION&author=S.+Bishara&author=R.+McReynolds&publication_year=1996
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309059100
• Supplemental Notes:
  • This paper appears in Transportation Research Record No. 1535, Characteristics of Asphalt Binders.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Bishara, Safwat W
  • McReynolds, R L
• Publication Date: 1996

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 98-107
• Serial:
  • Transportation Research Record
  • Issue Number: 1535
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Aging (Materials); Annealing; Bituminous binders; Laboratory studies; Microwave devices; Microwaves; Ovens
• Uncontrolled Terms: Microwave ovens
• Old TRIS Terms: Microwave radiation
• Subject Areas: Highways; Materials; I31: Bituminous Binders and Materials;

Filing Info

• Accession Number: 00730238
• Record Type: Publication
• ISBN: 0309059100
• Files: TRIS, TRB
• Created Date: Dec 13 1997 12:00AM