DEVELOPMENT OF A LABORATORY DURABILITY TEST FOR ASPHALTS
A LABORATORY TEST PROCEDURE FOR EVALUATING THE DURABILITY OF PAVING ASPHALTS IS PROPOSED WHICH RECOGNIZES AND IS INTENDED TO SIMULATE THE TWO-STAGE HARDENING OF ASPHALT DURING MIXING PROCESSES AND SUBSEQUENT PAVEMENTS SERVICE LIFE. THE TEST CONSISTS OF FIRST SUBJECTING THE ASPHALT TO THE THIN FILM OVEN TEST (TFOT) AND THEN TREATING THE RESIDUE IN OXYGEN AT HIGH PRESSURES. THE TFOT AT 325 F IS TO SIMULATE THE CHANGES THAT MAY OCCUR IN ASPHALT DURING HOT- MIXING AND THE PRESSURE-OXIDATION PROCESS AT 150 F IS TO SIMULATE THE CHANGES THAT MAY OCCUR IN ASPHALT DURING PAVEMENT SERVICE LIFE. A 1/8-IN. FILM THICKNESS IS USED IN BOTH TREATMENTS. THE EFFECTIVENESS OF THE PROPOSED TEST IN ACCELERATING THE HARDENING AND OTHER CHANGES OF ASPHALT, THE ABILITY OF THE TEST IN DIFFERENTIATING ASPHALTS WITH RESPECT TO CHANGES (BOTH PHYSICAL AND CHEMICAL), AND THE EFFECTS OF TIME AND OXIDATION PRESSURE ARE DEMONSTRATED BY RESULTS OF THE PROPOSED DURABILITY TEST ON FIVE 85-100 PENETRATION GRADE ASPHALT CEMENTS AND ONE OF 120-150 PENETRATION GRADE. THE PROPERTIES MEASURED TO INDICATE CHANGES INCLUDE PENETRATION, SOFTENING POINT, ABSOLUTE VISCOSITY, ASPHALTENE CONTENT, AND PERCENT OXYGEN. THE MAJOR CONCLUSIONS FROM THIS STUDY ARE THAT (1) THE APPROACH OF THE PROPOSED DURABILITY TEST IS SOUND AND THE PROCEDURE REPRODUCIBLE, (2) THE PROCEDURE IS CAPABLE OF ACCELERATING THE HARDENING OF ASPHALT IN A RELATIVELY SHORT PERIOD OF TIME, (3) DIFFERENCES EXIST AMONG ASPHALTS IN HARDENING DURING THE PRESSURE-OXIDATION PROCEDURE, AND THEREFORE THE PROCEDURE CAN DISTINGUISH BETWEEN ASPHALTS THAT ARE SUSCEPTIBLE TO HARDENING AND THOSE THAT ARE NOT, (4) THE HARDENING IN THE PRESSURE-OXIDATION PROCESS IS A HYPERBOLIC FUNCTION OF TIME, WHICH SUGGESTS THAT A DEFINITE CORRELATION CAN BE ESTABLISHED BETWEEN FIELD HARDENING AND THE PROPOSED LABORATORY DURABILITY TEST, AND (5) CONTINUED STUDY INTO THE NEXT PHASE OF THE DURABILITY TEST INVESTIGATION IS NECESSARY AND WARRANTED SO THAT INFORMATION OBTAINED CAN BE PUT INTO USEFUL AND APPLIED FORM IN ASPHALT PAVING DESIGN AND QUALITY CONTROL. /AUTHOR/
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Supplemental Notes:
- Paper sponsored by Committee on Characteristics of Bituminous Materials and presented at the 47th Annual Meeting. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
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Authors:
- Lee, Dah-Yinn
- Publication Date: 1968
Media Info
- Media Type: Print
- Features: Figures; References; Tables;
- Pagination: pp 34-49
- Monograph Title: Physical factors affecting the durability of asphaltic pavements
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Serial:
- Highway Research Record
- Issue Number: 231
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Asphalt; Asphalt cement; Asphalt hardening; Asphalt pavements; Asphaltene; Bituminous mixtures; Bituminous pavements; Durability; Hot mix asphalt; Hyperbolic functions; Laboratory tests; Mixing; Oven tests; Oxidation; Oxygen content; Quality control; Service life; Softening point; Soil penetration test; Thin films; Time; Viscosity
- Uncontrolled Terms: Thin film oven test
- Old TRIS Terms: Softening point test; Viscosity test
- Subject Areas: Design; Highways; Materials;
Filing Info
- Accession Number: 00211348
- Record Type: Publication
- Files: TRIS, TRB
- Created Date: Oct 14 1994 12:00AM