A PRACTICAL METHOD FOR DETERMINING THE GLASS TRANSITION TEMPERATURE OF ASPHALTS AND CALCULATION OF THEIR LOW TEMPERATURE VISCOSITIES

THE PROPERTIES OF ASPHALT CONCRETE (AC) MIXES CHANGE IN ACCORDANCE WITH CHANGES IN THE PROPERTIES OF THE ASPHALT BINDER. BECAUSE VISCOSITIES ARE USUALLY CONSIDERED TO BE A FUNDAMENTAL MEASURE OF ASPHALT PROPERTIES, THEY ARE THE PRIMARY PROPERTY INCLUDED IN ASPHALT SPECIFICATIONS. UNFORTUNATELY, DETERMINATION OF VISCOSITY AT LOW AMBIENT TEMPERATURES IS DIFFICULT AND POORLY REPRODUCIBLE, ESPECIALLY WHEN DIFFERENT APPARATUS AND PROCEDURES ARE USED. A VISCOSITY AT LOW TEMPERATURES CAN BE CALCULATED FROM THE GLASS TRANSITION TEMPERATURE AND A VISCOSITY DETERMINED AT A CONVENIENT HIGHER TEMPERATURE. THE GLASS TRANSITION TEMPERATURE IS THE TEMPERATURE AT WHICH AMORPHOUS POLYMERS CHANGE FROM A GLASSY TO FLUID CONDITION. THIS PAPER DESCRIBES A CONVENIENT METHOD FOR DETERMINING THE GLASS TRANSITION TEMPERATURE OF ASPHALTS AND PRESENTS GLASS TRANSITION TEMPERATURE VALUES OBTAINED BY THIS PROCEDURE FOR 52 PAVING ASPHALTS SUPPLIED BY THE BUREAU OF PUBLIC ROADS (BPR) THAT ARE REPRESENTATIVE OF COMMERCIAL PRODUCTION IN THE UNITED STATES. BASED ON THESE MEASUREMENTS, AS WELL AS VISCOSITY MEASUREMENTS, NEW CONSTANTS ARE SUGGESTED FOR USE IN THE WILLIAMS-LANDEL-FERRY (WLF) EQUATION FOR CALCULATING ASPHALT VISCOSITIES AT LOW TEMPERATURES. TO SIMPLIFY THESE CALCULATIONS A NOMOGRAPH IS ALSO PRESENTED. A COMPARISON IS MADE OF 728 EXPERIMENTALLY AND CALCULATED VISCOSITIES. THIS COMPARISON, TOGETHER WITH CONSIDERATION OF THE PRINCIPLES ON WHICH THE WLF EQUATION AND THE TIME-TEMPERATURE SUPERPOSITION SHIFT ARE BASED, RAISES A QUESTION AS TO THE VALUE OF VISCOSITIES MEASURED AT LOW TEMPERATURES BY CURRENT PROCEDURES FOR QUANTITATIVELY RELATING THE BEHAVIOR OF ASPHALTS. THE GLASS TRANSITION TEMPERATURE METHOD IS PROPOSED AS A PHYSICAL PARAMETER OF SPECIAL UTILITY IN ADDITION TO THE VISCOSITY IN INTERPRETING LOW TEMPERATURE SERVICE BEHAVIOR OF ASPHALTS. /AUTHOR/

• Supplemental Notes:
  • Vol 35, pp 61-90, 9 FIG, 2 TAB, 31 REF, 1 APP
• Authors:
  • Schmidt, R J
  • Santucci, L E
• Conference:
  • Assoc Asphalt Paving Technol Proc
• Publication Date: 1966-2

Subject/Index Terms

• TRT Terms: Asphalt concrete; Binders; Calculation; Glass; Low temperature tests; Nomographs; Test procedures; Viscosity
• Uncontrolled Terms: Computation; Glass transition temperature
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 00210792
• Record Type: Publication
• Files: TRIS
• Created Date: May 6 1994 12:00AM