MECHANISM OF TENSILE BEHAVIOR AND FAILURE OF ASPHALT CEMENTS IN THIN FILMS

THE TENSILE BEHAVIOR AND FAILURE CHARACTERISTICS OF ELEVEN ASPHALT CEMENTS IN THIN FILMS WERE STUDIED. VARIABLES IN THE STUDY INCLUDED (1) RATE OF DEFORMATION, (2) TEMPERATURE, (3) ASPHALT CONSISTENCY AND (4) ASPHALT SOURCE AND METHOD OF MANUFACTURE. LITERATURE PERTAINING TO PREVIOUS BEHAVIOR INVESTIGATIONS OF ASPHALT CEMENTS AND SIMILAR MATERIALS WAS REVIEWED AND SUMMARIZED. PARTICULAR EMPHASIS WAS PLACED ON THE BEHAVIOR OF POLYMERIC MATERIALS AND THEORIES USED TO INTERPRET THEIR OBSERVED BEHAVIOR. PHOTOGRAPHIC TECHNIQUES WERE USED DURING A LABORATORY TESTING PROGRAM TO OBTAIN PHOTOGRAPHIC RECORDS OF OBSERVATIONS MADE OF THIN FILM SPECIMENS OF ASPHALT CEMENT THROUGH THEIR THINNEST DIMENSION AS THEY WERE SUBJECTED TO TENSILE STRESSES. MEASUREMENTS, THAT WERE TAKEN FROM THE PHOTOGRAPHIC RECORDS, SIGNIFICANTLY EXTENDED THE KNOWLEDGE OF THE TENSILE BEHAVIOR AND FAILURE CHARACTERISTICS OF ASPHALT FILMS SUBJECTED TO CONTROLLED TEST CONDITIONS. THE INFORMATION OBTAINED WAS RELATED TO THE (1) EXTENT OF CAVITY FORMATION PRIOR TO SPECIMEN FAILURE, (2) AMOUNT OF VOLUME CHANGE TO FAILURE CAUSED BY TENSILE STRESSING, (3) MAGNITUDE OF SPECIMEN DRAW-IN, AND (4) RELATIONSHIP OF EACH OF THE FOREGOING TO THE MAGNITUDE OF TENSILE STRESS AND SPECIMEN FILM THICKNESS. THE TENSILE BEHAVIOR DATA COLLECTED FOR ALL OF THE ASPHALT CEMENTS INVESTIGATED WERE ANALYZED IN DETAIL. A TECHNIQUE WAS THEN DEVELOPED WHICH WOULD ENABLE THE ACCURATE PREDICTION OF THE TENSILE STRENGTH FILM THICKNESS CURVE FOR ANY TYPE OF ASPHALT CEMENT OF NORMALLY USED CONSISTENCY, FOR NORMAL EXPOSURE TEMPERATURES ABOVE THE GLASS TRANSITION TEMPERATURE OF THE MATERIAL, AND FOR RATES OF DEFORMATION RANGING FROM 0.005 TO 1.0 IN./MIN. THE TECHNIQUE REQUIRED KNOWLEDGE ONLY OF A BASE CURVE ESTABLISHED FOR A GIVEN ASPHALT CEMENT AND THE MAGNITUDE OF APPROPRIATE SHIFT FACTORS FOR (1) TEMPERATURE, (2) RATE OF DEFORMATION, AND (3) ASPHALT CEMENT PENETRATION. BASED ON INFORMATION AND CONCEPTS FROM VARIOUS SCIENTIFIC AND ENGINEERING DISCIPLINES, A MECHANISM WAS PROPOSED TO EXPLAIN THE TENSILE BEHAVIOR AND FAILURE CHARACTERISTICS OF ASPHALT CEMENTS IN THIN FILMS. THE MECHANISM RELATES TO MOLECULAR 'CHAIN' RESPONSE WHEN SUBJECTED TO STRESS UNDER VARIOUS COMBINATIONS OF EXTERNAL CONDITIONS. LABORATORY TEST RESULTS WERE CITED TO SUBSTANTIATE THE APPLICABILITY OF THE HYPOTHESIZED MECHANISM TO ASPHALT CEMENTS. /AUTHOR/

  • Supplemental Notes:
    • Hpr-pr-1/3/, BPR-7, IHR-75
  • Corporate Authors:

    University of Illinois, Urbana-Champaign

    Urbana, IL  United States  61801

    Bureau of Public Roads /US

    400 7th Street, SW
    Washington, DC  United States  20590
  • Authors:
    • Marek, C R
  • Publication Date: 1967-6

Subject/Index Terms

Filing Info

  • Accession Number: 00210389
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Files: TRIS
  • Created Date: Apr 12 1994 12:00AM