WEATHERING OF ROAD TAR - PARTS I AND II

CRUDE TARS FROM SIX SOURCES HAVE BEEN USED IN A FULL-SCALE EXPERIMENT TO DETERMINE THE PHYSICAL AND CHEMICAL CHANGES THAT OCCUR IN ROAD TAR USED IN WEARING-COURSE MACADAM. SAMPLES TAKEN FROM THE ROAD AT INTERVALS UP TO TWO YEARS HAVE BEEN STUDIED IN THE LABORATORY. IT HAS BEEN SHOWN THAT WHEN TARS WEATHER, THERE IS AN INCREASE IN VISCOSITY DUE TO TWO MAIN PROCESSES, EVAPORATION AND OXIDATION. IN THE OXIDATION MECHANISM, "C-SUB2 RESIN", SOLUBLE IN PYRIDINE BUT BUT NOT IN BENZENE, IS FORMED FROM MATERIAL OF LOWER MOLECULAR WEIGHT; IT INCREASES BOTH THE VISCOSITY AND THE TEMPERATURE COEFFICIENT OF VISCOSITY, SO THAT IN COLD WEATHER VERY HIGH VISCOSITIES ARE ATTAINED. IN THE CASE OF LOWER-GRAVITY TARS, EVAPORATION AND OXIDATION ACCOUNT FOR SIMILAR AMOUNTS OF HARDENING, BUT WITH COKE-OVEN TARS, EVAPORATION PREDOMINATES. PART II REPORTS ON USE OF THE SAME TECHNIQUES TO DETERMINE IF CHEMICAL CHANGES OCCURRING DURING THE WEATHERING OF ROAD TAR COULD BE DETECTED AND TO OBTAIN INFORMMATION ON THE NATUR OF THESE CHANGES. THE MAIN CHANGES WERE ATTRIBUTABLE TO EVAPORATION AND CONDENSATION, AND CHEMICAL CHANGES DUE TO THE ACTION OF AIR AND LIGHT PLAY A RELATIVELY MINOR PART. /AUTHOR/

  • Supplemental Notes:
    • Vol 19, No 10, PP 273-291
  • Corporate Authors:

    Academic Press Incorporated

    24-28 Oval Road
    London NW1 7DX,   England 
  • Authors:
    • GREEN, E H
    • Bartle, K D
    • Smith, J A
    • Wilman, W G
  • Publication Date: 1969-10

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Filing Info

  • Accession Number: 00207070
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 6 1970 12:00AM