TEST METHODS FOR PERFORMING ACCELERATED DURABILITY TESTS ON ASPHALTS

ACCELERATED WEATHERING MUST BE CARRIED OUT UNDER CONDITIONS CLOSELY RESEMBLING THOSE ENCOUNTERED IN THE FIELD IN ORDER THAT THE METHOD OF MEASUREMENT OF CHANGES IN ASPHALT MAY BE QUANTITATIVE, ACCURATE, AND RAPID, AND THAT THE RESULTS CAN BE CORRELATED WITH FIELD PERFORMANCE. THE DEVELOPMENT IS DISCUSSED OF AN ACCELERATED DURABILITY TEST METHOD. ACCELERATED WEATHERING WAS CONDUCTED IN A UNIT CONTAINING INFRA-RED LAMPS, AND A ROTATING TABLE. TEST MIXTURES WERE MADE WITH A STANDARD OTTAWA SAND AND TWO PERCENT OF ASPHALT. ASPHALTS WERE MIXED AT TEMPERATURES AT WHICH THE VISCOSITY WAS BETWEEN 75 AND 150 SEC. SAYBOLT FUROL. SPECIMENS WERE PREPARED BY COMPRESSING THE MATERIAL INTO SHALLOW MOLDS UNDER A LOAD OF 1000 PSI. ABRASION TESTS WERE CONDUCTED WITH STEEL SHOT. IT WAS NOTED THAT MANY TEST SPECIMENS SHOWED LESS ABRASION LOSS AFTER THE INITIAL PERIOD OF WEATHERING THAN WHEN FRESHLY MOLDED. AFTER FURTHER WEATHERING, HOWEVER, ABRASION LOSS INCREASED. THIS PHENOMENEN WAS ATTRIBUTED TO THE FLOWING TOGETHER OR COALESCING OF THE ASPHALT FILMS UNDER THE COMBINED INFLUENCE OF TIME AND TEMPERATURE. SAMPLES MADE WITH 85-100 PENETRATION ASPHALT AND CURED AT 140 F WITHOUT LIGHT SHOWED A SHARP INCREASE IN ABRASION RESISTANCE AFTER FIVE HOURS, BUT PRACTICALLY NO CHANGE THEREAFTER. IT IS SUGGESTED THAT EACH ASPHALT SHOULD BE SUBJECT TO AN APPROPRIATE PERIOD OF CURING WITH HEAT ALONE TO DEVELOP THE MAXIMUM ABRASION RESISTANCE BEFORE BEING PLACED IN THE WEATHERING MACHINE. IT IS ALSO SUGGESTED THAT THE TEMPERATURE VISCOSITY RELATIONSHIP OF AN ASPHALT SHOULD BE GIVEN AT LEAST AS MUCH CONSIDERATION WHEN FIXING THE MIXING TEMPERATURE AS THE GRADE OF THE ASPHALT OR THE CLIMATIC CONDITIONS AT THE TIME OF CONSTRUCTION.

  • Supplemental Notes:
    • No 94, pp 84-99
  • Authors:
    • STANTON, T E
    • Hveem, F N
  • Publication Date: 1949

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  • Accession Number: 00210866
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 6 1994 12:00AM