HARDENING OF ASPHALT CEMENTS BY EXPOSURE TO ULTRAVIOLET AND SHORT WAVE LENGTH VISIBLE LIGHT

GRADES AC-10 AND AC-20 OF ASPHALS 6, 3, AND 11 WERE HARDENED TO DIFFERENT DEGREES BY IRRADIATION WITH LIGHT RANGING IN WAVE LENGTH FROM 3200 TO 4200 ANGSTROMS. IT IS CONCLUDED: (1) ASPHALT 6 HARDENS MUCH MORE UNDER THE TEST CONDITIONS THAN DO ASPHALTS 3 AND 11, WHICH ARE AFFECTED TO ABOUT THE SAME DEGREE. (2) THE DEGREE OF HARDENING BY IRRADIATION IS DIFFERENT FROM THE EFFECT OF HEAT, AIR, AND TIME IN THE ABSENCE OF SHORT WAVE LENGTH LIGHT. UNDER THE LATTER CONDITION ASPHALT 6 HARDENS THE LEAST, ASPHALTS 3 AND 11 TO ABOUT THE SAME EXTENT. AND (3) THE AMOUNTS OF NICKEL AND ZINC IN THE ASPHALTS VARIED. ASPHALT 6, WHICH HARDENED THE MOST WHEN EXPOSED TO ULTAVIOLET LIGHT CONTAINED THE LARGEST AMOUNT OF BOTH METALS. ASPHALT 11 HAD THE LEAST AMOUNT OF NICKEL AND SHOWED THE LEAST RELATIVE HARDENING. ASPHALT 3 WAS INTERMEDIATE IN BOTH NICKEL CONTENT AND SUSCEPTIBILITY TO HARDENING.

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Filing Info

  • Accession Number: 00211401
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 23 2000 12:00AM