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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

A MODIFIED PENETRATION INDEX FOR CANADIAN ASPHALTS AND DISCUSSION

THE PURPOSE WAS TO DETERMINE WHETHER OR NOT THE PENETRATION INDEX COULD BE APPLIED TO CANADIAN ASPHALTS AS A REASONABLE TRUE INDICATION OF THEIR RHEOLOGICAL PROPERTIES, AND IF NOT, TO MODIFY IT TO PERMIT ITS USE FOR THE CALCULATION OF THEIR STIFFNESS MODULI. IN THE INITIAL PHASE, THE PENETRATION-TEMPERATURE AND VISCOSITY TEMPERATURE RELATIONSHIPS OF SEVERAL CANADIAN, MEXICAN, VENEZUELAN, AND AMERICAN ASPHALTS WERE DETERMINED. IT WAS FOUND THAT THE ASSUMPTIONS MADE TO DERIVE THE EQUATIONS FOR CALCULATING THE PENETRATION INDEX ARE VALID FOR SOME TYPES OF ASPHALTS BUT NOT FOR MOST CANADIAN ASPHALTS. IN THE SECOND PHASE, A MODIFIED PENETRATION INDEX SUGGESTED BY MCLEOD AND BASED ON THE VISCOSITY-PENETRATION RELATIONSHIP WAS INVESTIGATED. THE RELATIONSHIP BETWEEN VISCOSITY, PENETRATION AND PENETRATION INDEX WAS DETERMINED FOR ASPHALTS FROM UNITED STATES, VENEZUELA AND MIDDLE EAST SOURCES WHOSE PENETRATION INDICES AS CALCULATED BY THE ORIGINAL EQUATIONS ARE IN GOOD AGREEMENT WITH THEIR TEMPERATURE SUSCEPTIBILITIES. FROM THESE DATA THE VISCOSITY-PENETRATION RELATIONSHIPS CORRESPONDING TO PENETRATION INDICES OF 0 AND -1.5 WERE ESTABLISHED AND A CHART WHICH ENABLES THE PENETRATION INDEX TO BE CALCULATED FROM THE PENETRATION AT 77 F AND THE VISCOSITY AT 140 F WAS CONSTRUCTED. UPON APPLICATION OF THIS CHART TO THE ASPHALTS USED IN THE FIRST PHASE OF THIS STUDY IT WAS FOUND THAT THE MODIFIED PENETRATION INDEX OF NON-CANADIAN ASPHALTS CALCULATED FROM THE PENETRATION AT 77 F AND THE VISCOSITY AT 140 F WAS NOT DIFFERENT FROM THAT CALCULATED BY THE ORIGINAL RELATIONSHIPS. /AUTHOR/

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Filing Info

  • Accession Number: 00211663
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 25 1971 12:00AM