DEVELOPMENT OF SPECIFICATIONS FOR VISCOSITY-GRADED ASPHALTS

A COMPREHENSIVE RESEARCH PROGRAMS HAS BEEN CONDUCTED TO DEVELOP FUNDAMENTAL METHODS FOR MEASURING THE CONSISTENCY OF ASPHALTIC MATERIALS AND TO STUDY THE FLOW PROPERTIES OF ASPHALT CEMENTS OVER THE RANGE IN TEMPERATURES ENCOUNTERED IN CONSTRUCTION AND SERVICE IN PAVEMENTS. CONCURRENTLY, A NUMBER OF SPECIFICATIONS USING REQUIREMENTS BASED ON THE NEW FUNDAMENTAL METHODS HAVE BEEN PROPOSED OR USED AS THE BASIS FOR PURCHASING ASPHALT. IN AN ATTEMPT TO GIVE SOME GUIDANCE AND STANDARDIZATION TO THESE SPECIFICATIONS, THE COMMITTEE ON MATERIALS OF THE AMERICAN ASSOCIATION OF STATE HIGHWAY OFFICIALS (AASHO) UNDERTOOK THE DEVELOPMENT OF SPECIFICATIONS BASED ON VISCOSITY GRADING AT 140 F. FOUR GRADES WERE SELECTED, AND LIMITING REQUIREMENTS WERE ADDED FOR VISCOSITY AT 275 F. BECAUSE LOW- TEMPERATURE VISCOSITY TESTS WERE NOT PERFECTED FOR NATIONAL USE, LIMITING REQUIREMENTS USING THE PENETRATION TEST AT 77 F WERE SELECTED. OTHER REQUIREMENTS INCLUDED MAXIMUM VISCOSITY AND MINIMUM DUCTILITY LIMITS ON THE RESIDUE FROM THE THIN-FILM OVEN TEST. CONVENTIONAL SOLUBILITY, FLASH POINT, AND OLIENSIS SPOT TEST REQUIREMENTS ALSO WERE INCLUDED IN THE SPECIFICATION. THE LIMITS FOR THE REQUIREMENTS OF THE 4 GRADES WERE SET BY A SYSTEMATIC STUDY OF TEST CHARACTERISTICS OF ASPHALT CEMENTS PRODUCED IN THE UNITED STATES. THE SPECIFICATION HAS BEEN ADOPTED BY AASHO, DESIGNATED AS SPECIFICATION M 226, AND PUBLISHED AS AN ALTERNATE TO SPECIFICATION M 20, WHICH IS BASED ON PENETRATION GRADING AND REMAINS IN EFFECT. THE ADVANTAGES OF SPECIFICATION M 226 ARE THAT IT PROVIDES INFORMATION ON THE KIND OF ASPHALT BEING USED AND A MEANS FOR SELECTING THE ASPHALT THAT SHOULD RESULT IN IMPROVED MIXTURE DESIGN AND MORE UNIFORM CONSTRUCTION PRACTICES. THIS SHOULD, IN TIME, LEAD TO IMPROVED PAVEMENT PERFORMANCE. /AUTHOR/

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 1-14
  • Monograph Title: Symposium on viscosity grading of asphalts
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00211681
  • Record Type: Publication
  • ISBN: 0309019621
  • Files: TRIS, TRB
  • Created Date: Oct 3 1971 12:00AM