EFFECT OF MIXING TEMPERATURE ON HARDENING OF ASPHALTIC BINDER IN HOT BITUMINOUS CONCRETE

PLANT MIXES OF HOT BITUMINOUS CONCRETE WERE MADE IN THE MIXING TEMPERATURE RANGE OF 250 TO 400F, CORRESPONDING TO VISCOSITY LIMITS OF APPROXIMATELY 400 TO 15 SAYBOLT FUROL SECONDS. THE ASPHALT FROM SAMPLES OF THESE MIXES WAS RECOVERED BY THE MODIFIED ABSON METHOD, AND CHANGES IN THE PENETRATION, DUCTILITY, SOFTENING POINT, AND ABSOLUTE VISCOSITY WERE MEASURED. ASPHALTS FROM VENEZUELAN AND EAST TEXAS CRUDES WERE USED. THE MIXES USED WERE BASE COURSES, BINDER COURSES, WEARING SURFACES, AND CERTAIN CITY STREET MIXES. THE AGGREGATES WERE VARIED AND WERE EITHER ALL GRANITE OR MIXTURES OF GRANITE, SAND, AND MINERAL FILLER, MIXTURES OF SANDY LIMESTONE, SAND AND MINERAL FILLER, OR MIXTURES OF SILICEOUS GRAVELS, SAND, AND MINERAL FILLER. SOME OF THE SAMPLES WERE COOLED SLOWLY, WHEREAS OTHERS WERE COOLED RAPIDLY BY QUENCHING IN WATER. THE SAMPLES COOLED SLOWLY SHOWED 65 TO 75 PERCENT PENETRATION RETAINED AT 250F WITH AN ADDITIONAL 10 PERCENT DROP IN PERCENT PENETRATION RETAINED FOR EACH 50F INCREASE IN MIXING TEMPERATURE. THE SAMPLES QUENCHED IN WATER SHOWED ESSENTIALLY NO DIFFERENCE IN HARDENING AT 250 F FROM SLOWLY COOLED. NO DEFINITE DIFFERENCE IN HARDENING WAS FOUND FOR DIFFERENT ASPHALTS, DIFFERENT MIXES, DIFFERENT AGGREGATES, OR DIFFERENT TYPE PUGMILLS. SAMPLES OF PAVING MIXTURE WERE FOUND TO HARDEN APPRECIABLY ON STORAGE DURING THE FIRST 15 DAYS, BUT THEREAFTER THE RATE OF HARDENING WAS VERY SLOW. /AUTHOR/

Media Info

  • Media Type: Print
  • Features: Appendices; Figures; References; Tables;
  • Pagination: pp 20-38
  • Monograph Title: Factors influencing setting and hardening of asphalt in bituminous pavements
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00210835
  • Record Type: Publication
  • Files: TRIS, TRB, ATRI
  • Created Date: Jul 6 1970 12:00AM