PART I HARDENING OF ASPHALT IN HOT BITUMINOUS BASE, BINDER, AND SAND MIXTURES

THE EFFECT OF THE VISCOSITY OF THE ASPHALTIC BINDER ON THE MIXING, LAYING, AND COMPACTION OF HOT BITUMINOUS BASE, BINDER, AND SAND ASPHALT MIXES WAS INVESTIGATED AND THEIR PERFORMANCE IN TEST STRIPS UNDER TRAFFIC OBSERVED. FOUR TEST STRIPS WERE LAID FOR EACH OF THE MIXES IN WHICH THE MIX VISCOSITY OF THE ASPHALTIC BINDER WAS VARIED APPROXIMATELY FROM 20 TO 3.75 POISES. TEMPERATURES WERE MEASURED IN THE PAVEMENT AT FOUR DIFFERENT ELEVATIONS DURING ROLLING OPERATIONS. ROSS COUNTS WERE MADE ON THE BASE AND BINDER MIXES AS THEY LEFT THE MIX BOX, LAYING CHARACTERISTICS OF THE MIXES WERE OBSERVED, AND DENSITIES MEASURED ON THE FINISHED PAVEMENTS. SAMPLES OF PAVEMENT WERE TAKEN IMMEDIATELY AFTER LAYING, AFTER 10 MONTHS AND AFTER 21 OR 22 MONTHS, AND THE ASPHALT EXTRACTED AND RECOVERED. PENETRATIONS AND VISCOSITIES WERE DETERMINED ON THE RECOVERED ASPHALTS. ROSS COUNTS AND VISUAL INSPECTION SHOWED INCOMPLETE COATING OF THE AGGREGATE FOR ALL MIXES AT THE HIGH MIX VISCOSITIES. BASE AND BINDER MIXES LAID SATISFACTORY AT ALL MIX TEMPERATURES BUT THE SAND ASPHALT SHOWED SOME TEARING AT THE HIGHER MIX VISCOSITIES. THERE WAS DEFINITELY GREATER HARDENING IN THE MIX BOX WITH INCREASED MIX TEMPERATURE. HOWEVER, AS THE STRIPS AGED THIS RELATIONSHIP SHOWED SOME CHANGE. THE BASE AND BINDER MIXES MADE AT 250 F SHOWED THE LEAST HARDENING AFTER 10 MONTHS AND 22 MONTHS SERVICE. SAND ASPHALT STRIPS SHOWED SIMILAR HARDNESS AFTER 21 MONTHS. THE THICKER PAVEMENT LAYERS HARDENED MORE SLOWLY THAN THIN LAYERS.

  • Supplemental Notes:
    • Final ReporT, 83 PP, 14 FIG, 35 TAB, 2 REF, 1 APP
  • Corporate Authors:

    North Carolina State University, Raleigh

    School of Engineering
    Raleigh, NC  United States  27695
  • Authors:
    • BRIGHT, R
    • Justice, A
    • Steele, J
  • Publication Date: 1966-7

Subject/Index Terms

Filing Info

  • Accession Number: 00210698
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 16 1994 12:00AM