SUMMARY ROADWAY FAILURE STUDY NO. II-FINAL REPORT

SUMMARY IS PRESENTED OF MAJOR ACCOMPLISHMENTS ON THE LATERAL CRACKING OF ASPHALTIC CONCRETE AND THE BEHAVIOR AND STABILIZATION OF EXPANSIVE CLAY SOILS. THE RELATIONSHIP WAS EXAMINED OF ASPHALT AGING TO THE ALTERATION OF MIX PROPERTIES AND TO THE VARIATION IN FREQUENCY OF LATERAL CRACKING OF ASPHALTIC CONCRETE PAVEMENTS. TEMPERATURE DIFFERENTIALS WERE OBSERVED AT THREE TEST SITES DURING THE WINTER PERIOD. THE WIDTH OF ARTIFICIAL JOINTS INCREASED WITH DECREASE OF PAVEMENT TEMPERATURE. ARTIFICIAL JOINTS OR WEAKNESS PLANES, AT 5-FT. SPACING, WERE EFFECTIVE IN CONTROLLING LATERAL CRACKING. SUBGRADE FRICTION TESTS WERE CONDUCTED BY MEASURING THE HORIZONTAL FORCE NECESSARY TO CAUSE MOVEMENT OF THE PAVEMENT ON THE SUBGRADE. IN LABORATORY TESTS, ELASTIC MODULUS, ULTIMATE STRENGTH IN TENSION AND LINEAR THERMAL EXPANSION COEFFICIENT WERE DETERMINED ON INITIAL AND AGED PAVEMENT SPECIMENS. ASPHALT COMPOSITION CHANGED WITH INCREASING AGE IN PAVEMENT AREAS HAVING LATERAL CRACKING. HIGHER DEGREES OF HARDENING OF ASPHALTS OCCURRED IN PAVEMENTS WITH HIGH AIR VOID CONTENTS. DIFFERENCES IN PAVEMENT PERFORMANCE WERE RELATED TO ASPHALT STIFFNESS AND FILLER CONCENTRATION. INCREASED FILLER CONTENT PRODUCED INCREASED STIFFNESS OF THE RESULTING MIXTURES IN STUDY OF THE TEMPERATURE-DEPENDENT CONSISTENCY OF ASPHALTS IN COMBINATION WITH VARIOUS CONCENTRATIONS OF MINERAL FILLERS. PREMIXING OF ASPHALT WITH FILLER, FOLLOWED BY ADDITION OF THE REMAINING AGGREGATE, PRODUCED MIXTURES WITH HIGHER MARSHALL STABILITIES. PLANE THERMAL STRESSES AND THERMAL WARPING STRESSES ANALYZED USING WESTERGAARD EXPRESSIONS AND A COMPUTER SOLUTION SHOWED THAT THE COMPUTED LONGITUDINAL WARPING STRESSES COULD EXCEED THE OBSERVED ULTIMATE TENSILE STRENGTHS ALTHOUGH THE OBSERVED PAVEMENTS DID NOT EXPERIENCE LATERAL CRACKING DURING THEIR EARLY LIFE. SUBSTUDIES WERE CONDUCTED TO: DETERMINE THE SOURCE OF WATER INFILTRATING AND EXPANSIVE CLAY SUBGRADE BENEATH A FLEXIBLE PAVEMENT, DETERMINE THE SWELL POTENTIAL OF INSITU EXPANSIVE CLAY, EVALUATE SOIL STABILIZERS AND SEALANTS IN THE LABORATORY. IT WAS DETERMINED THAT THE PRIMARY SOURCE OF THE WATER ENTERING THE SANDSTONE SUBBASE WAS THROUGH THE SHOULDER AREAS AND SIDE SLOPES. THIS WAS EFFECTIVELY REDUCED BY PLACING A PLASTIC MEMBRANE WITHIN THE SUBBASE AND EXTENDING THROUGH THE SHOULDER TO THE DITCH LINE. ABSORPTION OF WATER AND CONSEQUENT ELEVATION CHANGE WERE RELATIVELY SLOW DURING THE TEST PERIOD. LABORATORY TESTS SHOWED THAT NO STABILIZERS MIGRATED APPRECIABLY FROM THE POINT OF APPLICATION AND PENEPRIME AND CATALYTICALLY BLOWN ASPHALT WERE EFFECTIVE SEALANTS.

  • Corporate Authors:

    University of Wyoming, Laramie

    Wyoming Survey and Analysis Center, 710 Garfield
    Laramie, WY  United States  82070

    Bureau of Public Roads /US

    400 7th Street, SW
    Washington, DC  United States  20590
  • Authors:
    • Lamb, D R
    • SCOTT, W G
    • Gietz, R H
    • Armijo, J D
  • Publication Date: 1967-8

Subject/Index Terms

Filing Info

  • Accession Number: 00206320
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Report/Paper Numbers: Hpr-1(4)
  • Files: TRIS
  • Created Date: Jan 16 1994 12:00AM