STATEWIDE FOLLOW-UP DEFLECTION STUDY OF OVERLAYS AND ROADWAY RECONSTRUCTION

THE PRIMARY PURPOSE OF THE FIRST PART OF THE STUDY IS TO ESTABLISH, FOR FLEXIBLE PAVEMENTS, A CORRELATION BETWEEN TOLERABLE DEFLECTION, STRUCTURAL DESIGN AND TRAFFIC LOADINGS . THIS COMPRISES ANNUAL DEFLECTION AND RUT DEPTH MEASUREMENTS, AND CRACK SURVEYS ON SELECTED TEST SECTIONS HAVING VARIOUS STRUCTURAL DESIGNS. ASPHALT CONCRETE CORES ARE OBTAINED FROM EACH TEST SECTION AND ARE SUBJECTED TO THE FOLLOWING LABORATORY TESTS: /1/ EXTRACTION AND GRADATION, /2/ PENETRATION, DUCTILITY AND SOFTENING POINT OF THE RECOVERED ASPHALT, /3/ DENSITY AND VOID CONTENT, /4/ STABILITY, /5/ COHESION, /6/ WATER PERMEABILITY AND, /7/ CENTER-POINT LOADING SIMPLE BEAMS, DEFLECTIONS ARE MEASURED IN THE SPRING BY THE CALIFORNIA TRAVELING DEFLECTOMETER. A TRAFFIC INDEX IS DETERMINED FOR EACH SECTION. THE SECOND PART OF THE STUDY RELATES TO THE DETERMINATION OF THE DEFLECTION ATTENUATION RESULTING FROM VARIOUS THICKNESSES OF RESURFACING ON SELECTED FLEXIBLE PAVEMENTS HAVING DIFFERENT DESIGNS. IN THE THIRD PORTION OF THE STUDY, RELATIONS BETWEEN PAVEMENT DEFLECTION, SURFACE CURVATURE AND PAVEMENT PERFORMANCE ARE BEING INVESTIGATED. A MEASURE OF CURVATURE IS OBTAINED BY THE DEHLEN CURVATURE METER. THE FOLLOWING PRINCIPAL FINDINGS ARE REPORTED: /1/ DEFLECTIONS TEND TO DECREASE DURING THE FIRST 3 YEARS OF PAVEMENT LIFE AND INCREASE AFTER ABOUT 4 YEARS, /2/ PENETRATION TEST RESULTS ON RECOVERED ASPHALT IS GENERALLY RELATED TO THE AIR VOID CONTENT AND FILM THICKNESS, /3/ THERE IS AN INCREASE IN THE RATE OF DEFLECTION ATTENUATION AS THE THICKNESS OF RESURFACING IS REDUCED, AND /4/ THE RADIUS OF CURVATURE IS INDIRECTLY RELATED TO THE DEFLECTION. ALTHOUGH THE CURVATURE METER IS THE MORE SENSITIVE, NEITHER TYPE OF MEASUREMENT SHOWS SUPERIORITY AS A PREDICTOR OF PAVEMENT PERFORMANCE. /BPR/

  • Supplemental Notes:
    • Hpr-1/4/, STATE NO D-5-5, BPR 98
  • Corporate Authors:

    California Division of Highways

    Bridge Department
    Sacramento, CA  USA  05914
  • Authors:
    • Forsyth, R
    • Hannon, J
  • Publication Date: 1966-8

Subject/Index Terms

Filing Info

  • Accession Number: 00206290
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Files: TRIS
  • Created Date: Feb 15 1994 12:00AM