FLEXIBLE PAVEMENT EVALUATION STUDY

THE PRESENT METHOD OF DESIGNING HIGH-TYPE FLEXIBLE PAVEMENTS ON WASHINGTON STATE HIGHWAYS HAS BEEN IN USE SINCE 1950. IN 1962, A RESEARCH PROGRAM WAS INSTITUTED TO EVALUATE ROADWAYS CONSTRUCTED WITH CEMENT TREATED BASE (CTB) BY THIS DESIGN METHOD. ABOUT 120 PROJECTS WERE STUDIED. THE PROGRAM INCLUDES THE FOLLOWING ITEMS: (1) REVIEW OF PLANS, SPECIFICATIONS, AND CONSTRUCTION RECORDS OF ALL HIGH-TYPE FLEXIBLE PAVEMENTS BUILT SINCE 1950, (2) VISUAL INSPECTION AND RATING OF EACH SECTION OF ROADWAY, (3) CORRELATION BETWEEN PAVEMENT DISTRESS AND DEFLECTION MEASURED BY THE BENKELMAN BEAM AND THE CALIFORNIA TRAVELING DEFLECTOMETER, (4) SAMPLING AND TESTING OF THE PAVEMENT SYSTEM MATERIALS INCLUDING DETERMINATIONS OF ASPHALT OR CEMENT CONTENT, DENSITY, GRADATION, ETC. AND THE RESILIENCE OF SUBGRADE MATERIALS USING THE CALIFORNIA RESILIOMETER. THE FOLLOWING FINDINGS ARE REPORTED: (1) DESIGN METHODS USED ARE PRODUCING PAVEMENTS CAPABLE OF PROVIDING GOOD SERVICE FOR THE DESIGN LIFE, (2) LACK OF UNIFORM CEMENT DISPERSION HAS BEEN A PRIMARY SOURCE OF EARLY DISTRESS IN CTB PAVEMENTS, PARTICULARLY IN ROADMIX TYPE OF CONSTRUCTION, (3) CEMENT CONTENT IS CRITICAL AND MUST BE SUFFICIENT TO INSURE ADEQUATE COMPRESSIVE STRENGTH, BUT NOT EXCESSIVE TO THE POINT WHERE EXCESSIVE SHRINKAGE OCCURS, (4) EVEN WITH PROPER DESIGN AND CONTROL OF CONSTRUCTION, SOME CRACKING APPEARS TO BE INESCAPABLE, (5) DEFLECTION TESTING IS A VALUABLE TOOL IN DIAGNOSING PREMATURE PAVEMENT FAILURE AND IN DETERMINING THE MOST SUITABLE CORRECTIVE ACTION, AND (6) THE CHLOE PROFILOMETER DOES NOT APPEAR TO BE SUITABLE FOR EVALUATING LENGTHY SECTIONS OF ROADWAY BECAUSE OF THE SLOW OPERATING SPEED AND QUESTIONABLE REPEATABILITY OF READINGS. A SYSTEM FOR EVALUATING THE PRESENT CONDITION OF ROADWAY SURFACES, WHICH CAN ALSO BE USED IN SCHEDULING TIMELY REHABILITATION OF ALL PAVEMENT TYPES, HAS BEEN DEVELOPED. /BPR/

  • Supplemental Notes:
    • Hpr-1(4), STATE: HR-179, BPR:4
  • Corporate Authors:

    Washington State Department of Highways

    Olympia, WA  USA 

    Bureau of Public Roads /US

    400 7th Street, SW
    Washington, DC  USA  20590
  • Authors:
    • Marshall, T R
  • Publication Date: 1969-6-13

Subject/Index Terms

Filing Info

  • Accession Number: 00206378
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Files: TRIS, STATEDOT
  • Created Date: Oct 7 1994 12:00AM