COOPERATIVE STUDY OF PAVEMENT THICKNESS

THE COMMITTEE ON FLEXIBLE PAVEMENT DESIGN WAS ATTEMPTING TO DEVELOP INFORMATION FROM COOPERATIVE TESTING OF MATERIALS WHICH WOULD SERVE TO COMPARE THE MANY DIFFERENT METHODS CURRENTLY IN USE FOR DETERMINING THE THICKNESS OF FLEXIBLE PAVEMENTS. IN THE EXPECTATION THAT DEFINITE INFORMATION WOULD BE OBTAINED REGARDING THE NECESSARY THICKNESS OF THE PAVEMENT IN THE WASHO ROAD TEST TO CARRY CERTAIN PRESCRIBED LOADS, THE COMMITTEE DECIDED THAT THE MATERIALS COMPOSING THIS PAVEMENT SHOULD BE USED AS A BASIS OF THE STUDY. SAMPLES OF THE SUBGRADE SOIL, BASE AND SUBBASE MATERIALS WERE FURNISHED TO 19 STATE HIGHWAY DEPARTMENT LABORATORIES WITH THE REQUEST THAT AFTER STUDYING THE MATERIALS THEY SUBMIT AN ESTIMATE OF (1) THE THICKNESSES OF PAVEMENT STRUCTURE NECESSARY TO WITHSTAND 200,000 TRIPS OF EACH OF THE FOUR TEST VEHICLES, AND (2) THE NUMBER OF TRIPS FOR EACH OF THE FOUR VEHICLES THAT WOULD PRODUCE FAILURE OF THE VARIOUS SECTIONS OF THE TEST PAVEMENT. FOR THE TEST SECTIONS HAVING 2-IN. BITUMINOUS SURFACES THE AVERAGE ESTIMATED TOTAL THICKNESSES OF PAVEMENT AS REPORTED BY THE PARTICIPANTS AGREED WITH THE THICKNESSES WHICH, BY TRAFFIC TESTING, WERE FOUND TO BE SUFFICIENT FOR THE RESPECTIVE LOADS. HOWEVER, FOR THE SECTIONS HAVING 4-IN. BITUMINOUS SURFACES THE AVERAGE ESTIMATED THICKNESSES (SURFACE, BASE AND SUBBASE) REPORTED WERE CONSIDERABLY GREATER THAN THOSE FOUND FROM THE ROAD TESTS TO BE ACTUALLY NECESSARY. WITH RESPECT TO THE ESTIMATES OF THE NUMBER OF TRIPS NECESSARY TO FAIL THE VARIOUS SECTIONS OF THE TEST ROAD THERE WAS A LARGE DIVERSITY IN THE ANSWERS, CLEARLY INDICATING THAT MUCH MORE ATTENTION AND STUDY SHOULD BE DEVOTED TO THIS PHASE OF PAVEMENT DESIGN. /AUTHOR/

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  • Accession Number: 00205723
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Apr 28 1994 12:00AM