RESPONSE OF A FLEXIBLE PAVEMENT TO REPETITIVE AND STATIC LOADS

THE STRAINS AND DEFLECTIONS OBSERVED UPON LOADING A FULL-SCALE, ASPHALTIC CONCRETE PAVEMENT MODEL WITH A WATER-FILLED BAD ARE DESCRIBED. THE SPECIMEN, 10 BY 10 BY 8 FT DEEP, WAS CAREFULLY PREPARED TO ENSURE UNIFORM MATERIALS WHOSE PROPERTIES COULD BE REPRODUCED. TESTS WERE CONDUCTED AT CONSTANT TEMPERATURE WITH THREE MODES OF LOADING: (1) 0.1-SEC LOAD AND 0.9-SEC UNLOAD, (2) 0.5-SEC LOAD AND 0.5-SEC UNLOAD, AND (3) CONSTANT LOAD CREEP. CYCLIC TESTS WERE 1,000 CYCLES LONG CREEP TESTS 900 SEC. LOAD INTENSITIES OF 10, 20, 40, AND 80 PSI WERE APPLIED. THE TOTAL DEFLECTIONS OBSERVED WERE VISCOELASTIC IN NATURE AND INCREASED LINEARLY WITH LOAD. THE DYNAMIC COMPONENT OF STRAIN AND OF DEFLECTION WAS ALSO LINEAR. TOTAL DEFLECTIONS AND STRAINS WERE AFFECTED ONLY SLIGHTLY BY CONDITIONING OF THE PAVEMENT WITH INCREASED CYCLES AND AND INTENSITY OF LOAD. THE ACCUMULATED DEFLECTION INCREASED LINEARLY WITH LOAD, BUT DURING A TEST THE DEFLECTION AT A DISTANCE OF 12 TO 20 IN. FROM THE CENTER OF LOAD WOULD EVENTUALLY DECREASE WITH INCREASE IN REPETIONS. THIS RISE IN THE PAVEMENT IS BELIEVED DUE TO A DIFFERENTIATION OF VISCOELASTIC PROPERTIES WITH DEPTH AT LOCATIONS DETERMINED BY THE GEOMETRY OF THE PAVEMENT AND TO THE LOADED AREA. STRAINS SHOW A SIMILAR PHENOMENON IN SIMILAR LOCATIONS ON THE SURFACE FROM THE BEGINNING OF LOADING, BEING TENSILE UPON LOAD AND ACCUMULATING COMPRESSIVE STRAIN. THE STRAINS WERE SMALL, UNDER 30 MICROIN. PER IN. IN THE AREAS AFFECTED BY DIRECTIONAL REVERSAL. THE LARGEST STRAIN MEASURED WAS 470 MICROIN. PER IN. FURTHER RESEARCH IS NEEDED TO EXPLAIN THE "12-IN. RISE" AND THE OPPOSITE ACCUMULATION OF STRAIN. /AUTHOR/

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 40-54
  • Monograph Title: Theory of pavement design
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00205865
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jun 11 1971 12:00AM