APPLICATION OF SONIC AND ULTRASONIC TEST METHODS TO THE MEASUREMENT OF ELASTIC MODULI OF PAVEMENT MATERIALS

THE TECHNIQUES, CONCEPTS AND LIMITATIONS OF ULTRASONIC TESTING AS APPLIED TO BOTH IN-SITU PAVEMENTS AND LABORATORY SPECIMENS OR CORES ARE DISCUSSED TOGETHER WITH THE SELECTION OF TWO TECHNIQUES FOR THE DETERMINATION OF COMPRESSIONAL AND SHEAR WAVE VELOCITIES AND THEIR ASSOCIATED MODULI. THE FIRST USES AN INSTRUMENT PRIMARILY INTENDED FOR THE ULTRASONIC TESTING OF CONCRETE. THIS APPARATUS WAS USED TO ESTABLISH THE CHARACTERISTICS OF LABORATORY PREPARED SPECIMENS OF BITUMINOUS MIXTURES. THE RESULTS WERE COMPARED WITH THOSE OBTAINED FROM THE SECOND METHOD DEVELOPED, USING AN ULTRA SHORT RANGE SEISMIC INSTRUMENT. THE RESULTS FROM THE LATTER INSTRUMENT WERE ALSO ASSESSED AGAINST THOSE OBTAINED WITH LABORATORY RESONANCE AND IN-SITU CONTINUOUS WAVE PROPAGATION TECHNIQUES. NON-DESTRUCTIVE TESTS WERE CARRIED OUT ON TWO MAJOR BASE EXPERIMENTAL SITES BY MEANS OF THE ULTRA SHORT RANGE SEISMIC INSTRUMENT. SHEAR AND BULK ELASTIC MODULI WERE ESTABLISHED FOR FOUR DIFFERENT ROAD BASE MATERIAL TYPES, VIZ. TAR, BITUMEN AND CEMENT BOUND LAYERS AND SOME CRUSHED ROCK BASES. RESULTS SHOW THE TEMPERATURE DEPENDENCE OF THE TAR BOUND MIXTURES WITH RESPECT TO ELASTIC MODULI. LABORATORY TESTS ON A CONTINUOUSLY-GRADED ASPHALTIC CONCRETE AND A GAP-GRADED MIXTURE, COVERING A RANGE OF BINDER CONTENTS AND DEGREES OF COMPACTION, DEMONSTRATED THE MARKED DEPENDENCE OF THE MODULUS OF THE MATERIAL I BULK ON THE TEMPERATURE OF AND PERCENTAGE VOIDS IN THE MIXTURE. MARKED ANISOTROPY OF THE MIXTURES WAS ALSO OBSERVED, THE ELASTIC MODULI IN THE PLANE OF SYMMETRY ORTHOGONAL TO THE DIRECTION OF COMPACTION, BEING SIGNIFICANTLY GREATER THAN IN THE AXIS OF SYMMETRY.

  • Corporate Authors:

    Nat Inst Road Research /S Africa

    ,    

    Cncl Scient & Indus Res /S Africa

    /Nat Inst Road Res
    ,   United States 
  • Authors:
    • Freeme, C R
  • Publication Date: 1971

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: 54 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00217409
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: TRIS, ATRI
  • Created Date: Sep 25 1972 12:00AM