VIBRATION, SEGREGATION, AND SEGREGABILITY OF CONCRETES

RESULTS OF TESTS, OBSERVATIONS, AND RESEARCH DURING THE PERIOD 1966-1969 ARE CONSOLIDATED. THE FOLLOWING CONCLUSIONS ARE DRAWN: WHEN JOB CONCRETE IS VIBRATED, AS IS GENERALLY THE CASE, THE CONTROL SPECIMENS SHOULD ALSO BE VIBRATED, IN A MANNER TO OBTAIN CONSOLIDATION EQUIVALENT TO THAT IN THE WORK. AN APPROXIMATE FORMULA IS DERIVED THAT APPLIES TO THE VIBRATION OF SPECIMENS AND OF JOB CONCRETE. TABLE VIBRATION, IN SPITE OF APPEARANCES, IS MORE DIFFICULT TO STANDARDIZE THAN INTERNAL VIBRATION WITH A POKER, WHICH BESIDES HAS LESS SEGREGATION AND DISPERSION. THE INFLUENCE OF DURATION OF VIBRATION IS VERY IMPORTANT FOR SHORT TIMES; CONSOLIDATION, AT FIRST RAPID, TENDS LATER TO APPROACH A FINAL VALUE ASYMPTOTICALLY. FOR DENSE AND PLASTIC CONCRETE CONSOLIDATON BY RODDING IS INSUFFICIENT, BUT FOR SOFT CONCRETES CONSOLIDATION BY VIBRATION IS NOT BETTER THAN RODDING AND THE RISK OF SEGREGATION INCREASES. THE INFLUENCE OF FREQUENCY AND PRESSURE (FOR AIR-OPERATED VIBRATORS) IS RELATIVELY WEAK FOR SUFFICIENTLY LONG TIMES. THE CURVES OF SEVERAL OF THE FIGURES PERMIT EASY STANDARDIZATION OF THE INTERNAL VIBRATION OF SPECIMENS. EXTRAPOLATION OF THE FORMULAS CORRESPONDING TO THESE CURVES LEADS, IN GENERAL, TO A POWERFUL VIBRATION ON THE JOB. WHERE EFFECTIVE CONSOLIDATION IS NOT FEASIBLE, VERY DENSE CONCRETE SHOULD BE AVOIDED FOR ONE CAN GET POORER RESULTS THAN WITH SOFTER CONCRETES SIMPLY RODDED. THIS STUDY AND THE FORMULAS DEVELOPED PERMIT EVALUATION, MEASUREMENT, AND CALCULATION OF THE INTERNAL VIBRATION OF TEST SPECIMENS IN CORRELATION WITH THE JOB CONCRETE AS A FUNCTION OF THE ESSENTIAL PARAMETERS. /AUTHOR/

  • Supplemental Notes:
    • 15 Pp, 13 FIG, TABS
  • Corporate Authors:

    American Concrete Institute

    Aci Headquarters Translation
    ,   USA 
  • Authors:
    • Dreux, G
    • Gorisse, F
  • Publication Date: 1971-3

Subject/Index Terms

Filing Info

  • Accession Number: 00213988
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 1 1971 12:00AM