A NEW METHOD OF EVALUATING THE SHAPE OF GRAINS, SOME RESULTS OF APPLICATION

EIN NEUES VERFAHREN ZUR BEWERTUNG DER KORNFORM UND EINIGE ERGEBNISSE SEINER ANWENDUNG

DETAILS ARE GIVEN OF A NEW METHOD WHICH USES AS PARAMETER CHARACTERIZING THE SHAPE OF THE GRAINS THE VOIDS RATIO OF THE AGGREGATE MIXTURE WHICH HAS BEEN COMPACTED NOT UP TO FAILURE POINT UNDER GIVEN CONDITIONS. THIS NEW PARAMETER ENABLES A QUANTITATIVE RELATION BETWEEN THE SHAPE OF THE GRAINS AND IMPACT STRENGTH TO BE ESTABLISHED. IT ALSO SHOWES THE GREAT SENSITIVITY OF THE IMPACT STRENGTH TO SMALL VARIATIONS IN THE SHAPE OF THE GRAINS: THIS EXPLAINS THE DIFFICULTIES ENCOUNTERED DURING THE CALIBRATION OF IMPACT STRENGTH MEASURING APPARATUS. THESE DIFFICULTIES COULD PROBABLY BE SOLVED IF IMPACT STRENGTH INDICES DETERMINED BY MEANS OF REGRESSION CURVES WERE CONVERTED INTO THE CORRESPONDING REFERENCE VOIDS RATIO AND STANDARD GRAIN SHAPE. IN THE FUTURE, REGRESSION CURVES WILL BE DETERMINED. PRESENT REFERENCE GRADING CURVES ARE INSUFFICIENT AS THEY DO NOT TAKE INTO ACCOUNT THE EFFECTS OF THE DIFFERENT GRAIN SHAPES. TESTS CARRIED OUT ON AN ASPHALTIC CONCRETE SHOW THAT THE VOIDS RATIO, THE BULK DENSITY AND STABILITY OF BITUMINOUS MIXTURES DO NOT DEPEND ON THE SHAPE OF THE GRANS. HOWEVER THE SHAPE OF THE GRAINS PLAYS AN IMPORTANT ROLE IN THE WEAR AND SLIPPERINESS OF THE MIXTURES. THE USE OF FLAT AGGREGATES INCREASES THE BRAKING DISTANCE BY 10%. /TRRL/

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    Verlag fuer Publizataet

    Auf der heide 20
    300 Isernhagen HB, Hannover,   Germany 
  • Authors:
    • Patzold, V
  • Publication Date: 0

Language

  • German

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 737-43
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00081696
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Feb 27 1975 12:00AM