PHYSICAL ASPECTS OF THE SETTING OF PORTLAND CEMENT CONCRETE

IN THIS PAPER THE TERM "SETTING PERIOD" DENOTES THE FIRST STAGE OF CHANGES IN THE CEMENT: WATER MIXTURE, DURING WHICH THE PROCESSES OF CHANGE ARE ACCELERATING. THE SETTING PROPERTIES DISCUSSED ARE (1) PENETRATION DEPTH OF THE VICAT NEEDLE IN CEMENT PASTE, (II) STANDARD PROCTOR PENETRATION RESISTANCE OF MORTAR SCREENED FROM CONCRETE, (III) SLUMP, (IV) PULSE VELOCITY, AND (V) ELECTRICAL RESISTANCE OF CONCRETE. IT IS SUGGESTED THAT THE CHANGE OF ALL THESE PROPERTIES CAN BE APPROXIMATED WITHIN THE USUAL INITIAL SET-FINAL SET LIMITS BY THE POWER FUNCTION Y = AT TO THE ITH POWER, WHERE Y = A PHYSICAL SETTING CHARACTERISTIC OF THE CEMENT PASTE, MORTAR, OR CONCRETE, SUCH AS THE PENETRATION RESISTANCE; T = TIME ELAPSED SINCE MIXING; AND A AND I ARE EMPIRICAL PARAMETERS. ANALYSES OF EXPERIMENTAL DATA INDICATE THE SIGNIFICANT POINT THAT FOR A GIVEN TEST METHOD THE POWER I IS INDEPENDENT OF THE COMPOSITION OF THE MIXTURE WITHIN WIDE LIMITS EXCEPT FOR THE PRESENCE OF CERTAIN ADMIXTURES. THE USE OF THE POWER FUNCTION IS SIMPLE BECAUSE, FOR MIXTURES WHERE I IS CONSTANT, IT PROVIDES A FAMILY OF PARALLEL STRAIGHT LINES IN A LOG Y VERSUS LOG T SYSTEM. FOR A GIVEN TEST METHOD THE POSITIONS OF THESE LINES, OR THE A AND I PARAMETERS, PROVIDE MEANINGFUL INFORMATION ABOUT THE SETTING PROCESS. /ASTM/

  • Supplemental Notes:
    • Vol 6, No 1, PP 150-162, 8 FIG, 29 REF
  • Corporate Authors:

    American Society for Testing and Materials

    100 Barr Harbor Drive, P.O. Box C700
    West Conshohocken, PA  United States  19428-2957
  • Authors:
    • Popovics, S
  • Publication Date: 1971-3

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Filing Info

  • Accession Number: 00214005
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 3 1971 12:00AM