CONCRETE IN TERMS OF RELATIVE HUMIDITY CONCRETE IN TERS OF RELATIVE HUMIDITY

WHEN HARDENED CONCRETE IS EXPOSED TO THE AIR, ITS MOISTURE CONTENT TENDS TO ATTAIN A STATE OF EQUILIBRIUM WITH THE RELATIVE HUMIDITY OF THE AIR. CHANGES IN MOISTURE CONTENT ARE IMPORTANT IN VARIOUS WAYS, AND IT IS OFTEN DESIRABLE TO HAVE DEFINITE INFORMATION ON THE MOISTURE CONDITION OF THE HARDENED CONCRETE IN BLOCK, WALLS, FLOORS, OR OTHER BUILDING MEMBERS. A RAPID METHOD AND SIMPLE APPARATUS FOR DETERMINING THE MOISTURE CONDITION OF HARDENED CONCRETE BLOCK IS DESCRIBED AND THE RESULTS ARE EXPRESSED IN TERMS OF RELATIVE HUMIDITY. THE PROCEDURE IS BASED ON EXTENSIVE STUDIES TO DEVELOP THE PROPER APPARATUS AND CALIBRATION AND TESTING TECHNIQUES FOR MAKING THIS METHOD AS PRACTICABLE AND DEPENDABLE AS POSSIBLE. AS A RESULT, THIS METHOD GIVES RELIABLE INDICATIONS OF THE MOISTURE CONDITION OF CONCRETE BLOCK IN ABOUT 15 TO 30 MIN (IF THE BLOCK IS BROKEN INTO SMALL PIECES WITH A HAMMER BEFORE TESTING) AND USUALLY WITH 20 MIN. THIS IS LESS THAN 1 PERCENT OF THE 48 TO 72 HR NEEDED TO SATURATE AND THEN OVEN-DRY BLOCK TO CONSTANT WEIGHT AS REQUIRED BY PRESENT SPECIFICATIONS FOR TESTS OF MOISTURE CONTENT AND ABSORPTION. WITH SLIGHT MODIFICATIONS, THE RELATIVE HUMIDITY METHOD CAN BE USED TO DETERMINE THE MOISTURE CONDITION OF HARDENED CONCRETE AT THE SURFACE AND INTERIOR OF LARGE SPECIMENS SUCH AS WALL AND FLOOR SLABS. IT CAN ALSO BE USED TO DETERMINE THE MOISTURE CONDITION OF OTHER CONSTRUCTION MATERIALS AND ASSEMBLIES AFFECTED BY RELATIVE HUMIDITY. /AUTHOR/

  • Supplemental Notes:
    • Vol 55, pp 1085-1109, 10 FIG, 1 TAB, 16 REF, 2 APP
  • Corporate Authors:

    American Mining Congress

    Ring Building, 1200 18th Street, NW
    Washington, DC  United States  20036

    American Society for Testing and Materials

    100 Barr Harbor Drive, P.O. Box C700
    West Conshohocken, PA  United States  19428-2957
  • Authors:
    • Manzel, C A
  • Publication Date: 1955

Media Info

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Subject/Index Terms

Filing Info

  • Accession Number: 00213888
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 1 1971 12:00AM