PERMEABILITY OF GAP-GRADED VERSUS CONTINUOUSLY-GRADED CONCRETE

THE PERMEABILITY TESTS WERE PERFORMED BY FORCING WATER THROUGH CONCRETE SPECIMENS OF 5 3/4-IN. LONG BY 6-IN. IN DIAMETER UNDER A PRESSURE OF 400 PSI AND BY MEASURING THE RATE OF PERCOLATION. THE PERMEABILITY COEFFICIENTS ARE OBTAINED FOR GAP-GRADED AND CONTINUOUSLY-GRADED CONCRETES HAVING THE SAME MAXIMUM SIZE OF COARSE AGGREGATE, IDENTICAL CEMENT CONTENT, AND APPROXIMATELY EQUAL WORKABILITY. THE TEST RESULTS INDICATE THAT COEFFICIENT-OF-PERMEABILITY VALUES RANGE FROM 0 TO 0.000033 FOR BOTH GAP-GRADED AND CONTINUOUSLY-GRADED CONCRETES. THEY ARE THEREFORE ESSENTIALLY IMPERMEABLE AS COMPARED WITH AN AVERAGE VALUE OF 0.0015 FOR GOOD QUALITY CONCRETE. HOWEVER, THE COMPARISON OF THE INFLOW-TIME CURVES INDICATED THAT GAP-GRADED CONCRETE APPEARS LESS PERMEABLE THAN CONTINUOUSLY-GRADED CONCRETE FOR EQUAL CEMENT CONTENT AND MAXIMUM SIZE OF COARSE AGGREGATE. THE GAP-GRADED CONCRETE HAD SLIGHTLY LESS WATER-CEMENT RATIO AND HIGHER COMPRESSIVE STRENGTH. /AUTHOR/

  • Supplemental Notes:
    • Tech Rept NO 7, 642 (68)
  • Corporate Authors:

    South Dakota School of Mines and Technology, Rapid City

    501 East St Joseph Street
    Rapid City, SD  USA  57701

    South Dakota Department of Transportation

    700 East Broadway Avenue
    Pierre, SD  USA  57501

    Bureau of Public Roads /US

    400 7th Street, SW
    Washington, DC  USA  20590
  • Authors:
    • Li, S T
    • Ramakrishnan, V
  • Publication Date: 1970-5

Subject/Index Terms

Filing Info

  • Accession Number: 00212082
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Files: TRIS, STATEDOT
  • Created Date: Jul 27 1970 12:00AM