THE VOID SPACING INDICATOR

INCREASED FROST RESISTANCE OF AIR-ENTRAINED CONCRETE IS LARGELY THE RESULT OF THE SIZE AND SPACING OF AIR VOIDS IN THE CEMENT PASTE. RESEARCH HAS INDICATED THAT FROST RESISTANCE OF CONCRETE IS GREATLY IMPROVED WHEN THE VALUE OF THE SPACING FACTOR IS ABOUT 0.008 INCHES OR LESS. THIS SPACING FACTOR MUST BE DETERMINED ON HARDENED CONCRETE AND REQUIRES THE USE OF ELABORATE EQUIPMENT INCLUDING A LINEAR TRANSVERSE DEVICE. A TEST METHOD AND A SIMPLE DEVICE SUITABLE FOR FIELD TESTING ARE DESCRIBED TO GIVE AN INDICATION OF THE SPACING FACTOR IN PLASTIC CONCRETE. THIS MAKES POSSIBLE THE IMMEDIATE DETECTION OF CONCRETES SUSCEPTIBLE TO EARLY FAILURE UNDER THE DISRUPTIVE FORCES CAUSED BY FREEZING AND THAWING. A SAMPLE OF MORTAR FROM THE FRESH CONCRETE IS IMMERSED IN A CLOSED CONTAINER COMPLETELY FILLED WITH DISTILLED WATER. AS THE MORTAR DISPERSES IN THE DISTILLED WATER, THE ENTRAINED AIR BUBBLES ARE RELEASED AND COLLECT AGAINST THE FLAT GLASS PLATE, AT THE TOP OF THE CONTAINER. BY EXPOSING THESE ENTRAINED AIR BUBBLES OF FRESH CONCRETE TO VISUAL OBSERVATION, THIS TEST PROVIDES A METHOD FOR APPROXIMATING THE SPACING FACTOR OF THE AIR VOID SYSTEM. DATA DEVELOPED IN THE STUDY ARE NOT SUFFICIENT TO FULLY EVALUATE THE VOID SPACING INDICATOR. HOWEVER, IT IS RECOMMENDED THAT IT SHOULD BE CORRELATED WITH DETERMINATION OF POWERS' SPACING FACTOR FOR THE PARTICULAR CONCRETE INVOLVED.

  • Supplemental Notes:
    • Res Rept 103-3, 10 PP, 11 FIG, 3 TAB, 6 REF, 2 APP
  • Corporate Authors:

    Texas Transportation Institute

    Texas A&M University System, 1600 E Lamar Boulevard
    Arlington, TX  United States  76011
  • Authors:
    • Torrans, P H
    • Ivey, D L
  • Publication Date: 1969-6

Subject/Index Terms

Filing Info

  • Accession Number: 00213816
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 28 1970 12:00AM