EFFECT OF SUBSTITUTIONS OF FLYASH FOR PORTIONS OF CEMENT IN AIR-ENTRAINED CONCRETE

IT WAS INDICATED EARLIER THAT SUBSTITUTIONS OF FLYASH FOR UP TO 25 OR 30 PERCENT OF THE CEMENT IN AIR-ENTRAINED CONCRETE RESULTED IN: (1) INCREASE IN WATER-CEMENT RATIO, (2) DECREASE IN AIR CONTENT, (3) INCREASE IN STRENGTH OF MOIST CURED CONCRETE AT AGES BEYOND 28 DAYS, AND (4) DECREASE IN RESISTANCE OF THE CONCRETE TO FREEZING AND THAWING. THE EFFECT OF RESTORING THE AIR CONTENT OF THE CONCRETE CONTAINING THE FLYASH SUBSTITUTION BY ADDING AN AIR-ENGRAINING AGENT, NOT INCLUDED IN THE ORIGINAL PROGRAM, IS DESCRIBED. MATERIALS AND PROCEDURES IN THE SECOND SERIES OF TESTS WERE THE SAME AS IN THE FIRST, EXCEPT EXCEPT THAT THE AGGREGATES WERE FROM A DIFFERENT SOURCE AND THE MAXIMUM SIZE WAS REDUCED TO 3/4 IN. AND THE SIZE OF THE TEST BEAMS WAS REDUCED TO 3 BY 4 BY 16 IN. THE RESULTS SUBSTANTIATE THOSE OF THE FIRST SERIES OF TESTS AND INDICATE THAT IN MIXES WITH PROPORTIONS APPROXIMATING THOSE IN THIS TEST, RESTORING THE AIR CONTENT OF THE CONCRETE HAS THE FOLLOWING EFFECTS: (1) REDUCES THE STRENGTHS AT 7 AND 28 DAYS TO APPROXIMATELY THE SAME EXTENT AS THE CEMENT WAS REDUCED AT 1 YR. AND LATER; HOWEVER, THE STRENGTH IS EQUAL TO OR GREATER THAN THAT OF THE STANDARD CONCRETE; (2) IMPROVES THE RESISTANCE OF THE CONCRETE TO FREEZING AND THAWING TO A GREAT EXTENT BUT DOES NOT BRING IT UP TO THAT OF THE STANDARD CONCRETE; AND (3) REQUIRES CONSIDERABLY MORE AIR-ENTRAINING AGENT THAN NORMALLY MUST BE USED TO DEVELOP A LIKE AMOUNT OF AIR IN REGULAR CONCRETE MADE WITH NON-AIR-ENTRAINING CEMENT. /AUTHOR/

  • Supplemental Notes:
    • Vol 32, pp 328-335, 3 FIG, 6 TAB
  • Authors:
    • Larson, G H
    • Withey, N H
  • Publication Date: 1953

Media Info

  • Monograph Title: Proceedings of the Thirty-Second Annual Meeting of the Highway Research Board, Washington, D.C., January 13-16, 1953
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00213957
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 15 1971 12:00AM