PROPERTIES OF CEMENTS AND CONCRETES CONTAINING FLY ASH

RESULTS OF TESTS ARE PRESENTED, WHICH WERE CONDUCTED TO DETERMINE THE EFFECT OF USING FLY ASH AS A REPLACEMENT FOR PORTLAND CEMENT IN MORTARS AND CONCRETES. FLY ASHES FROM FIFTEEN DIFFERENT SOURCES AND PORTLAND CEMENTS OF SEVEN COMPOSITIONS WERE TESTED. FLY ASHES IN PERCENTAGES UP TO 50 WERE BLENDED WITH THE PORTLAND CEMENTS. VARIABLES INVESTIGATED INCLUDED CHEMICAL COMPOSITION AND FINENESS OF FLY ASH AND OF PORTLAND CEMENT. RESULTANT PROPERTIES INVESTIGATED INCLUDED STRENGTH, ELASTICITY, VOLUME CHANGE, DURABILITY AS INDICATED BY RESISTANCE TO FREEZING AND THAWING AND BY RESISTANCE TO THE ACTION OF SODIUM SULFATE, PLASTIC FLOW, AND HEAT OF HYDRATION. RESULTS INDICATE THAT FLY ASHES OF MODERATELY LOW CARBON CONTENT AND MODERATELY HIGH FINENESS EXHIBIT A HIGH DEGREE OF POZZOLANIC ACTIVITY AS COMPARED WITH MOST NATURAL POZZOLANS. WHEN THESE FLY ASHES ARE USED IN MODERATE PERCENTAGES AS A REPLACEMENT FOR PORTLAND CEMENT, THERE CAN BE PRODUCED CONCRETES WHICH EXHIBIT QUALITIES EQUAL AND IN SOME RESPECTS SUPERIOR TO THOSE EXHIBITED BY CONCRETES CONTAINING CORRESPONDING PORTLAND CEMENT WITHOUT FLY ASH. CONCRETES CONTAINING PROPERLY CONSTITUTED FLY-ASH CEMENTS WHEN COMPARED WITH CONCRETES CONTAINING PORTLAND CEMENTS EXHIBIT: (1) ABOUT THE SAME WATER REQUIREMENT TO PRODUCE A GIVEN CONSISTENCY, (2) SOMEWHAT LOWER COMPRESSIVE STRENGTH AT EARLY AGES BUT SUBSTANTIALLY HIGHER COMPRESSIVE STRENGTH AT LATER AGES UNDER NORMAL CONDITIONS OF MOIST CURING, (3) COMPRESSIVE STRENGTHS WHICH ARE SUBSTANTIALLY HIGHER AT EARLY AGES WHEN CURED AT HIGHER TEMPERATURES, (4) SHRINKAGE WHICH IS LIKELY TO BE NO MORE AND MAY BE LESS, (5) LOWER HEAT OF HYDRATION, (6) ABOUT THE SAME OR SOMEWHAT LESS RESISTANCE OF FREEZING AND THAWING, AND (7) GREATER RESISTANCE TO SULFATE ACTION. THE PERFORMANCE OF FLY-ASH CEMENTS APPEARS TO BE MOST SATISFACTORY WHEN THE PORTLAND-CEMENT CONSTITUENT IS OF NORMAL FINENESS AND OF NORMAL OR HIGH-LIME COMPOSITION. IT IS CONCLUDED THAT FLY ASHES OF MODERATELY LOW CARBON CONTENT AND MODERATELY HIGH FINENESS MAY BE EMPLOYED AS REPLACEMENTS FOR PORTLAND CEMENT IN PERCENTAGES UP TO 30 IN ORDINARY CONSTRUCTION WITHOUT IMPAIRING THE QUALITIES OF CONCRETE. FOR HEAVY CONSTRUCTION IT APPEARS THAT FLY ASHES MAY BE EMPLOYED AS REPLACEMENTS FOR PORTLAND CEMENTS IN PERCENTAGES AS HIGH AS 50, WITH THE ADVANTAGES OF SUBSTANTIALLY LOWER TEMPERATURE RISE DUE TO HYDRATION OF THE CEMENT AND OF HIGHER ULTIMATE COMPRESSIVE STRENGTH.

  • Supplemental Notes:
    • Vol 33, pp 577-612
  • Authors:
    • Davis, R E
    • CARLSON, R W
    • Roy, W
    • Kelly, J W
    • DAVIS, H E
  • Publication Date: 1937-5

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  • Accession Number: 00212706
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 3 1994 12:00AM