A SUGGESTION FOR TESTING THE ECONOMIC SELECTION OF AIR- ENTRAINING CONCRETE ADMIXTURES /IN GERMAN/

IN ORDER TO INCREASE THE FROST RESISTANCE OF CONCRETE, SYNTHETIC AIR-VOIDS ARE INTRODUCED BY MEANS OF FOAMING AGENTS, THESE CREATE SUFFICIENT POROSITY AND THEREFORE ALLOW WATER IN THE CEMENT TO EXPAND IF IT FREEZES. IN ORDER TO ESTABLISH MINIMUM COSTS FOR ADMIXTURES AND CEMENT REQUIREMENT WHILE RETAINING THE SAME STRENGTH, EQUIVALENT MIXTURES MUST BE PREPARED FROM SELECTION OF ADMIXTURES OFFERED. DURING EXTENSIVE DEVELOPMENT OF CONCRETE FOR A POWER-STATION IN AUSTRIA THE AUTHOR REPEATED THESE TIME- CONSUMING AND EXPENSIVE TRIAL MIXTURES TO ATTAIN A CERTAIN AIR-VOID CONTENT, AND INTRODUCED A NEW METHOD OF DETERMINING THE MOST ECONOMICAL ADMIXTURE. IN THIS METHOD EQUAL AIR CONTENT IS PRODUCED FICTITIOUSLY, INDEPENDENT OF THE VOIDS MEASURED, IN THAT THE MISSING OR SURPLUS AIR IS REPLACED BY IMAGINARY WATER, THUS CORRESPONDINGLY CORRECTING THE WATER- CEMENT RATIO. FOR THIS, IT IS REQUIRED THAT ALL THE MIXTURES TO BE COMPARED HAVE THE SAME STRENGTH. THE COMPOSITION OF THE CONCRETE WHICH IS NECESSARY TO ATTAIN UNIFORM STRENGTH WITH ANY ADMIXTURE IS DETERMINED BY INTERPOLATION BETWEEN TWO MIXTURES. THE PLANNING AND EXECUTION OF THE TEST, THE EVALUATION OF THE TEST RESULTS AND THE NECESSARY CALCULATIONS ARE EXPLAINED. /FG/RRL/

  • Supplemental Notes:
    • Vol 9, No 9, PP 640-649, 6 PHOT, 6 REF
  • Authors:
    • Roth, H
  • Publication Date: 1967-9

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Filing Info

  • Accession Number: 00212832
  • Record Type: Publication
  • Source Agency: Road Research Laboratory /UK
  • Files: TRIS
  • Created Date: May 13 1970 12:00AM