DETERMINATION OF A POLY HYDROXY CARBOXYLIC ACID RETARDER IN HARDENED CONCRETE

THE SODIUM SALT OF A POLY HYDROXY CARBOXYLIC ACID HAS FOUND WIDESPREAD USE AS A SET RETARDER. PROBLEMS HAVE BEEN ENCOUNTERED WITH EXCESSIVE OR INSUFFICIENT USE OF RETARDER. IN VIEW OF THE WIDE USE OF THIS PARTICULAR RETARDER, THE VARYING EFFECTIVE RETARDERS WITH RESPECT TO DIFFERENT CEMENTS, AND IN ORDER TO RESOLVE SUSPECTED CASES OF ERRONEOUS DOSAGE, A METHOD WAS DEVELOPED FOR DETERMINATION OF THIS POLY HYDROXY CARBOXYLIC ACID RETARDER IN HARDENED CONCRETE. AN INTENSIVE STUDY WAS CONDUCTED WITH REFERENCE SAMPLES TO FIND THE OPTIMUM MEANS OF SAMPLE PREPARATION, RETARDER EXTRACTION, REAGENT STABILIZATION, COLOR DEVELOPMENT, AND COLOR MEASUREMENT. A RELIABLE COLORIMETRIC METHOD FOR DETERMINING A POLY HYDROXY CARBOXYLIC ACID RETARDER IN HARDENED CONCRETE CONTAINING LIMESTONE, GRAVEL, OR SLAG AGGREGATE WAS DEVELOPED. RESULTS WERE NOT SIGNIFICANTLY DIFFERENT WHEN CONCRETES VARYING IN AGE FROM TIME OF FINAL SET TO ONE YEAR WERE ANALYZED. ANY DETERMINATION OF THIS RETARDER IN HARDENED CONCRETE MUST BE BASED ON A CALIBRATION STEP USING CONCRETE CONTAINING KNOWN AMOUNTS OF RETARDER AND COMPOSED OF THE SAME INGREDIENTS AND MIX PROPORTIONS AS THE CONCRETE TO BE ANALYZED. DETERMINATION OF THE AMOUNT OF THE RETARDER STUDIED WOULD DETECT BOTH OVER DOSES AND OMISSION OF RETARDER. OVER DOSAGE CAUSES PROLONGED RETARDATION OF SET, WHILE OMISSION OF SOME OR ALL OF THE SPECIFIED AMOUNTS OF RETARDER WOULD RESULT IN UNEXPECTED SETTING OF THE CONCRETE DURING FINISHING.

  • Supplemental Notes:
    • Vol 8, No 3, PP 14-18, 2 FIG, 4 TAB, 3 PHOT, 6 REF
  • Authors:
    • Frederick, W L
    • Ellis, J T
  • Publication Date: 1968-3

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  • Accession Number: 00212560
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 13 1994 12:00AM