ADMIXTURES IN CONCRETE

AN ADMIXTURE IS ANY MATERIAL OTHER THAN WATER, AGGREGATES, AND HYDRAULIC CEMENT THAT IS USED AS AN INGREDIENT OF A CONCRETE OR MORTAR MIXTURE AND ADDED TO THE BATCH IMMEDIATELY BEFORE OR DURING MIXING. FOUR TYPES OF ADMIXTURES ARE DISCUSSED: (1) ACCELERATORS, THE MOST COMMON OF WHICH IS CALCIUM CHLORIDE; (2) AIR-ENTRAINING, TO PROTECT THE CONCRETE AGAINST THE DAMAGE IT MAY SUFFER IF THE PASTE BECOMES SATURATED WITH WATER AND THEN FREEZES; (3) RETARDERS AND WATER REDUCERS, WHICH EXTEND SETTING TIME 30 TO 50 PERCENT TO COMPENSATE FOR PLACEMENT TEMPERATURES, TO AVOID COLD JOINTS, OR TO AVOID UNDESIRABLE EFFECTS OF DISPLACEMENTS AND DEFLECTIONS; AND (4) POZZOLANS, WHICH REACT WITH HYDROXIDES TO FORM COMPOUNDS WITH CEMENTITIOUS PROPERTIES, AND USUALLY PRODUCE A LOWER COST CONCRETE.

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Subject/Index Terms

Filing Info

  • Accession Number: 00213986
  • Record Type: Publication
  • Files: TRIS, TRB, ATRI
  • Created Date: Aug 8 1971 12:00AM