ACI 212.3R-04

This report updates the previous 1991 report. Chemical Admixtures, which are primarily water-soluble substances, are discussed. Finely divided mineral admixtures are dealt with by ACI Committees 232, Fly Ash and Natural Pozzolans in Concrete, and 234, Silica Fume in Concrete. For the purpose of this report, chemical admixtures are classified into five groups: air-entraining; accelerating; water-reducing and set-controlling; admixtures for flowing concrete; and miscellaneous. Admixtures possessing properties identifiable with more than one group are discussed with the group that describes its most important effect on concrete.