Investigation of Water-Reducing Admixtures for Concrete.

Varying amounts of 13 chemical water-reducing admixtures were tested in pastes, mortars, and concrete to determine their performance characteristics and compliance with a proposed specification. Results showed that a all of the admixtures tested in concrete and most of those tested in mortars and pastes permitted some water reduction b time of setting of the paste and mortar was not unduly lengthened by addition of any of the admixtures c the 28- and 90-day compressive strengths of the mortars in which admixtures were used approximated those of the mortars tested without admixtures d most of the admixtures acted also as air-entraining agents, reducing the amount of such agents required to produce the desired air content in the concrete e use of a water-reducing admixture in concrete containing fly ash slightly improved physical properties of the concrete and f the admixtures tested for compliance with the proposed specification met all the tentative requirements. Author