Abstract
The chemistry of the early reactions that occur during the hydration of the phases in portland cement concrete are considered. Desirable concrete properties are gained because of hydration of the cement. If pozzolanic or latent hydraulic admixtures are present, additional hydration reactions will contribute to strength development. The rate and products of cement hydration may be influenced by the presence of these or of chemical admixtures. Although emphasis is placed on portland cement concrete, reactions in other cements are briefly discussed. This paper appears in transportation research board record no. 1284, Cement, admixtures, and concrete 1990.