VARIATIONS IN WATER REQUIREMENT OF INDUSTRIALLY PRODUCED PORTLAND CEMENTS

The purpose of this study was to determine the reason for the variation in water requirements of ordinary portland cements. Pastes from a variety of industrially produced ordinary portland cements were examined to correlate their water requirement with the variation in chemical composition and particle size distribution. The standard Vicat procedure for determination of water requirement was used. Statistical analysis complemented by laboratory experiments showed that the water requirement increases with an increasing wt. percent of particles in the 10-30 micrometer range, with increasing C3A content, and with increasing alkali content of the cement. The tendency to false set also affects the water requirement of cement. Blaine values do not significantly correlate with the water requirment of ordinary portland cements in the range of 2800-4000 sq cm/g.