Use of Portland PFA cement in combination with superplasticizing admixtures

The results of a test programme undertaken to achieve parity between concretes made with Portland cement (PC, Class 42.5 N) to BS 12 and Portland pulverized-fuel ash cement (PPFAC) to BS 6588 at equivalent cement content, by controlling the water content of the mix and the use of a superplasticizing admixture are described. With 27% PFA as a constituent of the cement, parity at 28 days was achieved at water contents of between 145 and 160 kg/m(3), depending on the cement content. A mix design chart is developed from the data to illustrate how the water and PPFAC contents of concrete can be adjusted to achieve a particular design strength. Issues relating to practical aspects of use are also considered. (C) 1998 Elsevier Science Ltd.