Activation of blended cements containing fly ash

This study has investigated the activation of reactivity of fly ash in different blended cements such as lime-fly ash, lime-fly ash-stag and Portland fly ash cements. Experimental results have indicated that the addition of Na2SO4 can significantly increase the strength of all these blended cements. The activation effect happens mainly during the first 3 to 7 days. The grinding of fly ash also increases its activity, but is not as effective as the addition of Na2SO4. On the other hand, the combination of grinding and the addition of Na2SO4 shows a much higher strength than a single activation method. Finally, this paper also discusses the feasibility of the addition of Na2SO4 in different cement and concrete products production processes. (C) 2001 Elsevier Science Ltd. All rights reserved.