Synergy between fly ash and limestone powder in ternary cements

The interaction between limestone powder and fly ash in ternary composite cement is investigated. Limestone powder interacts with the AFm and AFt hydration phases, leading to the formation of carboaluminates at the expense of monosulphate and thereby stabilizing the ettringite. The effect of limestone powder on OPC may be restricted due to the limited amount of aluminate hydrates formed by the hydration of OPC. The additional aluminates brought into the system by fly ash during its pozzolanic reaction amplify the mentioned effect of limestone powder. This synergistic effect between limestone powder and fly ash in ternary cements is confirmed in this study and it translates to improved mechanical properties that persist over time. (C) 2010 Elsevier Ltd. All rights reserved.