A new composite cementitious material for construction

This study was conducted to explore a suitable method for activating a high calcium fly ash with an alkali sulphate rich fly ash. A successful mechano-chemical activation of fly ashes in a cement free system was achieved through individual grinding and blending. Sulphate activation by alkali sulphate rich fly ash as well as the activity of waste gypsum as grinding aid for providing more reactive particles was revealed. The hydration product of the new ternary blended composite cementitious material was found to be very stable with high calcium content and low Ca/Si ratio. The non-expansive nature of secondary ettringite formation was also identified after a period of 180 days.