Published online by Cambridge University Press: 25 February 2011
The course of the initial set reactions of Portland cement-PFA blends is markedly influenced by the presence of fly ash. Data are presented on the effect of two Class F PFA materials blended with cement in 30:70 ratio. Selected analyses of the aqueous phase compositions at lh to 336h are presented. During the first 6h a nearly steady state aqueous phase composition is achieved with respect to Na, K and Ca concentrations. Following a renewed burst of hydration activity, Ca decreases rapidly in the interval 6–24 h while Na and K contents rise more gradually.