(Table in ) was reduced to the data with conditions similar to our experiments (i.e. dissolution of C 3 S in water or Ca(OH) 2 containing solutions at a w/s of 10 000). The effect of the three additives on the initial calcium activity -and the effect on the C 3 S dissolution rate -was thus further investigated by performing additional dissolution experiments where an initial amount of 6 mmol L -1 Ca(OH) 2 is added at the beginning of the experiment (Figure , Figure ). All three additives form calcium complexes in this system. Sodium citrate shows the highest ability to reduce the calcium activity (compare the values in the Ca 2+ activity column in Table ). The dissolution rate measured in these conditions increases in the presence of citrate -and succinate to a much lesser extent -and decreases in the presence of tartrate. When plotting the log of the initial dissolution rate as a function of the ion product ln(Π) (Figure ), the dissolution rate in the presence of 5 mmol L -1 of succinate and 6 mmol L -1 of Ca(OH) 2