shows that the slope of the heat flow curve is steeper for sucrose compared to etidronic acid at a given retardation time. This is also visually apparent in the heat flow curves (Figure ). However, the quantitative analysis reveals that the slope of the sucrosecontaining samples is steeper than the slope of the etidronic acid-containing samples by a factor of approximately 2 for the larger retardation times, i.e., t m > 30 h. This reflects the behavior of Qmax as a function of t max (Figure ). The acceleration of the rate of C-S-H formation is slower for etidronic acid compared to sucrose at comparable overall retardation. This can be interpreted as a consequence of the different retardation mech-