Both sucrose and etidronic acid are known to strongly retard the silicate reaction of ordinary Portland cement (OPC). Sucrose is the strongest retarder of the three molecule classes (compare Figure and). This can be recognized by comparing the peak maximum of the respective heat flows or the onset of the acceleration period. The dosages are color-coded in Figure . To directly compare the effect of a retarder amount of 3 µmol g -1 , the red curves in each diagram need to be compared.