Change in reaction kinetics of a Portland cement caused by a superplasticizer — Calculation of heat flow curves from XRD data

The hydration process of a commercial Portland cement was followed by means of heat flow calorimetry. The measured heat flow was compared with calculated heat flow curves based on XRD data. Examined in particular was the influence of one selected superplasticizer on the hydration of the Portland cement. It was shown that the superplasticizer in question retards both the aluminate reaction and the silicate reaction. It is certainly conceivable that there are more than only one explanation for the interaction between the superplasticizer and the cement. A complexation of Ca2 + ions from pore solution by the superplasticizer is as thinkable as the adsorption of the polymer on the nuclei or the anhydrous grain surfaces which in turn might lead to the prevention of the growth of the nuclei or the dissolution of the anhydrous grains.