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Abstract: A study was carried out, using heat flow calorimetry and quantitative X-ray diffractometry, of the different influences which are exerted by types of cationic Polydiallyldimethylammonium (PDADMA) displaying different anionic counterions on the hydration behavior of an Ordinary Portland Cement (OPC). It was shown that the influence of the cationic polymer PDADMA on the hydration of the cement will tend to be strongly dependent on the nature of the anionic counterion. In case of OH−, more calcium sulfate will tend to be dissolved in the early stages, which acts in turn as an accelerator for the hydration of the C3S phase. In case of there will tend to occur a secondary gypsum precipitation, which will in turn act to lower the Ca2+ – content in the mix water, leading to a retardation of the hydration process compared to the hydration in absence of polymer. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]