Summer Research Fellowship Programme of India's Science Academies

Saturation point of different Cements and Superplasticizers determined by Marsh Cone and study of Rheological Parameters


National Institute of Technology, Andhra Pradesh


Professor, Indian Institute of Technology, Hyderabad


The workability of concrete plays an important role in the placing of concrete in moulds. Various superplasticizers can be added to concrete at the time of mixing, to impart workability. But the optimum dosage of superplasticizer has to be added to the concrete mix to prevent loss of fluidity, segregation, bleeding, air entrainment etc. Finding the optimum dosage of superplasticizer corresponding to different cements is a challenging task due to the possible incompatibility between the cement and admixtures. Once the appropriate dosage of superplasticizer is determined in mortar mixtures, it can later be adjusted in concrete mix trials. In this study, three different brands of locally available Ordinary Portland Cements and three different commercially available superplasticizers, all belonging to Polycarboxylic Eher (PCE) family, are used to understand the incompatibility between various cements and superplasticizers and establish their saturation points. This report presents the results of an experimental study performed on various cement pastes to define the saturation dosage of a superplasticizer required for each type of cement. Water/Cement ratio of 0.4 was used for all the mixes and the saturation point corresponding to each cement and superplasticizer combination was determined using Marsh Cone. Rheological tests were then performed on the cement paste for different dosages of superplasticizer and the yield stresses obtained are compared with the Marsh Cone flow time.

Keywords: marsh cone, superplasticizer, saturation dosage, rheology, incompatibility

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