Application of Deflocculation Test to Characterise the Admixture Plasticizer and Superplasticizer Effect in Different Cements

A deflocculation test based on the method proposed by A. Verhasselt and J. Pairon has been applied to different mixes of cement-admixtures in order to distinguish quickly between plasticizer and superplasticizer. The admixtures used were commercial products containing different proportions of lignosulphonates (L), sulphonated naphthalene formaldehyde condensate (SNF) and sulfphonated melamine formaldehyde condensate (SMF). Three different cements were employed: a low tricalcium aluminate (C3A = 2.5%), a high alkali content (Na2O equivalent = 0.95%) and a high fineness portland cement (A.A. Blaine = 5002 cm2/gr). In addition, the minimum active dosage of superplasticizer was calculated. The influence of the type of cement in the minimum active dosage is clearly shown by the results obtained through this method.