Cement retarding mechanism of phosphonates and their interaction with aluminium

Abstract

Phosphonates are widely used components of retarder and dispersant formulations in concrete and mortar. In this study, 11 different phosphonate retarders were analyzed for their retarding performance in ordinary Portland cement (OPC) and alite. The interaction of the phosphonates with clinker phases was investigated using calorimetry and pore solution analysis in both the OPC and alite systems. Calorimetry, coupled with saturation indices calculated from the pore solution analysis, enables a better understanding of the retarding mechanism for phosphonate retarders in OPC and alite. The objective of this research is to provide improved design principles for retarding admixtures, allowing for the achievement of specific performance profiles.