Rheological Properties of Fresh Cement Paste Modified by In Situ Polymerization of Acrylamide Monomer

Abstract

To explore the modification of rheological behavior of fresh cement paste by in situ polymerization, the rheological properties of fresh in situ polymerization modified cement (IPMC) pastes with various acrylamide (AM) monomer dosages and resting time were investigated by rheology test in this paper. The interaction mechanism between inorganic-organic components of IPMC paste and its influence on rheology are also discussed. The results revealed that the yield stress and plastic viscosity of fresh IPMC paste decreased as the AM dosage increased, and rose rapidly with the resting time when the AM dosage was more than 5%. The time-dependent rheological properties of IPMC paste were associated with various periods of AM polymerization reaction. This paper also found that the dispersing effect produced by the AM adsorption and the flocculating effect generated from the polyacrylamide (PAM) microgels bridging would jointly impact the structural buildup of IPMC paste; the former improved the rheological properties and fluidity, while the latter acted contrary. Our results provide the underlying insights needed to guide the dynamic regulation of rheological properties of cement-based materials by in situ polymerization modification.