Compatibility between Polycarboxylate Ether with Different Charge Densities and Cement

Abstract

Polycarboxylate ether (PCE) of different charge densities has been synthesized via free radical polymerization. The molecular structure is characterized by gel permeation chromatography (GPC) and proton nuclear magnetic resonance (H1 NMR). The interaction between PCE and three different-C3A-content cements has been systematically studied. The results of rheological properties, specifically apparent viscosity and yield stress, demonstrate that there are two cement paste loss stages in cement hydration process. This theory could provide guidance for the design of PCE with slump retention ability. By matching PCE release rate with the cement hydration process, we could ensure a cement paste with smooth and steady slump retention. PCE with moderate charge density shows the best compatibility with cement owing to the smallest differences in adsorption amount in different cements. Moreover, the influence of PCE on the early-age properties of cement paste confirms that the interaction of PCE with C3A or its hydration products determines the compatibility between PCE and cement, especially in the first cement paste loss stage.