Compatibility between hpeg type pces with various anionic charge densities and portland cements with different c3a contents

Abstract

This study focused on the compatibility of phosphate and sulfonate-substituted polycarboxylate ether-based water-reducing admixtures (PCE) exhibiting different anionic charge densities with Portland cements having different C3A contents. For this purpose, the effects of synthesized PCEs on the fresh, rheological, and hardened state properties of the paste and mortar mixtures were investigated. According to the results, anionic charge density greatly affected the performance of PCE. In terms of the investigated parameters, the best performance was obtained with a high anionic charge density PCE containing 5% sulfonate anionic group. It was also observed that the positive effect of increasing the charge density of the phosphate anionic group was less efficient compared to the other studied PCEs. In addition, the effectiveness of anionic charge density was found to be largely PCE dosage dependent. Increasing the cement C3A content to 9% caused cement-PCE incompatibility. In addition, the PCE anionic charge density change had variable effects on the paste and mortar mixtures in terms of fresh state and rheological properties.