Effect of polycarboxylate-based water-reducing admixture chains length on portland cement-admixture compatibility.

This study investigated, the effect of polycarboxylate-based water-reducing admixture (PCE) molecule chain length modification on the cementadmixture compatibility. Seven PCEs with varying chain lengths were synthesized for this aim. Paste and mortar mixtures were prepared by combining a high C₃A (9.1%) CEM I-42.5 R-type cement with PCEs. The Marsh-funnel flow time, mini-flow, dynamic yield shear stress, final viscosity and setting times of the paste mixtures were analyzed. The PCE requirement for target flow, the time-dependent flow performance, and compressive strength of mortar mixtures were studied. In this way, effects of the change in only the main chain length, only the side chain length, and both main and side chain lengths of PCE molecule on the Portland cement-admixture compatibility were comparatively researched. Consequently, the PCE with medium main and side chain lengths exhibited the best performance and was the most compatible with high C₃A cement in terms of the examined properties. The effect of PCE chain length change on cement-admixture compatibility was investigated. PCE with medium main and side chain lengths was the most compatible with high C3A cement. After a certain point increase in chain length led to incompatibility. Water/cement ratio and PCE dosage affect the PCE-cement compatibility. [ABSTRACT FROM AUTHOR]