Mechanistic study of the improvement of LC3 rheological properties by PCE superplasticizers- A comparative study with OPC system

Recently, LC3 attracts more and more attentions due to low CO2 emission. Understanding the mechanisms of PCEs on LC3 rheology is crucial for advancing its application. This study investigates the rheological properties of LC3 and ordinary Portland cement (OPC) in response to PCE superplasticizers. HPEG PCEs were successfully synthesized via free radical copolymerization with varying acrylic acid (AA) to macromonomer (MM) ratios, and their quality were characterized using Gel Permeation Chromatography (GPC). Fluidity tests and rheology measurements revealed that PCEs enhance fluidity and reduce dynamic yield stress and plastic viscosity in both systems, although LC3 requires a higher PCE dosage than OPC. At the same time PCEs in OPC improves with increasing AA:MM ratios, whereas in LC3, the optimal ratio was found to be medium. The total organic carbon and PCE anionic charge amount measurements were applied to discover the mechanisms. Clacined clay consumed a large amount of PCE which was not contributing to dispersion due to its high specific surface area rather than surface charge. Furthermore, the performance of PCEs in the LC3 system is governed by the synergistic effect of their anionicity and side chain density. These findings provide insights into the distinct mechanisms of PCEs in LC3 compared to OPC, offering a theoretical basis for developing tailored PCEs for LC3 applications.