Effects of polycarboxylate superplasticizers with different functional groups on the adsorption behavior and rheology of cement paste containing montmorillonite

The dispersing effectiveness of polycarboxylate superplasticizer (PCE) in cement paste is dramatically reduced as a result of the sorption of PCE by montmorillonite (MMT) clay. To improve the dispersing effectiveness of PCE in MMT-containing cement paste, three PCEswere synthesized by copolymerizing isopentenyl polyoxyethylene ether (TPEG) with trans-2-butenedioic acid (FA) (FA-TPEG), FA and methacryloxyethyltrimethyl ammonium chloride (FA-DMC-TPEG), FA and sodium p-styrene sulfonate (FA-SSS-TPEG), respectively. Their molecular structures were characterized by gel permeation chromatography, specific charge density , Fourier transform infrared spectrum, and ¹H nuclear magnetic resonance spectroscopy. X-ray diffraction and adsorption analysis were used to reveal the interactions between PCEs and MMT, and their dispersing performance in cement-MMT paste was evaluated using mini-cone and rheology measurements.. Results indicate that the difference in flowability caused by PCEs is primarily attributed to their different affinity for MMT in cement paste. Among them,, FA-SSS-TPEG showed excellent flowability due to its high affinity for cement particles and strong steric hindrance effect. © 2025 Informa UK Limited, trading as Taylor & Francis Group