Synthesis of polycarboxylate superplasticiser modified by self-made functional monomer for improving clay tolerance

Polycarboxylate superplasticisers (PCEs) are commonly sensitive to clay minerals. In this work, several clay-resistant PCEs (CR-PCEs) were synthesised using a novel self-made functional monomer (FM). The FM and the resulting superplasticisers were characterised by Fourier transform infrared spectrophotometry and gel permeation chromatography. The results showed that the CR-PCEs exhibited better dispersion performance than conventional PCE (C-PCE) in cement pastes containing montmorillonite (Mmt). The adsorption amount of the CR-PCEs on the Mmt was investigated using ultraviolet–visible spectrophotometry and it was found that the CR-PCEs had a lower clay sensitivity than the C-PCE. X-ray diffraction results of the Mmt revealed that the interlayer spacing of the Mmt treated with the CR-PCEs was lower than that of the Mmt treated with the C-PCE. It was thus concluded that the developed FM effectively improved the clay tolerance of the PCE.