Effect of superplasticizers with different anchor groups on the properties of cementitious systems

We herein reported a series of superplasticizers that were synthesized from the macro-monomer polyethylene glycol methacrylate and the monomers acrylic acid, sodium allyl sulfonate, or vinylphosphonic acid at different molar ratios. In order to explore the influence of COO-, SO32-, and PO32- on the performance of superplasticizers, fluidity tests and plastic viscosity tests were carried out to evaluate the dispersion performance of these polymers. Furthermore, the conformation of these superplasticizers in calcium hydroxide solution was analyzed via dynamic light scattering and Ca2+ concentration tests. The results showed that these superplasticizers exhibited the best dispersion effect when the molar ratio of COO-:SO32- and COO-:PO32- was 3:1. In addition, the calcium complexing capacity of the phosphonate groups was higher than that of the sulfonate ions, leading to the lower plastic viscosity of cement pastes containing the superplasticizer with COO-:PO32- at a ratio of 3:1. This study provides valuable information for the application in practical engineering. [Display omitted]