Effect of crosslinked polycarboxylate superplasticizers with varied structures on cement dispersion performance

Abstract

In order to investigate the effect of double bond content in the crosslinkers on the performance of superplasticizers, three different crosslinked polycarboxylate superplasticizers were synthesized herein with various respective crosslinkers. Their impacts on the fluidity, absorption, and hydration behavior of cement systems were studied. The results showed that the polymer, which was synthesized using a crosslinker with four double bonds and five/six double bonds, had higher fluidity and the highest fluidity reached up to 395 mm at W/C of 0.35. Additionally, thermogravimetric analysis and hydration heat tests showed that the crosslinked polycarboxylate superplasticizers could prolong the hydration process of cement slurries. Among these three kinds of crosslinked polycarboxylate superplasticizers, the induction period of cement slurry containing the polymer with crosslinker of four double bonds was significantly extended to facilitate the processing of the concrete. The purpose of this study is to provide strategies for studying high-performance polycarboxylate superplasticizers with novel topological structure.

Advances in Organic Rheology-Modifiers (Chemical Admixtures) and Their Effects on the Rheological Properties of Cement-Based Materials

“…At a fixed molecular weight, the surface-occupied area became smaller for star-shaped PCEs with an increase in arm numbers, resulting in an increase in the adsorption free energy. In addition, many papers have reported cross-linked PCEs with different cross-linking monomers [142][143][144][145][146][147] with varied numbers of double bonds. Some reports have shown that slight cross-linking can improve the adsorption and thus the initial flowability of cement paste.…”

Reconfiguring Molecular Conformation from Comb-Type to Y-Type for Improving Dispersion Performance of Polycarboxylate Superplasticizers

“…Hyperbranched PCEs were first introduced and prepared by Hamada in 2006 and subsequently received a great deal of research attention. Then, hyperbranched PCEs with different structures have been synthesized successively. − Ran et al synthesized the main chain dendritic hyperbranched PCEs via in situ redox polymerization, which had compact structures and increased the thickness of the adsorption layer. However, more adsorption was needed to cover the same surface area of cement particles, showing poor dispersion ability for cement .…”