Chemical structures and adsorptive behaviors of superplasticizers on β-C₂S

Abstract

The chemical structures of four types of superplasticizers (SPs) and their adsorptive behaviors on β-C₂S were investigated. The adsorption properties of SPs on β-C₂S were measured and the relationship between the adsorption quantity and the specific surface of β-C₂S was analyzed. The experimental results show that the adsorption quantity increases with the surface area increase of β-C₂S, but the adsorption quantity per surface area is similar, which means that the main adsorbent is β-C₂S itself. Polycarboxylic ester (PCE) showed the highest adsorption amount on β-C₂S, followed by β-naphthalene sulfonates (NSF) and formaldehyde-acetone condensates sulfonates (FAS), amino sulphonate (AS) showed the least adsorption amount on β-C₂S. PCE affected the surface potential of β-C₂S particles in water differently in comparison with other types of SPs. The adsorption capacity of SPs on β-C₂S is determined by factors such as molecular structure, functional groups and molecular weight of SPs.

Keywords

β-dicalcium silicate / superplasticizer / adsorption / ζ-potential / PCE

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