Interactions between polymeric dispersants and calcium silicate hydrates

To better understand the mechanism of interaction between hydrating silicat e-based cements and polymeric dispersants of the type used as "superplastic izers'' in modern construction concretes, two different types of polymeric dispersant were added (at concentrations of 1 and 10 g/L) during the synthe sis of calcium silicate hydrate (C-S-H) via the "pozzolanic reaction" in di lute slurries of lime and reactive silica, at Ca/Si ratios in the range of 0.66-1.50, Although both polymers gave degrees of adsorption of >79% in all cases studied, no significant structural modifications of the resulting C- S-R products were observed via X-ray diffraction or Si-29 magic angle spinn ing-nuclear magnetic resonance, These results differ from recent work in wh ich it was shown that similar types of polymer could intercalate into the i nterlayers of C-S-H that was made using an alternative process, IL is sugge sted that the process by which the C-S-H is formed may have a strong influe nce on whether C-S-H can intercalate polymers, This observation is relevant to understanding the fate of such polymers in concrete.