The Interaction of Methylene Blue Dye with Calcium-Silicate-Hydrate

The interaction of methylene blue (MB) dye solution with various calcium-silicate-hydrate (C-S-H) preparations (C/S ratio=0.60-1.80) was investigated. Experiments were also performed by treating the C-S-H in lime-saturated water and distilled water. The effects of MB on the X-ray basal spacing and the degree of polymerization were determined using low-angle X-ray diffraction (XRD) and (29)Si MAS NMR spectroscopy. An interaction mechanism for C-S-H-MB using a "bridging" model for the C-S-H nanostructure is proposed. The model is consistent with the XRD and (29)Si MAS NMR results.