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.