Transmission Electron Microscopy of Hydrated Dicalcium Silicate Thin Films

A method of preparing calcium silicate hydration products for transmission electron microscopy is presented. Thin films of dicalcium silicate are evaporated onto substrates and hydrated in a vacuum chamber. Since the resulting hydration products are undisturbed, the interrelations of the species can be studied. The technique provides specimens suitable for high-resolution microscopy. This method produces hydration products like those reported when conventional specimen preparation techniques are used. Calcium silicate hydrate gel, two forms of C-S-H II (fans and fiber bundles), afwillite, and Ca(OH)₂ morphologies were observed. Coevaporated CaCl₂ additions improve the electron diffraction patterns obtained from the C-S-H II fan structures but increase shrinkage of these structures on drying.