There are many commercially important multiphase materials which contain amorphous phases, such as cement
pastes, porcelains, glass-ceramics or pharmaceutical compounds. However, the analysis of amorphous phase(s)
within cement matrices that contain high amounts of crystalline phase(s) is a challenge. Here, we report measurements
of total scattering data quantitatively analyzed by Pair Distribution Function (PDF) minimization
and Rietveld methodology to determine phase compositions including both amorphous and nanocrystalline
phase contents in cement-related samples. Furthermore, laboratory techniques were used to complement the
sample characterization. In addition to five reference materials, the main phase of calcium aluminate cements,
CaAl2O4 hydrated at 50 °C to yield crystalline hydrogarnet, Ca3Al2(OH)12, (43wt%) and nanocrystalline aluminum
hydroxide gel, Al(OH)3·0.1H2O (50wt%) was also investigated. The PDF analyses revealed that the hydroxide gel
has a gibbsite local structurewith an average particle size close to 5nm. PDF and Rietveld quantitative phase analysis
results fully agree.
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