Fig. 2
From: Carbonation of Portland Cement Studied by Diffuse Reflection Fourier Transform Infrared Spectroscopy
DR-FTIR spectra showing the effect of exposure to ambient air after selected time intervals for a unhydrated samples, and samples hydrated for b 10 min, c 30 min, d 4 h and e 8 h. The spectrum after 10 min of exposure within each hydration series was subtracted from all of the subsequent spectra to remove all signatures that are not the result of exposure. The assignments and characterizations of the peaks and bands, marked with I–X in the spectra, are presented in Table 1.