What Is Fourier Transformation Infrared Spectra Of Formed Composites
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3.2. FT-IR examinations.
Fourier transformation infrared spectra of formed composites have many identified bands which are: stretching vibration of O-H bond at about 3430, 1600 cm-1, stretching vibration of CO2 located at about 1410 cm-1, asymmetric stretching vibration at about 1110 cm-1 corresponding to S-O4 stretching mode (ν3) and out-of plane bending mode (ν4) of ettringite [Mollah et al. (1998); Hanna et al. (1995)] asymmetric stretching vibration (T–O–Si) at about 975 cm-1 where T = Si or Al, symmetric stretching vibration of CO2 at about 870 cm-1, symmetric stretching vibration (Si–O–Si) in the region 676-700 cm-1 and bending vibration (Si–O–Si and O–Si–O) in the region of 430-445 cm-1 [Panias et al. (2007); Alexandre et al.…show more content… (2012)].
The immersion effect at 6 and 12 month using various ratios of EAFS as illustrated in FTIR spectra Figures (5, 6). The patterns of 6 months [Fig. (5)] show an increased in broadness of T-O-Si band at about 975 cm-1 with EAF slag increase up to 50 % in addition to low wave number shift which depicts vitreous component increase. The increased intensity of the Si–O–(Si, Al) asymmetric band in addition to the shift to higher wave number (from 690 to 779 cm-1) with increased contents of EAFS up to 50 % (A3), suggests aluminosilicate framework modification as compared with solely GGBFS based geopolymers as a consequence of cation substitution in the non-framework sites [Bernal, et al. (2012)]. However, a sharp increase in asymmetric stretching vibration at about 1110 cm-1 corresponding to ettringite [Mollah et al. (1998); Hanna et al. (1995)], upon using 75 % EAFS reflecting the decreased content of the amorphous geopolymer resulting from the increased iron content resulting in lower stability against sulfate attack as reflected from ettringite formation, the increased intensity of carbonate bands at 1430 cm-1 (ν C–O ), and 867 cm-1(δ C–O ) with EAFS as a result of the carbonates in the used raw material which inactive under alkaline activation [Bernal, et al. (2012)].
Further increase in the immersion time (12M) led to extra ettringite increase upon using 75 % EAFS. A continuous increase in the main asymmetric band of the