To assess the C-S-H formation, 1 L of solution containing 5 g of
Ca(OH)2 and 5 g of the samples (silica fume, quartz, and SCBA) were
prepared and kept sealed at 60 C for 7 days. After this period, each
solution was filtered, the residue was dried in vacuum to avoid
carbonation, and the X-ray diffraction and Fourier transform
infrared spectroscopy (FTIR) analyses were conducted. FTIR was
performed using the Nicolet 6700 machine, Thermo Scientific.
Samples were mixed with KBr in the ratio of 1:100 (sample/KBr).
The direct transmission (DT) technique was used. The scans took
place between 4000 and 600 cm1 and at a resolution of 4 cm1.