The structure becomes more denser at 28 days [14, 7]. Fig.5 shows the micrographs of samples containing 10% SCBA at 7 days and 28 days of curing. In the micrographs only C-S-H is appeared and that hexagonal Ca(OH)2 crystals are not appeared. This shows SCBA being an efficient pozzolanic material as a consequence of its high silica content.