Also, the content of calcium silicate hydrate (CSH) formed in GBFS-NC9 (G) blend is greater than that formed in GBFS activated by sodium hydroxide (I). The morphology of CSH formed in GBFS-NC9 blend differed from that formed in case of GBFS activated by sodium hydroxide. This is mainly due to different Ca2+/Si4+ ratio. Calcium carbonate distributed along hardened paste of GBFS-NC19 was observed. The open pores (P) that appeared in case of GBFS-NC19 are due to the higher CC/SH ratio which reduces the aluminosilicate content leading to a decrease in geopolymerization and pozzolanic reaction rates and, therefore, decreases the compressive strength and increases the water absorption. The dense and compact microstructure of GBFS-NC9 as a result of relatively lower CC/SH ratio in dry activator (NC9) of mix G which leads to the dissolution of activated species (Al3+,Si4+and Ca2+) is sufficient for the formation of geopolymer and hydrated product (CSH), thus, producing a very compact structure.