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 Ca
2+
/Si
4+
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