Fig. (9) Compressive strength of fly ash based geopolymer mortar versus H2O/Na2O molar ratio according to curing time for A/B=1.0 with incorporation of: (a) 10% calcium hydroxide; (b) 10%Portland cement; and (c) 5%Portland cement; (d) 10%Metakaolin hydroxide; (e) 20%Metakaolin.