Compressive strength of mortars incorporating alkali-activated materials as partial or full replacement of cement.

• Fly ash, silica fume, rice husk ash, GGBS and metakaolin were incorporated in mortars. • Cement content was minimized in geopolymer mortars by 80 to 100% by using alkali-activated GGBS. • Compressive strength was improved by activating FA and GGBS with AS of NaOH and Na 2 SiO 3 with AS/ binder ratio = 0.25 in mortars. • The proposed AS of NaOH and Na 2 SiO 3 failed to activate each of silica fume, rice husk ash and metakaolin. Cement industry is one of the industries that contribute to global warming by emitting tons of carbon dioxide. On the other hand, there are lots of industrial wastes that are piling up daily. Therefore, minimizing the use of cement and reducing its negative impact on the environment is our scope. This paper targets to study the effect of alkali-activated pozzolanic materials used as partial or full substitution of cement in mortars cured at ambient temperature. Fly ash, silica fume, rice husk ash, metakaolin, as well as ground granulated blast-furnace slag were incorporated in mortars as cement substitute by ratios varied from 10% to 100% by weight of cement. Alkaline solution of sodium hydroxide and sodium silicate was utilized as activator with activation solution to binder ratio varies from 0.25 to 0.5. Besides, the ratio of sodium silicate to sodium hydroxide was kept 2:1 throughout the study. The results showed the potential of producing high early strength eco-friendly mortars using alkali-activated fly ash and slag as cement substitutions with ratios of 80% and 100% respectively, which is promising for sustainable construction. [ABSTRACT FROM AUTHOR]