Effect of waste glass powder as a partial precursor in ambient cured alkali activated fly ash and fly ash-GGBFS mortars

This study investigated the feasibility of using waste glass powder (GP) as a partial precursor in fly ash (FA) and ground granulated blast furnace slag (GGBFS) based alkali activated mortars cured at ambient condition. FA was replaced by 0%-40% GP to produce alkali activated FA and FA-GGBFS mortars. The experimental results showed that the use of GP reduced workability of both FA and FA-GGBFS mortars. While no strength increase was observed by use of GP in the FA mortars, 5%-11% increase of compressive strength was noted in the FA-GGBFS mortars by the use of 10%-20% GP as a replacement of FA. Similarly, porosity, sorptivity and chloride permeability decreased significantly by 10%-20% GP in the FA-GGBFS mortars. However, drying shrinkage of both FA and FA-GGBFS mortars increased with the increase of GP content. Microstructural investigations showed that the use of GP significantly improved the microstructure of FA-GGBFS mortars by increasing the calcium containing reaction products such as calcium aluminosilicate hydrate (C-A-S-H) and calcium silicate hydrate (C-S-H) gel.