Influence of NaOH-concentration and blast-furnace-slag on the properties of geopolymer mortars

The paper focused of the production of geopolymer materials using solid wastes, including fly ash, bottom ash (BA), granulated blast furnace slag (GBFS) in thermal power plants, and granulated blast furnace slag. Using the BA and GBFS as source material for geopolymer mortar is cost-effective, it allows safe disposal of the postproduction industrial wastes and improves properties of mortar for green buildings approach and development. In the present investigation, BA and GBFS were used as alumino-silicate materials for making alkali-activated bottom ash mortar (GPM). The effects of NaOH content in the sodium hydroxide solution with the concentration of 10-16 M and the presence of granulated blast furnace slag content (0-60 %) on the workability and the compressive strength development of alkali-activated bottom ash mortar were studied. The absolute volume method combined with the experimental results was used to determine the compositions of GPM specimens. Furthermore, the compressive strength of the mortar samples was performed following ASTM C109 and Vietnamese Standard TCVN 6016:2011. The results revealed that both NaOH concentration and granulated blast furnace slag content greatly affected the workability of mixtures and compressive strength development of the tested samples. Moreover, the relationship between the 28-day compressive strength and a water-to-geopolymer solid ratio of GPM specimens is also determined in this work.