N.A. Farhan, M.N. Sheikh, M.N.S. Hadi
University of Wollongong,
Keywords: geopolymer, Taguchi method, compressive strength, setting time
Summary:In this paper, the Taguchi method has been used to design optimum mix proportion for geopolymer concrete produced with ground granulated blast furnace slag (GGBFS) as aluminosilicate source. The influences of binder content, alkaline activator to binder content (AL/Bi) ratio, sodium hydroxide (NaOH) concentration, and sodium silicate to sodium hydroxide (SS/NaOH) ratio were investigated in the design of optimum mix proportion. A total of nine mix designs were evaluated. It was found that specimens with alkaline activator of 450 kg/m3, AL/Bi ratio of 0.35, SS/NaOH ratio of 2.5, and NaOH concentration of 14M produced the highest compressive strength (60.38±MPa) on the 7th day. However, the setting time was found to be short. Hence, fly ash (FA), metakaolin (MK), and silica fume (SF) were blended with GGBFS in different proportions to increase the setting time. It was found that the setting time improved for the partial replacement of GGBFS with FA, MK, and SF.