Effect of fly ash/alkaline activator ratio and sodium silicate/NaoH ratio on fly ash geopolymer coating strength

Abstract

Fly ash geopolymer coating material potential used to protect surface used in exposure conditions. Ratio of fly ash/alkaline activator and Na₂SiO₃/NaOH play important parameter on determining the best flexural strength of geopolymer coating material. Fly ash and alkali activator (Al₂O₃/Na₂SiO₃) were mixed with the solids-to-liquid ratios in range of 1.0-3.0 and different ratios of Na₂SiO₃/NaOH (1.0-3.0) to prepare geopolymer coating material at constant NaOH concentration of 10 M. Effect of fly ash/alkaline activator ratio and Na₂SiO₃/NaOH on geopolymer coating was determined with respect to the highest flexural strength of the 1200oC sintering temperature of geopolymer coating substrates. The results concluded that the highest strength for fly ash geopolymer coating material is achieved 42 MPa when the solid/liquid ratio is 2.0 and the Na₂SiO₃/NaOH ratio is 2.5.