Effect of solid-to-liquid ratios on metakaolin geopolymers

Abstract

This present work investigates the effect of the solid-to-liquid (S/L) ratio on the preparation of metakaolin geopolymer. Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) were used as alkaline activator with a constant NaOH concentration of 10 M and Na2SiO3/NaOH ratio of 1.0. Different values of S/L ratio of 0.6, 0.7, 0.8, 0.9 and 1.0 were used. The products obtained were characterized after 28 days of ageing. The evaluation techniques in this study were compressive strength, microstructural analysis and phase analysis. The highest compressive strength was 32 MPa achieved with S/L of 0.8. Microstructure showed a dense geopolymer matrix at the highest strength. In addition, phase analysis showed the featureless amorphous hump at S/L ratio of 0.8 and 1.0 which indicate the high compressive strength achieved at this ratio.