Effect of sea sand and recycled aggregate replacement on fly ash/slag-based geopolymer concrete

Abstract The purpose of this study is to investigate the impact recycled aggregate (RA) and sea sand (SS) replacement on fly ash (FA) slag-based geopolymer concrete (GPC). An orthogonal array design employed obtain optimum mix proportions, mixes are prepared using slag percentages 10%, 20%, 30% in FA/slag-based GPC. Sodium hydroxide (NaOH) solution at three concentrations (8 mol/L, 12 16 mol/L). mechanical properties determined based tensile strength, compressive flexural elastic modulus. GPC water-binder ratios 0.3, 0.4, 0.5 0%, 25%, 50%, 75%, 100% RA replacement. results showed that variation ratio had little effect strength modulus (SS–GPC), but it a significant river (RS–GPC). also noticeable change damage surface specimens. In addition, SS hinders hydration reaction early stage reduces GPC; however, later stages, becomes insignificant.