Effect of alkali activator dosage on compressive and tensile strength of ground granulated blast furnace slag based geopolymer concrete
Use of Ordinary Portland cement contributes to environmental deterioration by releasing enormous quantity of CO2.To reduce use of cement, this research focuses on preparation of solely ground granulated blast furnace slag based geopolymer binder, activated by a combination of sodium hydroxide and sodium metasilicate cured under ambient temperature at 27°C. Engineering properties of geopolymer binder are evaluated and compared with conventional cement to assess its suitability as a binder for making geopolymer concrete. Compressive strength, flexure strength and split tensile strength are determined for geopolymer concrete. Microstructural analysis of geopolymer is performed by XRD, FTIR, FESEM and EDAX tests. The concentration of alkali activators is optimized by trials in laboratory and maximum compressive, flexural and split tensile strength of 44.07 MPa, 5.60 MPa and 4.39 MPa respectively, is obtained for geopolymer concrete at 2M concentration of sodium hydroxide solution with ratio of sodium metasilicate to sodium hydroxide taken as 2.0