A User Friendly Geopolymer Concrete Mix Design Procedure

Cast-in-situ is concrete is one of the preferred types of concrete construction, which is poured into the moulds to cast concrete of desired shape. India being one of the populous countries of the world, most of the cast-in-situ concrete is handled by semi-skilled labors on the site. Thus, safety of the worker is one of the prime concerns. However, most of the mix design methodology proposed for making geopolymer concrete heavily rely on the use of highly concentrated sodium hydroxide for obtaining desired strength, which is unsafe to handle. Therefore, a user-friendly mix design methodology to produce geopolymer concrete using sodium silicate (SS) as alkali reagent and ground granulated blast furnace slag (GGBS) as the binder solid is proposed. The proposed mix design methodology also evaluates the correlation between the SS/GGBS ratio and the 28 day compressive strength for developing a rational mix design. Mix design for SS/GGBS ratios of 0.35 to 0.65 is proposed in the present paper. It was found that a strength in the range of 40 to 66 N/mm2 can be produced at the end of 28 days curing period. An example explaining the step wise process of the mix design methodology has been given in this paper.