The production of geopolymer concrete using GGBFS and nickel slag through ambient curing Available to Purchase

Concrete is the material mostly used for the construction of infrastructures in Indonesia. However, one of its main components, cement, has been discovered to be contributing 6% - 8% of global carbon dioxide (CO₂) emissions with further effects on global warming. There is, therefore, the need to produce environmentally friendly concrete which is known as geopolymer concrete using industrial wastes such as fly ash and slag instead of cement. Ground Granulated Blast Furnace Slag (GGBFS) and nickel slag are industrial solid wastes with high SiO₂ and Al₂O₃ content and this makes them suitable to be used as materials in geopolymer concrete through the activation of the chemical content by alkaline in the form of a mixture of NaOH and Na₂SiO₃. This study aimed to determine the effect of the mixture of GGBFS and nickel slag on compressive strength, split tensile strength, and workability of geopolymer with ambient curing. This involved using specimens developed with 75%, 50%, 25%, and 0% of GGBFS substitution against nickel slag while the ratio of Na₂SiO₃ to NaOH was 2:1 and the molarity used was 6M and 12M. Moreover, the superplasticizer Sika Viscocrete 8100 added to the concrete was 3% from the mass of the binders. The results showed the specimen with 75% GGBFS against nickel slag had the highest geopolymer concrete strength at 28 days as indicated by 44.95 MPa for compressive strength and 3.39 MPa for the split tensile strength at 6M while the values were 57.72 MPa and 4.23 MPa respectively for 12M.