Optimum Mix Design and Structural Behaviour of Steel Fibre Reinforced Geopolymer Concrete Cured Under Ambient Condition

Concrete is one of the most common construction materials in the world. The primary material used in the production of concrete is cement. However, the manufacture of cement is associated with greenhouse gas emissions which cause global warming. Hence, there is a need to develop other types of concrete that does not contain cement in order to maintain environmental sustainability. Geopolymer concrete as green concrete without cement has been investigated as a viable alternative to traditional concrete for reducing the adverse environmental impact. Fly ash (FA) and ground granulated blast furnace slag (GGBS) are the most popular industrial by-product materials used in the production of geopolymer concrete with the presence of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) as alkaline activator solutions. The development of geopolymer concrete requires a suitable mix design that will meet the required compressive strength and have the desired workability. The Taguchi method has been used to design the optimum mix proportions for geopolymer concrete with GGBS as the source of aluminosilicate under ambient curing conditions. The influence of binder content, alkaline activator to binder content ratio, sodium silicate to sodium hydroxide ratio, and sodium hydroxide concentration on the geopolymer concrete has been investigated. It was found that specimens with a binder content of 450 kg/m3, an alkaline activator to binder content ratio of 0.35, a sodium silicate to sodium hydroxide ratio of 2.5, and sodium hydroxide concentration of 14 M produced the highest compressive strength. However, the setting time was found to be short. Hence, FA was used as partial replacement of GGBS in different proportions to increase the setting time...