Effect of Alkaline Activators on the Mechanical Properties of Geopolymer Mortar

Abstract

"Geopolymerization is a process where silica and alumina rich source materials turn into excellent binding materials by the aid of alkali solutions. Materials such as fly ash are by-products in energy power plants. Fly ash is classified based on its constituent materials. Fly ash class F mainly consists of alumina and silica. Compressive strength of class F fly ash geopolymer mortar is influenced by many factors such as fluid to binder ratio, Na2SiO3/NaOH ratio, curing duration, curing temperatures and molarity of the activator solution. The present study investigates the effect of the fluid to binder ratio and Na2SiO3/NaOH ratio on the compressive strength of geopolymer mortar. The curing temperature was fixed to 80 °C. The curing durations investigated was 24h. For each combination, three cubes with dimensions of 50 x 50 x 50 mm were casted. After heat curing in the laboratory oven, the samples were tested on a universal testing machine for the compressive strength. The results showed very high early compressive strength of 66.39 MPa for samples cured at 80 °C and for a duration of 24 hr. The significance of the present study is that it will allow for establishing methods for production of high strength geopolymer mortar that can be used in civil engineering applications, in addition to the environmental advantages of using such source materials to produce binding materials with outstanding mechanical properties."