Study on the Effect of Fly Ash in Geopolymer Cement

The utilization of by-product and solid waste of the industry in attempt as a replacement for the ordinary Portland cement (OPC) have been rapidly researched and investigated in recent years. The resultant product, also known as geopolymer cement, proves to be of significantly better than the OPC in various aspects. The quest for finding a replacement binder was mainly triggered by the great consumption of raw materials and disturbingly high emmision of CO2 in the production of OPC. Hence, the use of fly ash in geopolymer cement is duely investigated to find a more efficient binder in the casing annulus. Fly ash based geopolymer are environment friendly and are expected to solve many problems of disposing these by-products of coal at various landfills in the World. Fly ash is also much more resistant than OPC against chemical or acidic reaction and fire, have longer durability, higher pumpability and cost effective. This paper will present the work carried out to study the effect of fly ash in geopolymer cement. Fly ash is rich in alumina and silica, thus when dissolved in alkaline solution form an aluminosilicate gel that binds the elements together to form a good geopolymer cement. Fly ash is mixed with the alkaline solution, preferably NaOH, and Na2SiO3 solution to form a geopolymer paste, before which several tests done to investigate its advantages. Fly ash based geopolymer cement is an excellent alternative to OPC, with proven advantages.