Portland cement has been used in oil well cement during drilling operation. It has numerous disadvantages related to operational failure at high thermal well and environmental hazards during production and manufacturing of Portland cement. Geopolymer cement (GPC) is an organic aluminosilicate binder which possess high compressive strength. Geopolymer examined as a prospective material to replace Portland cement due to high compressive strength and durability. This study presents an investigation to evaluate the feasibility of fly ash of the Thar power plant as a substitute for Portland cement. Thirty samples of geopolymer were designed by varying the concentration of alkaline activators. The effect of sodium silicate, sodium hydroxide and their concentration ratio in fly ash was determined through compressive strength measurement at varied curing time and temperature. The experimental results of XRF analysis revealed that fly ash of Thar power plant contains high calcium oxide and classified as Class C type. Furthermore, the study exposed that alkali activators have a promising influence on fly ash. Geopolymer compressive strength was increased by increasing sodium silicate and sodium hydroxide concentration. Moreover, the designed geopolymer cement showed high compressive strength and enhanced by increasing the curing time and temperature. Based on the experimental result, it is revealed that geopolymer exhibited superior thermal resistance and mechanical properties as compared to the class G cement. Fly ash of the Thar power plant can be use as an alternate of OPC with the addition of other additives that further enhance the properties of geopolymer.

Keywords: Fly ash, Compressive strength, Sodium hydroxide, Sodium silicate. Cementing