This paper describes the microstructure characterization, strength, and durability of geopolymer mortar made by using low calcium fly ash (Class -F). Geopolymer mortars were prepared by using an alkaline solution (Sodium hydroxide (NH) and sodium silicate (NS)) with fly ash and sand. The fly ash to sand ratio is 1:1 with a constant rate of alkaline liquid /fly ash as 0.55 and NS/NH ratios as 1.5,2,2.5,3 Varying the ratio of NH concentrations as 2, 4, 6, 8M was prepared the geopolymer mortars for both the ambient and oven cured samples. The curing temperature of 60oC for 24 hours kept activating the geopolymerization. The results showed that the physical &Mechanical properties are increased and results in a good combination of eco-friendly material for cement compounds