The current study proposes fabricating the practical alkali-activated material (AAM) by adjusting the sodium hydroxide characteristics and dosage of low calcium Class F fly ash as slag substitution. The effects of Na2O with three concentration of 3, 4, and 6 mass.% of total solid fraction and slag replacement with Class F fly ash at three various percentages of 10, 30, and 50 mass.% on the engineering properties in terms of slump flow, setting times, and compressive strength of the AAM pastes have been explored. Experimental results showed that effect of the Na2O concentration was opposite to that of the Class F fly ash increment on the properties of the AAM pastes. The increased concentration of Na2O induced the resultant AAM pastes with lower flowability, shorter setting times, and higher compressive strengths at all ages of curing. The dosages of Na2O concentration and slag replacement with low calcium Class F fly ash should be respectively limited at lower than 6 mass.% and 10 mass.% for fabricating the AAMs with desired engineering properties.