Effect of Treated Sago Pith Waste Ash and Silica Fume to the Mechanical Properties of Fly Ash-Based Geopolymer Brick

摘要

The excessive use of ordinary portland cement in construction always being the issue on the environment. The use of waste materials in replacement of ordinary portland cement in concrete structures is one of the solutions to increase the sustainability elements in the construction world. Therefore, this paper investigates the effect of partial replacement of fly ash with sago pith waste and silica fume ashes in fabricating the geopolymer mortar concrete. The mixtures of geopolymer mortar concrete were prepared by replacing sago pith waste and silica fume ashes at 5% of total weight of fly ash. There were six specimens of geopolymer mortar cubes and bricks fabricated in this study. The specimens then tested with compressive strength test, rebound hammer test and ultrasonic pulse velocity test. The results from the tests compared with some existing published works to see the effect of replacing the fly ash with sago waste and silica fume ashes on the strength of concrete. Comparisons had been made and concluded that the molarity of alkaline solution, Al3O_2 and CaO influenced the development of compressive strength along the curing time of fly ash based geopolymer concrete. The 14M molarity of alkaline used in 5% silica fume in fly ash based geopolymer produced higher compressive strength than using the 10M molarity. Among the waste material used in replacement of cement, silica fume was the best waste material to increase the compressive strength. Meanwhile, the other waste materials included the sago waste reduced the compressive strength of the concrete samples.