Effect of Curing Time and Variations in Na2SiO3: NaOH Ratio on the Mechanical Properties of Fly Ash-based Geopolymer Artificial Aggregates using the Crushing Method

Abstract

Burning coal to produce electrical energy in PLTU produces waste in the form of fly ash. This waste must be managed properly so that it does not cause detrimental environmental effects. Fly ash has potential as a building material because it contains silica, aluminum, and other oxides that can react with alkaline solutions to form geopolymer compounds. Geopolymer has good mechanical properties and is resistant to acidic and alkaline environments. The development of the crushing method for aggregate materials, artificial geopolymers, and fly ash is an interesting work direction because it can utilize fly ash waste and reduce the dependence on aggregates. Moreover, this material can be used to help reduce the effects of development construction on the environment. The crushing method is utilized to obtain geopolymer artificial aggregate with the desired size. Aggregates can be destroyed to become small particles by using destruction techniques and mechanical crushing tools, such as hammer mills, jaw crushers, and ball mills. The aggregate impact value (AIV) percentage reaches 13.20% at a Na₂SiO₃/NaOH ratio of 2, but it decreases to 12.64% at a Na₂SiO₃/NaOH ratio of 3.5. The AIV percentage reaches 12.82% without the addition of sand, but it decreases to 12.64% when the added amount of sand is 20%. The AIV percentage increases to 12.76% when the added sand is 40%. Moreover, the AIV percentage reaches 12.64% after curing for 24 hours, decreases to 12.46% after 48 hours of curing, and increases to 12.94% after 72 hours of curing.