The Effect of Fly Ash and Alkali Activator Mass Ratio (FA/AA) and Curing Conditions on the Mechanical Properties of High Compressive Strength Geopolymer Mortar

Abstract

Cement production is not an environmentally friendly process, as it consumes a lot of energy. One of the cement production processes is the sintering of calcareous and clay materials which is responsible for CO₂ emissions into the atmosphere. Globally, Cement production is associated with excessive carbon dioxide emissions. Geopolymer is an environmentally friendly alternative to replace Portland cement. Geopolymer is synthesized by a chemical reaction (geopolymerization) between aluminosilicate materials (industrial by-products, such as blast furnace slag or fly ash) and alkali activators. Fly ash is an aluminosilicate material from coal combustion residue that can be used as a geopolymer material to make more environmentally friendly mortar. Geopolymer mortar with FA/AA variations with a FA/AA variation range of 1.75-3.25 has an optimal compressive strength, namely at a ratio of 2.75 with a value of 57.6 Mpa. Oven curing for 48 hours is the optimum value with a value of 56.2 MPa and the highest compressive strength value was obtained at curing at a temperature of 140℃, namely 55.2 MPa.