Effect of activators in different ratios on compressive strength of geopolymer concrete

Geopolymer concrete's workability and compressive strength were investigated by changing the ratio of alkali activators to each other ([Na.sub.2]Si[O.sub.3]/NaOH), the ratio of total solutions to fly ash, and the water content of aggregate. According to the findings, the saturated surface dry condition of the aggregate, in terms of water content in general, increases the workability and compressive strength. In addition, because of the reduction in the [Na.sub.2]Si[O.sub.3]/NaOH ratio, the concrete sets and solidifies faster, and the compressive strength and modulus of elasticity increase. Increasing the ratio of total solutions to fly ash prolongs the setting time but decreases the strength and elasticity modulus and increases the strain corresponding to the maximum stress. As a result, the strain corresponding to the maximum compressive strength of geopolymer concrete is higher, and the modulus of elasticity is lower than that of ordinary Portland cement concrete. Key words: geopolymer concrete, fly ash, mechanical properties, green concrete, alkaline activator
1. Introduction Portland cement concrete (ordinary Portland cement, OPC) is still a leading construction material due to its high strength, long service life, easy application, and low cost. Concrete production, [...]