Engineering properties of slag-based geopolymer concrete

Geopolymer concrete is manufactured from high-volume waste materials, such as fly ash from coal-burning power stations and can be altered by adding mineral admixtures, such as ground granulated slag or granulated lead smelter slag. The addition of these admixtures may lead to increase the compressive strength of fly ash, or reduce the amount of cementitious material in the binder, which in turn reduces costs and offers further environmental benefits. This paper presents an experimental study on the behavior of slag-based geopolymer concrete. The experimental program included 25 mix designs which were used to examine several parameters. The key parameters considered were the slag-to-fly ash ratio, slag-to-river sand ratio, alkaline solution-to-binder ratio and curing method. The mechanical properties were tested, analyzed and compared to the American Concrete Institute and Australian Standards set for ordinary Portland cement concrete in order to determine the similarities and differences. The results show that using partially slag as a binder of up to 75% can provide a normal concrete strength. The results concluded that the mechanical properties of the slag-based geopolymer concrete were similar to that of fly ash-based geopolymer concrete.