Setting time and 7-day strength of geopolymer mortar with various binders

•Setting time, 7-day compressive strength, 7-day flexural strength were evaluated.•Effect of curing temperature, NaOH molarity on 7-day strength were studied.•Increasing GGBS content in the mixture leads to decrease setting time.•Increasing curing temperature and molarity improves compressive and flexural strength.•Binder type has a significant effect on 7-day strength, setting time and microstructure.•Addition of GGBS and silica fume achieves better properties compared to fly ash only. Concrete is considered one of the most vital materials used in construction all over the world which ordinary portland cement (OPC) is used as the binder to produce it. The harmful effect of OPC production on environment is well known. Therefore, geopolymer concrete is considered an important alternative material in construction field due to its acceptable mechanical and durability properties as well as being environmentallyfriendly product. The main objective of this study is to investigate setting time and 7-day properties of geopolymer mortar considering several parameters as curing temperature, sodium hydroxide solution molarity, alkaline solution to binder ratio and binder type. The evaluated properties in this study were setting time, 7- day compressive strength, 7- day flexural strength and microstructure of mortar specimens. Results indicated that binder type has a significant effect on the mentioned properties. Mixes contained 50% fly ash, 35% ground granulated slag (GGBS) and 15% silica fume yield the best properties. Also increasing curing temperature, sodium hydroxide solution molarity and decreasing alkaline solution to binder ratio improved mechanical properties of geopolymer mortar with various binders.