The Effect of Curing Temperature on the Early Age Properties of Granulated Furnace Slag Based Reactive Geopolymer Concrete

Reactive Powder Concrete (RPC) is high-strength and durable composite produced with high

cement content. On the other hand, Geopolymers stand out as an alternative material to

Portland cement. In geopolymer production, industrial wastes such as silica fume,

granulated blast furnace slag and fly ash reduce environmental pollution. In this study, the

effect of curing temperature on the physical and mechanical properties of high-strength

reactive geopolymer concrete (RGC) was investigated. RGCs were cured for 8 hours at 40, 60

and 80 oC. Since the increase in curing temperature increased the evaporation of water in

the activator, the dry unit weight of RGCs decreased. As the curing temperature increased,

RGCs' compressive and flexural strength increased. RGCs cured at 80 oC for 8 hours had a

compressive strength of more than 140 MPa, while a flexural strength exceeded 10 MPa. The

increase in curing temperature decreases the capillary water absorption value of RGCs. A

denser matrix is obtained as the curing temperature increases, thus improving the physical

and mechanical properties. Due to the high matrix strength, cracks were observed on the

aggregate surfaces in SEM images. In addition, it was determined that silica fume

agglomerated in SEM images. It has been observed that gel voids smaller than 200 nm form

in the RGC matrix. As a result, it has been determined that high compressive strength can be

obtained in a short time (with low energy) at 80 oC temperature and 8 hours. Compressive

strength of more than 140 MPa was obtained after 8 hours without the need for high energy

like autoclave curing