Effects of Curing Methods in Cold Regions on Strength of Concrete Incorporating Ground Granulated Blast Furnace Slag

This paper investigates the effects of various curing methods in cold weather conditions on the compressive strength of concrete incorporating ground granulated blast-furnace slag (GGBS). The specific surface area of GGBS (4000, 6000, and 8000 sq cm/g) was varied, as was the replacement level of cement by GGBS (50, 60, 70, and 80%). Mortar specimens were prepared for the experiment. The specimens were cured at 5 deg C constant and 20 deg C constant by atmospheric curing, water curing and sealed curing. Compressive strength test results were performed at various ages. Furthermore, the effects of applying heat curing at 30 deg C constant at early age to GGBS-concrete on the strength development were also examined. Results show the concrete incorporating the GGBS with the specific surface area of 8000 sq cm/g would have no strength development problem even though it were cured at 5 deg C by sealed curing. However, heat curing may have a bad influence on the strength development, particularly at later ages. On the other hand, GGBS-concrete with the specific surface area of 4000 sq cm/g would require heat curing in order to improve the compressive strength at early ages. Finally, based on the data derived from this experiment, the relationship between the compressive strength of concrete incorporating GGBS and maturity is discussed.