In order to analyze the effects of fly ash and blast furnace slag on CO2 uptake and compressive strengths in CO2 curing, twotests were carried out. First, the compressive strength test of a non CO2 cured specimen and a specimen with W/C 30% and20% admixture was conducted at three hours and three days while curing in a chamber with 20 oC and RH 60% after CO2curing for an hour. Second, the compressive strength test of a non CO2 cured specimen and a specimen with W/C 35-40% and10% admixture was conducted at 7 days and 28 days while curing in chamber with 60 oC and RH 100% after steam curingat 20 oC and RH 60% and CO2 curing for 2 hrs. In the first test results, the CO2 uptake rate of the case with 20% of admixturewas found to be 2% lower than the case without admixture, and CO2 curing turned out to be very effective in increasing theearly compressive strength. The second test results showed that CO2 uptake rate of the case with fly ash and blast furnace slagwas found to be similar with the case without admixture. Even in terms of increasing the compressive strength, CO2 curingof two hours was found to exhibit a similar strength development effect to steam curing of 4 hrs.

Keywords: CO2 curing, Carbonation, Fly ash, Blast furnace slag, Concrete product