Improving Quality of Fly ash Replace Concrete by Second-Class Blast Furnace Slag Powder and Gypsum

고로슬래그 미분말 2종 및 석고에 의한 플라이애시 치환 콘크리트의 품질 향상

This study is a basic experiment to complement the problems in decrease of strength in case we change lots of fly ash("FA" here in after) in ordinary portland cement("OPC" here in after). Mixing plaster that is known to be effective in improvement in hydration of blast furnace slag powder("BS" here in after). After FA changed concrete is mixed, the study physical proporties such as compression strength, increased proportionaly. When second-class BS 5 % and gypsum 2 % changed, compare to OPC strength approximately 120 % was recorded after one day. In FA 20 % case, according to the ratio of gypsum changed results showed similar trend, but compared to FA 10 % changed concrete, expression strength improvement was lower.