It is expected that construction waste include a waste concrete is continuously increase each year in the future. Theamount of construction waste is a lot and according to the nature of construction waste, it does not have a seriousenvironmental pollution and hazards. Therefore it is used as recycled aggregate directly or through a simple intermediatetreatment. The purpose of this study, recycled aggregate concrete used in a building structure system. Thus this studyfigure out which physical and mechanical characteristics of recycled aggregates concrete. According to replacement levelof recycled aggregates compared with natural aggregate, examine a life cycle CO2 emission and review cost efficiencyfor the practical use of recycled aggregate concrete. The result of this study that recycled aggregate concrete decline aCO2 emission and decrease material cost when a replacement level is increase. Carbon dioxide emissions per unit volumein aggregate by dry process according to substitution ratio compared with 0%, in 30% is 0.10%, in 50% is 0.34%, in100% is 0.58% reduce. Aggregate by wet process according to substitution ratio compared with 0%, in 30% is 0.02%,in 50% is 0.20%, in 100% is 0.35% reduce.

• 김태형(한양대학교 건축 및 도시환경공학과) | Tae-Hyoung Kim Corresponding author