Abstract
As the solution for the large emission volume of $CO_2$ during the process of cement manufacture and the cost efficiency of producing the ready mixed concrete, blast furnace slag has been widely used during the past years. However, as the differences of the manufacture process and raw materials of the blast furnace slag, it is difficult to secure stable quality of BS from various resources. In this study, nine types of blast furnace slag factories were chosen, and the physical properties of the blast furnace slags and the effect on the cement mortar with various replacing ratio were evaluated. The results showed high correlation between the qualities characters of blast furnace slag and mortar. Additionally the qualities of the blast furnace slag showed obviously difference from different factories. Some blast furnace slag were out of the standards of Korean Standard and American Concrete Institute. Based on these results, modification of the standard or enhance of the qualification were needed.