This study sought to examine the performance design of concrete mix proportions to ensure chloride resistance and early strength with respect to C35 (35 MPa), which is the minimum compressive strength class of concrete used in a marine environment. For the proposed concrete mixture, C24 (24 MPa) was selected and binders for concrete were manufactured using a blend of OPC (ordinary Portland cement), EPC (early Portland cement), and GGBS (ground granulated blast-furnace slag). The results of the experiment confirmed that the combined use of EPC and GGBS greatly improve the early-strength development and chloride resistance of concrete. An analysis revealed that the time for removal of forms can be reduced by 5-9 h from the aspect of early concrete strength. Moreover, in terms of construction productivity, EPC and GGBS were reduced by up to 16.39 h/cycle compared to other concretes. Regarding economic and environmental impacts, EPC and GGBS were more effective than C35 concrete. This study is significant as its findings help make it possible to examine the most economical concrete mix design in relation to strength development according to the application of EPC, GGBS, and PC-based admixtures.
Keywords: chloride resistance; early Portland cement; early strength; ground granulated blast-furnace slag; life cycle CO2; marine environment; time for removal of forms.