Applicability of concrete containing the binary and ternary system of binder materials under natural marine environment

Fly ash (FA) and ground granulated blast slag (GGBS) have been employed to replace cement partially to reduce the environmental impact due to cement manufacturing. In addition, due to the depletion of sources, saline sand (sea sand) has been used as a fine aggregate for conventional concrete and fine-grained concrete. This study investigates the effects of fine aggregate replacement with FA and GGBS incorporated saline sand on the mechanical properties and durability of concrete. In this study, five types of concrete mixtures were prepared with different proportions of cement, FA, and GGBS for the specimens in the laboratory, while two of them were used at the site for a breakwater structure under natural marine environment. The compression test, splitting tensile test, and chloride penetration test were conducted on the specimen in the laboratory at the ages of 3,7, and 28 days, while the site samples for compression test and carbonation tests were conducted at 812 days. The laboratory results showed that the concrete mixture with the highest content (250 kg/m3) of GGBS has the best performance in compressive strength, splitting tensile strength, and resistance to chloride ion penetrability; whereas, the mixture with the lowest GGBS content (105 kg/m3) has the worst performance. Moreover, the site specimen results showed that the compressive strength of concrete incorporating GGBS and FA could be preserved in the marine environment.